In mid-1913, AT&T began working in earnest on the first telephone line to span a continent. Alexander Graham Bell himself inaugurated service on January 25, 1915, repeating from New York the famous words he’d spoken over his first telephone of 1876: “Mr. Watson, come here. I want you.” His former assistant, Thomas Watson, replied, “It would take me a week now,” as he was then enjoying his second career—as a Shakespearean actor—in San Francisco. The cost of a 3-minute call was then approximately $21 (roughly the equivalent of $500 today).
One century later four million cellphones are sold worldwide each day, allowing nearly 7 billion subscribers—equivalent to 98% of the earth’s population—to tap wirelessly at negligible cost into a vast global storehouse of information, misinformation and entertainment, and exchange 250,000 content-free text messages every second. Science and technology have given ordinary humans extraordinary powers beyond those of the richest potentates
of the previous century. Yet most of us are so jaded (or perhaps dazed) by the regu-larity of miracles that we rarely pause long enough to be amazed. For all that the average person knows, the technology that animates modern civilization came from a crashed alien spacecraft stored at Area 51, and relies on nanoscopic gnomes who seem mysteriously and benevolently inclined to grant our wishes more often than not.
Many pundits fear that an ignorant citizenry might be doomed to enslavement by the increasingly powerful forces that are shaping civilization. That may or may not be, but what is certain is that the intimate ways in which technology has insinuated itself into the fabric of existence argue for revisiting the question of what it means to be cultured and enlightened.
This book considers that question somewhat by proxy, by contemplating the revo-lutionary idea that has propelled civilization’s evolution at an ever-increasing pace for the last half-millennium in general, and the last century in particular. It’s that science, unlike other systems of thought, uniquely declares all of its truths to be provisional, constantly subject to re-evaluation and revision as evidence demands. In science an idea can be emotionally satisfying and breathtakingly elegant, but if it disagrees with experiment, it is wrong. It doesn’t matter if a Big Shot came up with the idea after many decades of arduous labor; it doesn’t matter if the expert is very attractive, kind to animals and has a mellifluous voice; it doesn’t matter how “intu-itively obvious” the idea feels, nor how well it comports with one’s personal philos-
ophy; it doesn’t even matter how many other experts also think that the idea is correct. If experiments say your hypothesis is wrong, your hypothesis is wrong. Sci-ence’s profoundly subversive notion that one may separate the validity of an idea from the authority who espouses it—that there exists a definite process for dispas-sionately separating fact from fertilizer—is what divides the modern from the ancient. It arguably defines “modern.” By reducing the amount of time and effort wasted on ideas that are false, the scientific method powerfully focuses our always-finite collective resources on activities that are more likely to yield fruit. The results speak for themselves.
To be clear, understand right now that this book isn’t directly about the scientific method. If it were, its title would be The Scientific Method, and it would be a snorefest that evil professors would wield to torment hapless undergrads; there would be deaths. Writing it would also be torment so, instead, this book is a collec-tion of stories. The focus is on the inventions and ideas that changed, and are changing, civilization. It’s on the people who came up with these ideas, on what inspired them to create, and on the socio-historical contexts that enabled their ideas to prevail at that time and place. The aim is to underscore that science is a human activity by talking about the active humans who came up with all this stuff. And since humans are involved, we’ll encounter blind alleys, naked greed, titanic egos, selfless geniuses, wingnut crackpots, heart-wrenching pathos and dumb luck.
The basic motivation for this book is hardly novel. Countless popularizations of science have preceded and informed it. Relatively few, however, have focused on the development of electricity (and electronics) that most of us use and depend on in our extraordinary lives. It is electricity that has most profoundly transformed human civilization over the last century by giving us easy access to the vast extra-corporeal accumulation of knowledge generated by our species over millennia. If you go back in time just 20 years, there is no Web. Another 10, and there are no cell phones, and only primitive personal computers. Go back another 30, and there are no silicon chips. Go back another 50 or so years, and there is no wireless communi-cation. Less than another 40 years back, and there is no electrical communication between America and Europe of any kind; messages are conveyed by ships and take two weeks, each way. It is astounding to contemplate how rapidly life for the ordinary person has changed in such a short time, all thanks to advances in electric-ity. Pause to consider that there are people alive today whose grandparents were born into a telephone-free world. Be amazed.
This book derives from a series of extemporaneous lectures improvised for an eponymous freshman seminar at Stanford University. Although conventional wis-dom holds that curiosity is largely beaten out of us by adulthood, it’s encouraging
that supporting evidence for that belief is weak. Certainly, the students in the semi-nar have been infinitely inquisitive. I am particularly grateful to the very first group of students, who bravely signed up for a class with a mysterious title and a purpose-fully vague syllabus. They quickly caught on to the fact that the class was all about curiosity, and how to satisfy it. What began as a trickle of queries ultimately became a flood. They asked so many questions, in fact, that we’ve had to leave out a great deal, perhaps to be answered someday in Stuff about Things.
She wasn’t wounded; she was dying. And he was as much a ghost. He finally accepted as inevitable what he’d first denied as even possible. In that newfound clarity he remembered his duty to all the others who were also in a twilight super-position of alive and not. That the RMS Titanic boasted a modern wireless telegraph gave Captain E. J. Smith his only small measure of hope. He would presently call upon the device for a miracle.
Bearing the burden for delivering that miracle were two twenty-something employ-ees of the Marconi Wireless Corporation: Senior Wireless Operator John George “Jack” Phillips and Junior Wireless Operator Harold Sydney Bride. With an equa-nimity that belied their youth, they dutifully tapped out Titanic’s urgent messages. With each press of the telegraph key, the five-kilowatt Marconi spark transmitter buzzed and crackled potently as it impelled evanescent dots and dashes into the moonless sky. Throughout the night, invisible electromagnetic kinks cascaded out-ward from the ship’s antennas at light speed, bearing at first the distress call CQD,
and then the much newer SOS.1 After each transmission, Phillips and Bride listened hopefully for a response. They made out replies intermittently, but from stations too distant to matter. At other times, their receiver registered only the indifferent static of a restless aether. Knowing that they’d have to do better for the 2200 passengers and crew, they checked and re-checked their apparatus, making continual adjust-ments along the way. They worried about the transmitter, for it had failed just a day earlier. They’d rebuilt it themselves, in violation of Marconi regulations forbidding
onboard repair. They quickly verified with some pride that their repair job was holding up well. They tuned everything, turned knobs, flipped switches—they did all the geeky things that geeks can do. They’d hoped to raise the Californian, recently so close that her lights had been visible on the horizon. Alas, her sole wire-less operator had gone to bed shortly before the collision. Finally, a strong signal came booming in from the Carpathia. Her wireless operator, Harold Cottam, had been away from his receiver when Titanic first sent out her distress call. He made the fateful decision to listen to some sports news before turning in for the night. Upon firing up his receiver, he heard about the Titanic from the Cape Race wireless station in Newfoundland. He rushed to awaken Captain Arthur Rostron, who then immediately issued orders to push the Carpathia’s steam engines beyond safe lim-its, as she was then almost 100 kilometers—and thus several hours—away. Cottam hustled back to his station to assure Titanic that the Carpathia was on her way faster than prudence would allow.
Phillips and Bride relayed the message to Captain Smith. The duo remained at their station to make sure that the Carpathia would find its way to the Titanic. Keeping the wireless set tuned up as the generators started to misbehave presented a chal-lenge made more difficult by the need to ignore the growing roar of water as it gushed into the stricken ship. They thought only of guiding the Carpathia to them as fast as possible, transmitting news of Titanic’s rapidly worsening situation along with updated position estimates. After two frenetic hours that had passed both too quickly and too slowly, Captain Smith called on them personally. Conveying pride and gratitude in understatement, he told them, “You can go now, boys. You've done your job well,” as he formally released them under the “every man for himself” rule. Knowing that minutes could matter, Phillips and Bride nevertheless continued sending, finally stopping only when imminent failure of the generators took the decision out of their hands. With the ship soon to go dark forever and the frigid Atlantic lapping ominously at the floorboards, they managed to tap out one final message to Cottam: “We are sinking fast, passengers being put into boats.” Then, out of professional habit, Phillips reflexively flipped a knife switch downward to disconnect the transmitter from the generator. As he and Bride prepared to depart, a stoker intent on stealing Phillips’ lifebelt rushed into the wireless room. After pre-vailing in a frantic, deadly battle, the shaken pair finally made their way topside,
1. A common misconception is that these abbreviations stand for “come quickly; distress” and “save our ship” (or some variants thereof). The prefix “CQ” (a homonym of “seek you”) had long been the equivalent of ahem in wireline telegraphy, so that CQD simply means “attention: distress.” “SOS” was chosen for its recognizability and mnemonic value (three dots, three dashes, three dots). Its use had been ratified by international treaty in 1908, but had not yet displaced CQD by the time of the Titanic.
only to discover that their difficulties were not quite over: Only one small lifeboat remained. They stood on the rapidly shrinking patch of deck and quietly considered their meager options. The air felt still and cold.
The water would feel colder.
The remaining lifeboat washed off the deck before it could be launched. Phillips and Bride dove into the freezing water, ending up underneath the capsized craft. They struggled to get out from under the boat and, along with fifteen other survi-vors, clung to it as the waterlogged lifeboat slowly sank. Phillips succumbed to hypothermia shortly before the Carpathia arrived, joining the 1500 souls claimed by the ocean that April night in 1912. Bride miraculously survived, along with 704 others that he and Phillips had saved. Despite serious injuries that included a very frostbitten foot, he even assisted Cottam in another marathon session in advance of their arrival in New York, sending out news and an endless stream of personal mes-sages from the survivors.
FIGURE 1. Wireless heroes Jack Phillips (left) and Harold Bride
Among the legacies of the Titanic disaster was a requirement for wireless apparatus on passenger ships and, unlike the Californian, an operator on duty at all times. And, although the rescue had not been the first enabled by wireless, the drama underscored in the public’s mind how far the electrical arts had progressed in a short time. In rapid succession, the telegraph, incandescent light, telephone, and now wireless had shown powerfully that the study of electricity was no longer the elite and largely useless diversion that it had been for centuries. How these inven-tions “annihilated space and time” in the truncated span of a few decades is a remarkable tale that begs recounting.
Nearly a century after the Titanic went to its final rest, film director James Cameron documented his return to the wreckage in Last Mysteries of the Titanic. Maneuver-ing a robot camera into the wireless room, Cameron pointed out the transmitter controls. As silent and poignant testaments to professionalism in those last, desper-ate minutes the generator was cranked up and the power switch was in the down position, just as Bride had testified. Cameron was moved to say, “These guys were heroes. They were the computer geniuses—the computer geeks—of their day.”
The spark apparatus used by Phillips and Bride owed its existence to the collective effort of geeks spanning many continents and centuries. The first geek in recorded history, according to tradition, was Thales of Miletus (Θαλησ ο Μιλησιοσ). He was born in that Aegean port city in what is now Turkey, and spent his days think-ing great thoughts around 600 BCE, when Nebuchadnezzar still ruled Babylon. Thales was one of the Seven Sages of Greece, and the first Greek mentioned in con-nection with philosophy, mathematics and science (indeed, he is one of the earliest Greeks mentioned in history). No writings by Thales or his contemporaries have survived, but entertaining (and probably apocryphal) stories about Thales abound. They generally describe archetypal geek behavior, such as tripping and falling while lost in thought (“[If you can’t even see] what is under your feet, [how can
you] understand what is in the sky?”). Such stories are unreliable in detail, but their very existence perhaps does establish Thales as the first nerd. He’d have worn a pocket protector, if Greek garb had had pockets.
Charming tales aside, tradition frequently awards him priority in the discovery of either magnetic or electrostatic attraction (“static cling”), or both. A common story, for example, is that Thales was the first to note that small bits of lint, straw or the barbs of a feather are attracted to a piece of amber (ηλεκτρον, most commonly transliterated as elektron) that has been rubbed with cloth (or animal fur, in other recountings), as depicted in the postage stamp of Figure 2.
FIGURE 2. Greek stamp honoring Thales (note the amber and feather)
Countless textbooks, encyclopedias (including the usually rock-solid Britannica) and web pages present as factual this standard story of Thales, amber and feathers. It’s a nice tale, and although Thales seems as deserving of the honor as any, it is just
that — a tale.2 Certainly, the phenomenon of static cling would have been noticed by many of the ancients, but writers seem to feel happier if they can assign credit for a discovery to a specific person, rather than to an anonymous, amorphous group.
2. Because a resolution of this question is unimportant to our narrative, we defer further dis-cussion of the issue to the Appendix at the end of this chapter.
Whether Thales actually made the first—or any—observations of the amber effect is largely irrelevant, as the limited consumer market for feeble feather attractors assured the subject’s neglect for a millennium or two. Magnetism fared much bet-ter, with the Han Dynasty Chinese first exploiting the phenomenon to make com-passes starting around 200 BCE for geomancy (feng shui and all that), to identify favorable burial sites and such. These early compasses were unwieldy affairs with spoon-shaped lodestones whose handles were supposed to point south (see Figure 3).
FIGURE 3. Modern replica of Han Dynasty compass
Even with well-made spoons and highly polished bases, the friction at the point(s) of contact between the spoon and plate was large enough to inhibit motion. The accuracy and repeatability of such compasses was correspondingly too poor for most navigational purposes.
It’s not known precisely when the magnet’s potential for navigation became widely appreciated, but the first written description of how to produce a compass that would be suitable for this purpose is found in Meng Xi Bi Tan (Dream Pool Essays) by Song Dynasty scholar Shen Kuo (Shen Gua) in 1086 CE. The essay describes
how an iron needle drawn across a piece of lodestone itself becomes magnetized, and how a needle so prepared may be used as a compass by suspending it with a fine thread affixed to the center with a bit of wax. He reports that, as with the spoon, one may not know in advance which end of the needle will point south. A generation later, his countryman Zhu Yu would be able to write, in Pingzhou Ke
Tan (Pingzhou Table Talks) of 1117 CE,
The navigator knows the geography, he watches the stars at night, watches the sun
at day; when it is dark and cloudy, he watches the compass.3
Judging from the chronological sequence of writings on the subject, knowledge of the compass seems to have spread along the Silk Road to the Arab world, and from there to the West. The first written description of the compass in Europe is found in Alexander Neckham’s De Naturis Rerum (“On the Natures of Things,” believed to have been written by the English monk around 1190), and which adds a bit to Zhu Yu:
Sailors, moreover...when in cloudy weather...touch the lodestone with a needle, which (the needle) is whirled round in a circle until when its motion ceases, its
point looks direct to the north.4
By the early 13th century, the compass had finally developed into an essential tool of navigation the world over, even if no one was quite sure how it worked. The pre-vailing opinion was that a magnet magically points toward Polaris, the Pole Star, not to a location on Earth.
Given the newly acknowledged importance of the compass, it’s no surprise that the first treatise on magnetism appears around this time. Its author, Pierre de Maricourt (better known as Petrus Peregrinus — Peter the Pilgrim, implying that he’d been a Crusader), was an engineer in the army of Charles d’Anjou (Charles I of Sicily) during an extended siege of Lucera (sometimes rendered Luceria or Nocera) in southeastern Italy. Medieval sieges tended to be somewhat slowly paced affairs and thus demanded patience; the primitive technology of the day didn’t support the fre-netic cadence of modern mechanized warfare (think about the scene in Monty
Python and the Holy Grail where a soldier cries out “Fetchez la vache!” before a cow is catapulted over a castle wall, and you get the idea). Thus did Peregrinus
3. http://en.wikipedia.org/wiki/Compass.4. The Letter of Petrus Peregrinus on the Magnet, translated by Brother Arnold, McGraw,
apparently find enough free time to document contemporary compass design, carry out experiments on magnetism, and propose a perpetual motion machine based on
an ingenious arrangement of magnets.5 Dated 8 August 1269, the 3500-word Epis-
tola de magnete describes those activities.6 Here, for the first time, we read that magnets have two “poles” (the first appearance of that term in connection with magnetism), that like poles repel, and that unlike poles attract. Furthermore, Pere-grinus observes that breaking a magnet into two pieces always produces two whole magnets, each with two poles of opposite type; a “single-pole” magnet (a mono-
pole) is never observed. He also considers two possible explanations for how a compass works its magic. Peregrinus dismisses as ridiculous a popular theory that a magnet works because of a massive range of lodestone mountains at the north pole. Instead he concludes that a compass needle points to the Pole Star because of some power (“virtue”) it receives from the heavens. Even though he is wrong on that point, Peregrinus deserves credit for the first quasi-scientific study of magnetism. The Epistola — perhaps the first scientific paper, period — was sufficiently com-plete that centuries elapsed before anyone added anything useful to it. Before Gutenberg and his printing press, Peregrinus’ letter could be found in only a few
libraries. It was eventually published widely, but in plagiarized form.7 No one went beyond Peregrinus until the year 1600.
As round-numbered years go, 1600 is less arbitrary than many others as a boundary separating one era from another (in this case, the Baroque from the Renaissance). A young Pieter Pauwel (Peter Paul) Rubens journeyed from Antwerp to Venice that year, soon to astonish the art world with his sumptuous, sensuous style. Many would later call him the most important artist of the century. At the same time,
Jacopo Peri (“Zazzerino”)8 of Florence was exploring new musical forms, of which
5. The cheerful enthusiasm he expresses for his perpetual motion machine tells us that he didn’t try to build it.
6. The full citation is Epistola Petri Peregrini de Maricourt ad Sygerum de Foucaucourt, militem, de magnete (“Letter from Petrus Peregrinus of Maricourt to Syger of Foucau-court, soldier, on the magnet”). Peregrinus clearly had lots of time on his hands.
7. If imitation is the sincerest form of flattery, then de Maricourt’s head would have exploded sincerely. In 1572 the Belgian Johannes Taysner (Jean Taisner or Taisnier) tried to pass off as original his plagiarized version of the Epistola, believing that the 300-year gap would be enough for no one to notice (“the key to looking intelligent is to hide your sources”). It was, but only for a short while. His attempt at deception was further hin-dered by his inclusion of a treatise on falling bodies written by a fellow named Benedetti, again without attribution.
8. Other popular nicknames include the Zazzman, Zazzmeister, and my personal favorite, the Zazzinator.
the opera looked particularly exciting. He cowrote Euridice that year (the oldest opera extant; his earlier Dafne is lost). That flowering of creativity was perversely mirrored in the Vatican’s practice of immolation to execute heretics (specifically, heretics who recanted falsely). Because of a proscription against drawing blood, burning at the stake was deemed a more righteous method of dispatching defective souls to the hereafter. And so it came to pass that this diabolically ingenious solu-tion was applied in 1600 to the vexing problem of Giordano Bruno, who had been sentenced for various heresies that included his stubborn belief in a Copernican solar system. Decades later, how Bruno met his end would still be a fresh memory for one Galileo Galilei.
A thousand miles away, 36-year old William Shakespeare’s powers were at their peak, with audiences about to enjoy his latest play, Hamlet, at the newly-built Globe Theater. At the same time, a fellow London denizen, William Gilbert, was enjoying conspicuous successes of his own. His widespread fame as a medical doc-tor had recently led to his being named court physician to Elizabeth I. Fortunately, the 67-year old queen enjoyed generally good health, leaving Gilbert with ample time to continue indulging his intense passion for research on electricity and mag-netism. Friends were frequently in attendance as collaborators and spectators while he carried out experiments at his elaborate home laboratory, using many instru-ments of his own devising. He was deeply irritated to discover through these exper-iments that much of what had been written and repeated as fact over the centuries was wrong:
The writers deal only in words that involve subject matter in thicker darkness; they treat the subject esoterically, miracle-mongeringly, abstrusely, reconditely, mysti-cally. Hence such philosophy bears no fruit, for it rests simply on a few strange Greek terms just as our barbers [who then offered medical services as well as hair-cuts] toss off a few Latin words in the hearing of the ignorant rabble in token of their learning and thus win reputation; bears no fruit because few of the philoso-phers themselves are investigators or have any firsthand acquaintance with things; most of them are indolent and untrained, add nothing to knowledge by their writ-ings, and are blind to the things that might throw a light upon their reasonings. [De Magnete, Book 2, Chapter 2; Translation by P. Fleury Mottelay]
Not as much has changed in 400 years as one would’ve hoped. The simple, reason-able and profound notion that ideas and assertions should be put to the test is still not nearly as widely held as it should be.
On top of additional rants against self-proclaimed authorities who were often wrong but never in doubt, Gilbert reported on a vast array of original experiments
in a classic tome called De Magnete.9 From the title, you can see that Latin was still the language of scholarly communication, although Shakespeare’s success at show-casing the rich literary potential of English would eventually relegate Latin to the status of a quaint linguistic relic.
FIGURE 4. Portrait of William Gilbert
In perhaps his most famous experiment, Gilbert fashioned a sphere out of lode-
stone, calling it a terrella (“little Earth”).10 After careful measurements with a
9. De Magnete, Magneticisque Corporibus, et Magno Magnete Tellure; Physiologia Nova, Plurimis et Argumentis, et Experimentis Demonstrata (“On magnets, and magnetic bod-ies, and the great magnet, the Earth; a new natural philosophy, demonstrated with many arguments and experiments”).
10.Peregrinus had also described a lodestone sphere, but only in the context of how to locate its two magnetic poles by experiment. Gilbert’s insight was to regard the sphere as an analog of the Earth, allowing him to carry this idea to the logical conclusion that Peregri-nus had missed.
small compass moved over its surface, he showed that he could reproduce in minia-ture the known behavior of compasses on the Earth. The stunning implication is that the Earth itself acts as a giant magnet, making it is unnecessary to invoke the existence of a huge lodestone mountain and also unnecessary to assume a mystical exchange of “influences” with Polaris to explain the operation of compasses. Of course, there still remained unanswered the question of precisely how magnets work, but at least he reduced the number of unknowns by telling future scientists
(natural philosophers, to use the term then in vogue) where not to look.11
In his thorough checking of the received wisdom he disproved, among other things, a prevailing belief that garlic diminishes a magnet’s strength (an idea traceable to at least as far back as Pliny the Elder). Despite his clear experimental demonstrations, it nevertheless remained a floggable offense in the British Navy for more than
another century for a helmsman to approach a ship’s compass after eating garlic.12
We also have Gilbert to thank for explicitly treating magnetism and the amber effect as two different phenomena. Before him, there was a tendency to lump them
together (“things that attract other things”).13 We also have him to thank for devis-ing a compact alternative to the term “amber effect.” In Figure 5 we see an excerpt from De Magnete (Book 2, to be precise) in which the term electrica first appears in print anywhere (the relevant phrase is circled), among Gilbert’s enumeration of materials that exhibit the amber effect.
11.The subject of philosophy was then much broader than it is today, encompassing the physical sciences as well as the contemplation of one’s navel. Linguistic relics reflect this older usage, for example in the Ph.D. degree conferred to scientists and metaphysicians alike.
12.A primary source for this assertion remains to be found; it may turn out to be apocryphal.13.Girolamo Cardano, an Italian and Renaissance man (in all senses of that term) much more
famous for having been the first to publish algebraic solutions for the roots of cubic and quartic equations, also clearly understood the difference between magnetism and the amber effect. He published his thoughts in De Subtilitate (“On Precision”) in 1560, but Gilbert’s influence was much greater, perhaps because Cardano discussed so many differ-ent topics in De Subtilitate.
FIGURE 5. First appearance of electrica (De Magnete, Book 2, Chapter 2)
The excerpt translates very roughly as14
... of soda, and belemnites [which we now know are fossils of prehistoric squid-like creatures]. Also attracting are sulphur, mastic, and hard sealing wax of lac tinted various colors. Hard resin attracts, as does arsenicum [arsenic oxide], but weakly; feebly also and favoring dry air are rock salt, mirror stone [mica], and rock alum. Such [an effect] is possible to see, when the air mid-winter is frigid, and clear, and thin; when the electrical effluvia of the earth are less impeded, and the electric bod-ies are harder; of such things, later. All these are attracted...
His use of effluvia reflects Gilbert’s belief that magnetic and electric effects are due to the emission of some gas- or fluid-like substance. Just as cedar can emit a scent for quite a long time without any noticeable change in the host material, he postu-lates that magnetic and electric materials are analogous emitters of insubstantial but potent “vapors” of a kind. His imagery of something flowing out of these materials would provide subsequent generations valuable fluid analogies for explaining elec-trical phenomena. Although flawed (as all analogies ultimately must be), the intui-tions derived from this imagery would prove fruitful nonetheless, and would profoundly influence the lexicon of the subject.
Another English physician, Thomas Browne, would take the next, nearly inevitable etymological step, fashioning from Gilbert’s Latin electrica the English words elec-
trical (electricall) in 1635, as well as electric (electrick) and electricity in 1646.15
14.As is evident from its awkwardness, we’ve chosen to provide a more literal, rather than literary, translation than is customarily available.
Gilbert’s London was crowded and noisy, as well as noisome with effluvia of an unwholesome organic sort. As was then common in Europe, the 200,000 or so inhabitants in and around the city regularly emptied their chamber pots onto the streets. Although a prototype flush toilet had been demonstrated to Queen Elizabeth
in 1596, it would not be widely used for centuries.16 Pedestrians were always at risk of encountering a shower of refuse from thoughtless residents above street level (no wonder Londoners wore tall hats — see Figure 4). Only London’s rains cleaned the streets from time to time. The city’s Fleet River (better known as Fleet Ditch, and for which Fleet Street is named) was essentially an open sewer that teemed with rats and their fleas. Not surprisingly, the plague tended to recur during the warm summer months with alarming regularity. Many well-to-do Londoners prudently spent those months in the country to avoid catastrophes such as the out-break of 1592 which killed 15,000 (almost 10% of the population). Gilbert was unfortunately in the city when another serious outbreak occurred in 1603. He and his primitive medical skills were no match for the fleas that carried the plague. Gil-bert breathed his last in November of that year, six months shy of his 60th birthday, and eight months after the Queen herself had passed away (evidently from old age).
Gilbert the man may have left us, but De Magnete endures. This immortal work has enlightened and even enraged while inspiring others to take up research on electric-ity and magnetism. Nicolò Cabeo, an Italian Jesuit priest, chose to study the sub-jects because he found so many of the book’s statements provocative. Forced eventually to concede that Gilbert had correctly described his experimental results, all Cabeo could do was disagree with Gilbert’s interpretations (he found the “efflu-via theory” less than convincing). He did more than merely replicate Gilbert’s work, however, and demonstrated electricity’s ability to repel as well as to attract, reporting on these findings in 1620 in Philosophia Magnetica. Finally, 350 years after Peregrinus, electricity and magnetism were each understood to attract and repel. That qualitative similarity hinted that electricity and magnetism might be related somehow, but it would take another two centuries before someone would lift the veil of that mystery.
One impediment to research had always been the temporary nature of the electrical effects produced by rubbing things against stuff, to say nothing of the inconve-
16.And no, it was not invented by a guy named Thomas Crapper. There was indeed a plumber by that name, but he lived in the late 1800’s, long after the flush toilet had been invented.
nience of having to rub in the first place. Otto von Guericke, the popular bürger-meister of Magdeburg, took an important first step toward solving these
problems.17 Despite the chaos and deprivation directly following the Thirty Years’ War, von Guericke found the time to carry out important research. Perhaps the Mayor made time for these diversions precisely to take his mind off of the pathos surrounding him as the Holy Roman Empire crumbled. Whatever the reason, von Guericke accomplished more in his spare time than most achieve at their full-time professions.
Taking his inspiration from Gilbert, he sought to make a terrella, but an electric one. The absence of an electrical compass phenomenon makes von Guericke’s choice a bit curious, but he was guided by mystical notions of the universe. He chose sulfur, partly because it was one of the materials discovered by Gilbert to be electric (as seen in Figure 5), but mainly because of its importance in alchemy (another subject with which he was preoccupied). He fashioned his terrella by pour-ing molten sulfur into a glass globe, and then breaking the glass after the sulfur had cooled to a solid. As seen in Figure 6 a stick served as a handle for rotating the ball. When mounted in the wooden frame shown, spinning the rod with one hand and rubbing a cloth against the ball with the other produced good results. He reported in his Experimenta Nova of 1672 that a sulfur ball charged in this manner produces much more powerful effects than had been obtained with amber. Under some con-ditions, it would even generate visible and audible sparks. These were feeble effects, certainly, but they were sensible nonetheless. Von Guericke thus was the first to produce miniature lightning on demand, but neither he nor anyone else knew exactly how.
17.He was born Otto Gericke. Upon his elevation to the peerage, he became Otto von Guer-icke. The consequent change in the spelling of the last name has tripped up more than one biographer.
FIGURE 6. Von Guericke (l) and his generator, Die Elektrisiermaschine
Von Guericke is much better known for experiments with an early vacuum pump that he made by operating a water pump backwards. He coupled two large hemi-spheres together with a leather gasket, then pumped out the air as well as he could, testing the Aristotelian assertion that Nature abhors a vacuum. Today, the phrase is used metaphorically, but in von Guericke’s time, it referred to a widely accepted declaration by Aristotle that a vacuum simply could not exist. Von Guericke was amazed to find that he could not pull apart these 55cm-diameter “Magdeburg
Hemispheres,” no matter how hard he tried.18 He was more amazed to find out that sixteen horses (a team of eight pulling on each hemisphere) couldn’t, either. Evi-dently, Nature’s abhorrence doesn’t prevent the production of a vacuum after all. The drama of that demonstration so overshadowed his achievements with the sul-fur-ball static generator that few other scientists were inspired to work with Die
Elektrisiermaschine.
Or maybe it was the smell.
One scientist that von Guericke’s electrical work did manage to inspire was Francis
Hauksbee (Hawksbee).19 Like the great Gilbert a century earlier, Hauksbee was born in Colchester and lived his professional life in London. Hauksbee was a bril-
18.These spheres are currently on display in the fabulous Deutsches Museum in Munich.
liant, self-taught scientist, a skilled maker of instruments, and a virtuoso experi-mentalist. His self-published book of 1709, Physico-Mechanical Experiments on
Various Subjects, Containing an Account of Several Surprising Phenomena Touch-
ing Light and Electricity, chronicles a lifetime of experimentation. Hauksbee explains in his book that von Guericke’s electrical generator continues to work just fine when a glass globe is substituted for the sulfur ball.
FIGURE 7. Diagram from his book of Hauksbee’s glass globe machine
He also describes the wondrous effects obtained when another glass sphere contain-ing a small quantity of mercury and very little air (using a vacuum pump much like von Guericke’s) is brought in proximity with the machine. The beautiful glow that results is bright enough to read by. Moreover, the patterns of light vary as a hand moves over the surface of the globe. Hauksbee was thus the first to build a “plasma globe” (descendants of which continue to sell well in novelty shops). Not only that,
19.As with Pliny, there is sometimes confusion about whether we are talking about the Elder or the Younger. Here, we refer only to Hauksbee the Elder.
but his glowing sphere is also an ancestor of the modern fluorescent light, which depends on the same phenomenon of glowing mercury vapor for its operation. Unlike von Guericke’s sulfur device, Hauksbee’s machine soon became a standard piece of laboratory equipment all over the world. Note to future scientists: If your machine doesn’t stink up the joint, more people will use it.
Hauksbee’s book and apparatus did much to stimulate the development of electrical understanding by accelerating the pace of discovery. That acceleration was com-pounded by the research of an unlikely scientist named Stephen Gray. Although he lacked a formal education and eked out a meager living as a dyer in Canterbury, he dreamed of bigger things. He was a nerd at heart, and “nerdiness will out.” He was fortunate that his social circle included a number of wealthy individuals who accepted the friendship of someone of low station. They shared their libraries and instruments, and he soon taught himself enough to become a conspicuously tal-ented amateur astronomer. He made a number of minor, though notable, discoveries with a telescope he’d built himself. The quality of his work brought him to the attention of John Flamsteed, Britain’s first Astronomer Royal. Flamsteed was over-seeing the construction of the new observatory at Greenwich, and hired Gray to assist him. When another observatory was under construction in Cambridge, Gray assisted again. Unfortunately, Sir Isaac Newton and Flamsteed were adversaries and Gray suffered when Newton inevitably triumphed. Gray’s finances had never been robust, so he could scarcely afford the loss of his position, no matter how low the pay might have been. Flamsteed fortunately retained enough influence to arrange for Gray to receive a pensioned position at a government-supported home for destitute men (the Charterhouse). With room and board thus secure, Gray (still a nerd in late middle age) embarked on a second scientific career, choosing electricity as his new obsession.
Previous researchers had been preoccupied with the creation of an electrical effect (primarily by friction). By 1729, the 63-year old Gray had classified materials into two new categories, distinguished by whether they could convey an electric effect. In the course of his investigations, in fact, he transmitted an electrical effect (the classical amber effect of picking up small bits of fluff) over a distance of 250 meters. He thus may be considered the inventor of a crude electrical telegraph. Gray noted that some materials, particularly metals, convey electrical signals well, while other materials, such as dry silk, do not. His friend and colleague John Desaguliers gave the names conductors and insulators to these two classes of mate-rials, and these terms have been used ever since.
Gray’s work intrigued the French chemist Charles François de Cisternay du Fay (undoubtedly Chuck to his friends), who visited him and listened attentively as
Gray described the results of his many experiments. After returning to Paris, du Fay carried out his own investigations. He felt that the results could be understood within a framework of two types of electricity, one which he called vitreous, and the other, resinous, so named because they were produced by friction with glass-like or amber-like materials, respectively. Unlike conductor and insulator, these terms have not survived to the modern day, having been replaced by positive and negative. In 1734 du Fay published his restatement of Gilbert’s theory of effluvia, replacing the mysterious gas-like emanations imagined by Gilbert with two differ-ent (but still mysterious) gas-like emanations. According to this new idea an unelectrified body fails to attract or repel because it contains equal quantities of res-inous and vitreous electricity. If these types of electricity are not in balance, then the familiar effects of attraction and repulsion emerge. This theory appeared to explain a great many things and therefore begged further investigation. Sadly, nei-ther Gray nor du Fay was able to pursue this topic to conclusion. Gray passed away in 1736 and was buried in a common grave for Charterhouse pensioners. It is sad that his name is but a footnote in the history books (if he is mentioned at all). Du Fay died three years later at 40 after struggling briefly with an unspecified illness.
It hurts when I do that
Du Fay’s work attached great importance to the view of electricity as a sort of fluid. But how “real” was this view? Was electricity truly a fluid? That question was aris-ing with increasing frequency, and several scientists resolved to answer it. In Janu-ary of 1746 at the University of Leyden in the Netherlands, Professor Pieter van Musschenbroek and his student, Andreas Cunaeus, were seeking ways to store elec-tricity. Guided by the image of electricity as a sort of fluid, van Musschenbroek and Cunaeus attempted literally to pour electricity into a jar. They connected the busi-ness end of a friction generator to the inside of an otherwise empty jar. That didn’t work; when the generator stopped, they couldn’t get any juice out of the jar. Then they filled the jar with water, thinking that perhaps the electric fluid (whatever that might be) would dissolve in it. They were disappointed to obtain the same null result as without water. After a lengthy, frustrating series of failures, it was time to disassemble the apparatus and perhaps move on to better things. Cunaeus picked up the jar with one hand, and went to pull the wire out of the water with his other. Every nerve in his body lit up. He was certain that he was going to die. A fine Dutch expletive and a loud crash likely announced the discovery of the “Leyden jar.”
At least the experiment was a success. Cunaeus quickly recovered and lived to enjoy fame as co-discoverer of the Leyden jar.
Van Musschenbroek experienced his own accidental electric shock a short time later. He reported to the French scientist René-Antoine Ferchault de Réaumur (inventor of the alcohol thermometer) that it took two days to feel like himself again and that he would not take a second shock for the entire kingdom of France.
Further experimentation by less-traumatized researchers revealed that water was unnecessary. William Watson (an English physician, in the tradition of Gilbert) showed around 1747 that lining a glass jar with metal foil on the inner and outer surfaces produced much the same behavior without water. That arrangement worked somewhat better, in fact, and this form of the Leyden jar quickly came to dominate.
FIGURE 8. Leyden jar of Watson’s type (shown here being discharged)
Watson was even able to send an electrical effect across the Thames at Westminster Bridge that year. A modified Leyden jar of his design connected to one end of a wire was able to produce a visible spark at the other end. We see in Watson’s exper-iment yet another anticipation of electrical telegraphy.
From the success of Watson’s water-free jar, scientists came to understand that van Musschenbroek and Cunaeus had gotten the result that they were seeking entirely by accident. Accident or not, the Leyden jar proved an important development. By acting as an accumulator of electricity, scientists could “charge up” the Leyden jar
with a friction generator, and then discharge the jar all at once, allowing them to produce more powerful effects (like near-electrocution) than had been possible. The device is today called a capacitor, and appears in less dramatic forms in virtu-ally every electronic circuit.
As it happens, the Leyden jar was actually discovered a couple of months earlier, by the Pomeranian cleric Ewald Jürgens Georg von Kleist. In October of 1745 he, too, had stumbled across the “Leyden” jar after traversing a path remarkably simi-lar to that followed later by van Musschenbroek and Cunaeus. He’d reported his findings in November, thus anticipating the Leyden group by a couple of months. Nevertheless, the name Leyden jar was coined early on and stuck, and relatively few today are even aware that von Kleist was first. Perhaps it’s just as well, for “Pomeranian jar” sounds rather like a storage container for a small dog.
So, how does a Leyden jar work? For that matter, how do those friction machines work? Let’s answer those questions now, rather than waiting for another 150 years of history to pass, and get started on disentangling a language problem associated with electricity.
Today, we have the benefit of knowing that matter consists of atoms, and that atoms
contain electrons. These are modern notions, of course.20 The investigators we’ve introduced so far did not know about the structure of matter, and so they groped in the darkness. In fact, it is their struggle that has illuminated and informed our understanding. They could not know that friction machines depend on the fact that electrons in a given material are bound imperfectly to their host atoms. The strength of this binding depends on the details of the material, as well as on external factors such as temperature. It is more likely than not that two different materials will have differing affinities for electrons. Consequently, a net transfer of electrons will gen-erally take place to the material with the greater affinity, leaving that material with a net surplus of electrons, and the other with a deficiency of electrons. To use du Fay’s language, one material will exhibit vitreous electricity, and the other will be resinous. In modern terms, one will be positively charged, and the other will be negatively charged.
From the foregoing description, it would seem that rubbing is not fundamentally needed. Indeed, that’s right. Contact between dissimilar materials is the basic requirement. Anyone who has seen the sparks produced as a piece of cellophane adhesive tape is rapidly pulled off a surface has seen evidence that this is the case.
Rubbing is simply an expedient way to get a greater surface area to come into inti-mate contact (the key word is intimate, for a separation of a few atomic diameters is sufficient to prevent functioning).
Again, depending on the materials involved, as well as on external factors (such as temperature and humidity), the state of charge of a material may persist for varying amounts of time. With good insulators, it’s possible for charge to be retained for hours or days (yet longer durations are possible, but less common).
It’s also possible for two identical materials to have different states of charge, but not without an external influence to break the symmetry. A friction generator is a perfect external influence for driving the transfer of some charge from one metal electrode to another in a Leyden jar. Thanks to the excellent insulating qualities of the jar’s glass, any displacement of charge can persist for a surprisingly long time. Researchers quickly discovered that one could get a nasty shock from a Leyden jar that has lain undisturbed for hours or even days.
Over the years, the phrase “charge up a Leyden jar” or “charge up a capacitor” came into common usage. To many, that evokes an image of filling up a jar with electrons, but that isn’t the right picture at all. What actually happens is that some charge from one electrode moves over to the other; the total amount of charge doesn’t change. And if the phrase is “charge it up with electricity” we have a double language problem. Here, electricity is not a substitute for electrons. Rather, it is being used as a proxy for “electrical energy.” Charges that have been separated have the potential to perform some function as they attempt to return to their unsep-arated state. They can move things, heat things, break things. Thus, “charge it up with electricity” really means “separate charges so that they will have electrical potential energy.” The cumbersome nature of the more accurate statement explains why the shorthand language is universally used, misleading as it may be.
With that interlude completed, we can now relate the wonderful story of Abbé Jean-Antoine Nollet. It is he who named and popularized the Leyden jar, but he’s better remembered for a delightful experiment to determine “the speed of electricity.” Again, this phrase must not be taken to mean “the speed of electrons.” Rather, inter-pret it as meaning “the speed with which an electrical effect may travel.” In 1746 he arranged enough Carthusian monks to form a circle of about a mile in circumfer-
ence (that’s a lot of monks).21 Each monk was electrically connected to his neigh-bors through a length of iron wire. When Nollet connected a charged Leyden jar to the assembly, the monks all leapt into the air at the same time. Luckily, monks of the Carthusian order don’t take a vow of silence, for there was almost certainly
some shouting. Nollet’s charming demonstration showed that electrical effects are powerful, travel a significant distance and move very fast.
FIGURE 9. The Abbé Jean-Antoine Nollet
Up to this point, the story of electricity is purely European, driven mainly by gen-tlemen born of high station. The next big contribution comes from the New World, from someone who began life near the bottom of society. Benjamin Franklin was the tenth of seventeen children of a Boston soap maker. His poor family appren-ticed him at the age of 12 to his older brother, James, a printer. He and James did not get along, unfortunately, and Ben eventually ran away to Philadelphia. Arriving with only enough money for a few breadrolls to munch on, the 17-year old Franklin managed to find employment in printing shops. The runaway teen eventually became a wealthy and respected social lion, and chose to retire at the age of 42.
He was free to pursue whatever activities interested him, and at that time in his life, electricity was his preoccupation. A gentleman (and Fellow of the Royal Society) named Peter Collinson had sent a gift of electrical apparatus to the Philadelphia Library Company in 1746, the same year Nollet startled his monks. The Library
21.The number of monks involved ranges from 180 to over 700, depending on which source you consult. The earliest published account, written by Joseph Priestley in 1767 (The His-tory and Present State of Electricity, with Original Experiments), doesn’t specify a num-ber, only the total circumference. It does mention a subsequent demonstration in front of the King himself, with 180 royal guardsmen (perhaps because willing monks were in short supply; word gets around). They jumped just as well as the monks.
Company had been Franklin’s project, and Collinson’s gift to the Company was, effectively, a gift to Franklin, who became so fascinated with the subject that he proceeded to purchase still more electrical devices (including the wondrous Leyden jar). He read everything he could on the subject, and soon Franklin knew as much about electricity as any expert. When he got around to the writings of du Fay, he was struck by the inefficiency of the two-fluid theory. He felt that a single fluid the-ory could explain things at least as well. Instead of vitreous and resinous electricity, perhaps all electrical phenomena could be understood as due to a surplus or defi-ciency of a single entity. Abbé Nollet, a strong proponent of his countryman’s two-fluid theory, at first refused to believe that the single-fluid theory could have come from a place as backward as America. He assumed that it was a joke contrived by his detractors on the Continent. Once he discovered that there really was a Ben-jamin Franklin in Philadelphia who had recently taken up the study of electricity, Nollet set about to craft learned rebuttals to the upstart’s proposals.
In 1750, Franklin proposed the experiment for which he is most famous. As had others, Franklin suspected that lightning was electrical in nature, but clear proof
was lacking.22 He devised an experiment to settle the question once and for all. The description of his proposal has been mangled in so many ways by so many sloppy authors that it is best to let Franklin speak for himself:
On the top of some high tower or steeple, place a kind of centry-box [sentry-box] big enough to contain a man and an electrical stand. From the middle of the stand let an iron rod rise and pass bending out of the door, and then upright 20 or 30 feet, pointed very sharp at the end. If the electrical stand be kept clean and dry, a man standing on it when such clouds are passing low, might be electrified and afford sparks, the rod drawing fire to him from a cloud. If any danger to the man should be apprehended (though I think there would be none) let him stand on the floor of his box, and now and then bring near to the rod the loop of a wire that has one end fas-tened to the leads, he holding it by a wax handle; so the sparks, if the rod is electri-fied, will strike from the rod to the wire, and not affect him.
Note that he makes no mention of trying to get lightning to strike the apparatus. His proposal describes an arrangement for drawing sparks from storm clouds that have not yet generated lightning strikes. Moreover, he describes how the observer is to be insulated, and even offers advice how to reduce the risk still further.
22.It should be obvious that Franklin did not “discover electricity,” as too many textbooks state. Who’s writing these things, and why do they get paid?
On 20 May 1752, this experiment was performed, but not by Franklin. Thomas-François d'Alibard had translated Franklin’s proposal into French, and the scientific community there quickly resolved to see if the American was correct. Under d’Ali-bard’s instructions, a 40-foot high pointed iron bar was erected in the middle of a garden at Marly-la-Ville in St. Germain. The bar was kept insulated from the earth. This insulation included the supporting lines, which were isolated from the earth through empty wine bottles (mais bien sûr! — see Figure 10). A storm cloud pass-ing by produced the predicted effect, allowing sparks to be drawn from the insu-lated bar. News of this success swept the Continent, and the experiment was soon repeated in many places. Overnight, Franklin became the scientific hero of the Enlightenment. But Franklin didn’t know it.
FIGURE 10. Franklin’s “sentry-box” experiment, carried out by the French
Franklin himself finally got around to running a version of the experiment on the 15th of June. He had been waiting for the completion of a spire at Christ’s Church in Philadelphia, but construction was progressing slowly. Tired of waiting, he improvised an alternative, using a kite to carry a conductor to great heights. With his 21-year old son William assisting, Franklin flew his famous kite in a storm, and
From Expériences et Observa-
tions sur l’Electricité, trans. by d’Alibard, 2nd ed., vol. II, 1756.
waited.23 After a time, they noticed the free fibers of the hemp twine suddenly stand out. When the twine was wet from the rain that was now falling, it became a good enough conductor to allow Franklin to draw sparks from a key tied to the
twine.24
Again, it’s important to stress that there was no lightning. Franklin had correctly reasoned that it takes clouds a fair amount of time to develop a sufficiently large charge imbalance to produce a lightning strike. His experiment was designed to detect that charge imbalance well in advance of a strike. Nonetheless, flying a kite in stormy weather is extremely dangerous, and you should not even think of attempting to replicate Franklin’s experiment.
Franklin’s pointy conductor is still used today as a lightning rod. The only differ-ence between it and the sentry box setup is that the rod must be well connected (electrically speaking) to the earth, rather than insulated from it. Contrary to wide-spread misunderstanding (and common linguistic usage) the rod is not intended to work by attracting lightning to itself, in the manner of a sacrificial target. Rather, its job is primarily to drain off the built-up charge (or, if you prefer, to restore charge balance), precisely to prevent lightning from striking in the first place. Of course, as with virtually everything else in life, lightning rods are not 100% effective, but they do significantly reduce the occurrence of lightning strikes. Franklin had proposed the lightning rod before his Philadelphia experiment, but the Royal Society in England found it too far-fetched to take seriously. After the French demonstrated that Franklin knew what he was talking about, the Royal Society made a rapid about-face and elected Franklin a Fellow of the Society. Lightning rods soon became common adjuncts to buildings, saving countless structures and lives from lightning-induced fires.
23.Paintings and other depictions of the experiment invariably show William as a young boy, not the man of 21 that he was. Perhaps it is artistic license, with a young William repre-senting universal childlike curiosity. Or perhaps it’s just another instance of sloppy fact-checking.
24.Occasionally, some doubt is expressed over whether Franklin actually carried out this experiment (there are books dedicated to the debunking of what is alleged to be the kite myth). William was the only witness, and Franklin himself did not write anything about it. The earliest account comes from Joseph Priestley, written about 15 years after the fact, after a correspondence with Franklin. The letter from Franklin is written in the style of how-to instruction, rather than a description of an event, leaving some room for contro-versy. Perhaps it is relevant to note that, despite a famously painful estrangement of father from son as the two supported opposite sides during the American Revolution, William never uttered a word suggesting that the experiment didn’t happen.
The painful experiences of the Leyden team had hinted at the dangers of electricity, but the whimsy of Nollet’s jumping monks may have lulled some into underesti-mating the risks. Regrettably, Georg Wilhelm Richmann of St. Petersburg became the first to show that the dangers were very real. On 6 August 1753, during an investigation of lightning inspired by Franklin’s accounts, Richmann and one M. Sokoloff (an engraver brought along to document his discoveries) were observing an electrical “gnomon” devised by Richmann. The device was a primitive voltme-ter designed to provide a quantitative measure of the electrical pressure induced by a passing storm. While they huddled close to the device, lightning struck, instantly stunning Sokoloff into unconsciousness. When he awoke, he saw that Richmann was dead. A small spot of blood on his forehead was all that marked where light-ning had entered the recently departed professor. More dramatically, his left shoe had been blown off where the lightning had exited, with his foot much worse for the wear. Moral: Don’t try this at home, even if you are a professional.
Sidebar: Franklin’s polarity “error”
Franklin replaced vitreous with positive and resinous with negative. So great was his influence that the older terms were permanently displaced almost overnight. Unfortunately, state countless textbooks, Franklin made a mistake in assigning those polarities. However, polarities are arbitrary, so it is hard to see how one could ever be “wrong” in selecting one convention or the other. It’s as if someone were to assert that left and right had been assigned incorrectly long ago. As long as one sticks consistently with a choice once it’s made, there is no fundamental problem. However, Franklin did indeed make a mistake: His single-fluid theory is wrong. It is true that in ordinary conductors, electrical current results solely from electron motion. In those cases, a single-fluid theory explains phenomena well. However, there also exist positively charged entities, such as protons, positrons (anti-elec-trons), and positive ions. These can also move, and therefore can constitute an elec-trical current. This consideration is hardly esoteric, for an ordinary flashlight battery depends on the motion of ionic species for its operation. So, too, does your nervous system. Thus, strictly speaking, du Fay was correct, and Franklin was wrong. There really are two kinds of electrical “fluids.”
The idea that lightning could have anything in common with the feeble sparks gen-erated by friction machines intrigued everyone. The experiments by d’Alibard and Franklin showed that these were indeed manifestations of a single phenomenon. Still, it was natural enough to ask whether the output of friction machines could be increased enough to make this case even more convincing. The Dutch scientist Martinus van Marum designed a huge generator in 1784 that was ideal for this pur-pose. The machine consisted of two parallel rotating glass disks (basically, a
Hauksbee-like design on steroids, with disks replacing globes), each 165cm in diameter, mounted 20cm apart on a single meter-long axle. With this enormous fric-tion machine, van Marum produced sparks up to about 65cm in length, correspond-ing to an estimated 300kV!
FIGURE 11. Replica of van Marum’s machine (note the bank of Leyden jars)
Franklin undoubtedly would have been most impressed by van Marum’s generator. Whether he was aware of its existence is unknown, however. He never commented on it in any known correspondence, but that’s hardly surprising, given that he was somewhat busy with other matters, such as establishing a new government after fighting a revolutionary war.
It’s alive!
While van Marum was considering preliminary designs for his mammoth genera-tor, and Franklin was working deft diplomatic magic to win the sympathy of a monarchical France toward a republican revolution, Luigi Galvani was performing some routine dissections of frogs in his laboratory at the University of Bologna’s
medical college.25 It was a dry November day in 1780 and the bracing air cut through his laboratory just as Galvani cut into a frog’s leg with his scalpel. To his
utter shock the leg kicked. He was puzzled that this phenomenon was only intermit-tently repeatable. Investigating further, he discovered that the kicking occurred only when the leg was on a metal plate while the scalpel was touching a relevant nerve. The conclusion was inescapable: Electricity caused the jumping. A dead frog’s leg kicks just as if it were alive, thanks to electricity. Galvani could hardly contain his excitement. Had he found the secret of life?
Galvani soon discovered that asking the question was a great deal easier than answering it. The lack of a good theoretical framework meant that most of his experiments would yield null or confusing results. Plus, he had more than a full time job in his classes to teach, a busy medical practice to run (including much charitable work for the poor citizens of Bologna), and the many laboratory demon-strations he had to prepare and present. His electrical research progressed slowly.
FIGURE 12. Luigi (Aloisio) Galvani
Somewhere along the way, he understood that his frog legs could be used as electri-cal indicators. His ignorance of how they worked was secondary to the fact that the frog legs were exquisitely sensitive. Where Franklin had to draw sparks, Galvani
25.He was born Luigi, but preferred to be called Aloisio (after his patron saint). Different biographical sources call him by one name or the other, leading to some confusion.
only had to observe some twitching. No one could have known then that, had Gal-vani combined his frog legs with van Marum’s giant generator, the age of wireless communications could have begun a century earlier than it did. True, such a devel-opment would have been bad news for frogs, but that’s only a problem if you’re a frog.
Once Galvani got the idea of using frogs as electrical indicators, he reasoned that their highly sensitive legs would allow him to detect electricity in nearby storm clouds without d’Alibard’s 40-foot pointy iron bar, or Franklin’s kite. And so one fine blustery October day in 1786, Galvani took some frog legs up to the roof of his building and hung them on an iron railing, using hooks that happened to be made of copper. Then he sat, waited and watched. Just as he had hoped, he eventually observed twitching. He was surprised, though, that no storm clouds were yet visi-ble. Could frog legs be that sensitive? As he continued his observations, he realized that the frog legs twitched whenever a passing breeze happened to blow them against the iron bars of the railing. He forgot all about d’Alibard and Franklin, and went back downstairs to study this new finding. The twitching obviously couldn’t have anything to do with lifeless copper and iron, and so he concluded that “animal electricity” was the cause of the twitching. More than ever, he felt he was on the threshold of unlocking the very secrets of life.
He published the culmination of eleven years of research in 1791, as part of a mul-tiple-volume set of the local Institute of Science’s memoirs. His contribution was such a sensation that it was excerpted and reprinted as a separate monograph. Twenty-five years later, Mary Shelley would be inspired in part by Galvani’s dis-
coveries to pen Frankenstein.26 Galvani was famous. More precious to him was that he was beloved by his family, by the many grateful poor whom he treated for free, and by his students. Life was good for the 54-year old doctor.
It’s not alive!
Alessandro Volta was one of many scientists who had been following Galvani’s work with great avidity. Volta was a young professor at the University of Pavia, and initially agreed with Galvani’s declaration that lifeless copper and iron could not give rise to the twitching. The animal electricity theory seemed as obviously correct
26.Despite the depictions of Hollywood versions of Frankenstein, Shelley makes no explicit mention of electricity animating the monster of her novel.
to him as it had to Galvani. But as he ran his own experiments, doubts emerged. If, as Galvani was arguing, the “life force” that drove the twitching resided solely in the frog leg, why were two different metals always required? It dawned on him that the metals were essential to the phenomenon, not merely incidental. Volta began to publish a series of increasingly critical rebuttals, and the two men became adversar-ies.
International politics then intervened. Napoléon Bonaparte’s army “liberated”
Bologna and other regions in 1797 from the alleged tyranny of Austria.27 The gov-ernment of the Cisalpine Republic established by Bonaparte required all state employees, including university professors, to swear allegiance to it. Galvani defi-antly refused, and was summarily dismissed from the University. He hoped to com-pensate for the loss of salary with income from his medical practice, but his patients had never been the wealthy Bolognese, and the political turmoil only made things worse. Galvani suffered poverty for the first time in his life. Worse, the professor of medicine was powerless to help his beloved wife when she fell seriously ill. Her death shattered him. He was eventually allowed to return to the University despite his earlier refusal, but this small bit of good news hardly mattered. He followed his wife in December of 1798.
Volta fared much better. He was apolitical — a nerd, really. A gentleman to be sure, but a nerd nonetheless. As long as he was free to carry out his research, he didn’t particularly care who was in charge. In keeping with the spirit of the times, he developed a convenient amnesia that his grandfather had been a count, and so was perfectly happy now to be Citizen Volta. Thus unencumbered by politics, Volta pro-ceeded to study Galvani’s “pretended animal electricity” in detail. As the snideness evident in that reference clearly shows, Volta had come to believe with certainty that the electricity came from the combination of dissimilar metals. Biology had nothing to do with it. The challenge was to prove it.
He recognized that he would have to invent an electrical indicator that was compa-rable to a frog leg in sensitivity, but constructed out of non-living materials. His solution was an ingenious improvement over existing devices. He bent a thin piece of straw into a V-shape, and suspended it upside-down on a conductive pivot. Any charge deposited onto the straw through the pivot connection would cause the two
27.Within a few years he would declare himself Emperor, enraging Beethoven, who had originally planned to dedicate his Third Symphony to Bonaparte the liberator. Tearing up the dedication page, Beethoven renamed the symphony the more generic Eroica, the name by which it has been known ever since.
arms of the V to repel. The angle they formed would be a measure of the amount of
charge deposited.28 Figure 13 shows an actual electroscope used by Volta. An elec-trical connection to the pivot is made through the brass terminal on top.
Now came his coup de grâce.29 He put two dissimilar metals together (copper and zinc plates, in his first experiment). If his theory was correct, the mere contact of these two metals would leave one with a net positive charge, and the other with a net negative one. He wasn’t concerned about the polarity at this point; all he cared about was the “net charge” part of the phenomenon. He picked up one of the plates with an insulated tool, and placed it in contact with the electroscope terminal. He put the plate back into contact with its mate, and then touched the electroscope with it again. After several iterations, he could see that the straw arms were indeed mov-ing apart.
FIGURE 13. Volta and his straw electroscope
Volta’s experiment showed convincingly that dissimilar metals in contact would produce electricity. It was therefore unnecessary to postulate some magical “animal
28.Once again, what we mean by “deposit charge” is really “displace charge.” 29.Pronounced “coo de grahss,” not “coo de grah.” The gras in Mardi Gras is pronounced
electricity” to explain what Galvani saw. He came to these conclusions in April of 1798, when a dispirited Galvani would no longer have cared.
Although his definitive dismissal of animal electricity was impressive and estab-lished his reputation as a first among equals, Volta’s crowning triumph was yet to come. Having proven that “contact electrification” was a fact, he reasoned that it should be possible to intensify the effect by using multiple elements in a stack. He found that mere contact between two metals didn’t work very well, although it had served well enough for the animal electricity experiment. Further experimentation revealed that using a fluid to couple the two metals worked much better. The basic repeating cell consequently consisted of a copper and zinc disk, with a brine-soaked piece of felt in between. In 1800 he assembled a great many of these cells in a col-umn (pila, in Italian). When his report was translated into English, people referred to his device as a Voltaic Pile. Today we call it a battery.
The “pile” was revolutionary because it was the first steady source of electricity. You didn’t have to spin or rub anything. It was cheap and easy to build, and the “electrical pressure” could be adjusted readily by changing the number of cells in the stack. Not surprisingly, Volta’s pile soon became an indispensable piece of lab-oratory equipment the world over. With it, one could easily excite frog’s legs, melt small quantities of metals, and repeatedly deliver both non-lethal and lethal shocks. Although the underlying details of its operation were not yet fully understood, the mere fact of its existence set the stage for the key developments of the 19th century. The telegraph, telephone, electric motor, electric light and wireless communication were just around the corner. The modern age of electricity was dawning.
In recognition of these achievements, Bonaparte made Volta a Count in 1810, and in 1881, the international physics community named the electrical unit, the volt, in his honor.
True to form, Volta weathered Bonaparte’s downfall with grace. He seized the opportunity to retire to an estate near his birthplace of Como, as he’d always dreamed. He lived there to the ripe age of 82, enjoying his retirement years as a gentleman farmer. The Tempio Voltiano, a museum dedicated to honoring his work, was built near Lake Como in 1928 to house his original papers and instruments, and
remains a popular tourist destination for nerds of all ages.30
30.The original plan was to open the Tempio in time to celebrate the centennial of Volta and his pila. Unfortunately, the whole place burned down in 1899, just before its public dedi-cation. The vast bulk of Volta’s original papers and instruments were lost in an instant. It took almost 30 years to locate the few surviving artifacts scattered over the globe, recon-struct others, and rebuild the museum.
Now let’s take a look at that legend of Thales and amber. The earliest known refer-ence to an amber effect is found in Plato’s Timaeus:
... marvels that are observed about the attraction of amber and the Heraclean
stones... c. 360 BCE; translation by Benjamin Jowett
Aside from having been written a quarter-millennium after Thales, note that the quotation conspicuously fails to mention the man at all. Plato does mention “Hera-clean stones,” an alternative term for lodestones, named for a region rich in mag-netic ore. Such ore is also found in Magnesia (home of the mythical characters Jason and Achilles; the modern city of Volos is near the center of that ancient pre-fecture of Thessaly), and the name derived from that region eventually prevailed,
giving us the word magnet.31 The area’s mineral wealth extended to magnesium ore as well, whose name is even more directly derived from the region’s name.
Note also that Plato makes no distinction between the amber effect and magnetism.
Other authorities occasionally cite Aristotle but, in all of his extant writings, there is just a single sentence linking Thales with magnetism:
Thales, too, to judge from what is recorded about him, seems to have held soul to be a motive force, since he said that the magnet has a soul in it because it moves the iron.
— De Anima (On the Soul); c. 250 BCE; translation by J. A. Smith
That sentence, written 350 years after Thales — a century after Plato — is indirect at best (“.... from what is recorded about him...”). And instead of describing a dis-covery, it reads as if Thales were invoking an already-familiar phenomenon to present a logically dubious proposition about souls.
In some other cases, one encounters citations of writings by Theophrastus (Aristo-tle’s favorite pupil and successor), or much later ones by both Pliny the Elder and
31.Although Plato preferred Heraclean stones, in Ion he cites Euripides’ use of magnetis, around 450 BCE. It should also be mentioned that other ancient cities in that general part of the world were also named Magnesia, so there is some disagreement among authorities about which Magnesia gave rise to the word.
his nephew, Pliny the Younger. The Elder was a Roman naturalist who, among other works, wrote a 37-volume encyclopedia of natural history (it has survived intact to the present day). He died (apparently from some sort of respiratory dis-tress) while observing Mount Vesuvius during the early hours of its famous erup-tion in 79 CE. The Younger’s eyewitness account of the eruption itself (from a safe
30 km away, across the Bay of Naples) makes for thrilling reading.32 Voluminous as they are, their collective writings also do not provide any accounts of relevant discoveries by Thales. So where does the amber legend come from?
Diogenes Laertius, in a somewhat gossipy (thus popular) and certainly unreliable biography of philosophers, gets around to adding a brief reference to “the amber effect” in connection with Thales, some 600 years after Plato’s magnet reference (again, in a single sentence):
But Aristotle and Hippias say that he [Thales] attributed souls also to lifeless
things, forming his conjecture from the nature of the magnet, and of amber.33
— The Lives and Opinions of Eminent Philosophers; c. 250 CE; translation by C. D. Yonge
It is unfortunate that nothing of Hippias has survived, for the sentence still does not describe a discovery. Moreover, the brevity of that quotation perhaps suggests something of the importance attached to it. Its length certainly stands in contrast to that of some of his other stories about Thales:
Some assert that he was married, and that he had a son named Cybisthus; others, on the contrary, say that he never had a wife, but that he adopted the son of his sister; and that once being asked why he did not himself become a father, he answered,
32.Pliny the Elder is also responsible for popularizing an “explanation” of the origin of Mag-nesia and magnet. In Book 36, paragraph 127 of his Historia Naturalis he cites the Greek poet Nicander’s tale of a shepherd named Magnes, whose sandals (actually, the iron nails holding them together) stuck to an outcrop of rock in the fields atop Mount Ida. The Younger was always amazed at how much his uncle could write, but we now know part of the secret: He either just made things up or passed along stories from others without both-ering to investigate further (hint, Mr. Pliny: Nicander was a poet, as in “not a historian.”). Fact-checking only slows you down. It’s no wonder that the Romans contributed almost nothing of fundamental value to science and mathematics.
33.There is even an unresolved question among scholars about whether the amber reference was added later by another writer. As with Plato’s quotation, this one makes no distinc-tion between the amber effect and magnetism.
that it was because he was fond of children. They say, too, that when his mother exhorted him to marry, he said, “No, by Jove, it is not yet time.” And afterwards, when he was past his youth, and she was again pressing him earnestly, he said, “It is no longer time.”
In any event, subsequent authors greatly embellish the slim tidbits from Aristotle and Laertius to credit Thales with having first observed the amber effect. Notably, however, Thales is nowhere in Gilbert’s thorough historical review, so we are left to conclude that the now-popular story takes hold after the year 1600. It’s indeed amazing how so much has been made out of so little, and how difficult it is to cor-rect an error once in print.
Volta’s pila revolutionized electrical research by lowering the barrier to participa-tion. This inexpensive, versatile and steady source of electrical power greatly accel-erated the rate of discovery simply by making it easier for more people to perform experiments. Suddenly, it was possible for just about anybody to get into the act. What had recently been almost exclusively a wealthy gentleman’s recreational pas-time suddenly became an obsession for nerds of all backgrounds. The battery liber-ated the inner geek as it democratized research.
This liberation succeeded in spite of a minor embarrassment, however: The battery did not quite work according to the principles that led to its invention. Recall that Volta had offered “contact electrification” as the explanation for Galvani’s kicking frog legs and his own electrometer indications. Although that remains the accepted explanation for at least part of those observations (even though some doubts persist about the details), his leap to the battery required the somewhat arbitrary addition of a fluid. It was appreciated only later by others (especially by the remarkable Michael Faraday, whom we’ll meet shortly) that the fluid is by no means an inci-dental convenience for maximizing the effective contact area. Rather, the fluid (now known as the electrolyte) actively participates in chemical reactions that ulti-mately produce the electrical output. When the reactants have been consumed, the battery stops working. Thus the battery does not produce energy forever from the mere static contact of two dissimilar metals, as implied by Volta’s original explana-tion; no magic is involved. Instead the electrical energy comes from the release of
energy already stored in chemical bonds, and is therefore finite. That there is no free lunch is perhaps the most fundamental of the physical laws, and the battery is
sadly no exception.34
None of these developments bothered Volta in the least, of course. By the time other scientists got around to asking these tough questions, he was enjoying his retirement years in Como, having long ago disengaged from the research that had brought him fame. And for the most part, others weren’t terribly bothered, either. The battery worked, Volta was a nice guy, and that was enough for many. For the few who did care about the mistake, the error simply gave them another enjoyable puzzle to solve.
One of the many scientists excited by Volta’s marvelous invention was Hans Chris-tian Ørsted (Oersted). The Dane was a disciple of the philosopher Immanuel Kant, whose musings Ørsted distilled down to the idea that “all phenomena are produced
by the same power.”35 For Ørsted, the belief in a unified theory of everything was more than an abstract philosophical notion. It was a profound organizing principle, a reductionist lens through which he perceived the world. He saw the pila as a means for validating his beliefs about the nature of nature.
As did his contemporaries, he knew that electricity and magnetism individually exhibited attractive and repulsive behaviors. Furthermore, he was well aware, as were most good scientists, that iron rods were sometimes found magnetized after nearby lightning strikes. Although Franklin himself had expressed skepticism about
any direct link, Ørsted ignored those doubts.36 He chose instead to regard those observations as further evidence that electricity and magnetism were indeed merely different aspects of a more fundamental “power.”
Despite his belief, and despite having all of the necessary apparatus at his disposal, it took a surprisingly long twenty years before he succeeded in proving it. In his
34.The principle of energy conservation was not yet a foundational tenet of science, although many researchers had learned life’s lessons and thus had gained an intuitive understand-ing that one could not expect something for nothing.
35.This saying became Ørsted’s oft-uttered credo.36.Franklin felt that the most probable explanation was that lightning heated these iron
objects to a high enough temperature that, upon cooling, they would be spontaneously magnetized by the earth’s magnetic field. His theory explained many inconsistencies, including why some rods actually became demagnetized after a lightning strike. Franklin was a very good scientist!
defense, he spent much of that time engaged in many other activities, including an intense study of chemistry, as well as chasing after tenured faculty positions. Fail-ing in the latter endeavor, he settled for earning a living as a lecturer, and quickly became one of the most popular teachers at the University of Copenhagen. He was so busy with these other activities that he apparently didn’t get around to undertak-ing his unification experiments in earnest until around 1816. The basic setup he contrived was simplicity itself: A battery, some wire, and a compass. He reasoned that a current in the wire ought to generate magnetism. On one occasion in the win-ter of 1819, he chose to perform an experiment with his apparatus in front of a group of students.
In his own words, here’s what happened:
The magnetical needle, though included in a box, was disturbed; but as the effect was very feeble, and must, before its law was discovered, seem very irregular, the
experiment made no strong impression on the audience.37
Translation: He thought he saw something, but no one else did.
37.From an entry by Ørsted on thermoelectricity for the Edinburgh Encyclopaedia, 1830. The years it took to find a link between electricity and magnetism (when he was allegedly actively seeking one) soon gave rise to suspicion that his discovery had been a total acci-dent. After all, if you hand a battery, some wire, and a compass to some reasonably bright students, they will generally stumble across the relevant effect in less than an hour (I’ve actually run this experiment with 5th-graders). It’s almost impossible not to discover it, in fact. Perhaps the most charitable interpretation is that Ørsted’s stubbornness led him to repeat only a limited set of experiments that were unfortunately doomed to fail. Then he got lucky. His inability to understand subsequently developed mathematical descriptions of his discovery has left him vulnerable to less generous views. The most popular version has Ørsted demonstrating the heating potential of electrical current, when a nearby com-pass needle deflects, demonstrating an effect that he hadn’t been searching for. Like the Thales myth, this story has been retold so many times (by none other than J. C. Maxwell himself, for one) that it has acquired the status of fact. However, it’s important to keep in mind that the ambiguity of the available sources neither confirms nor rules out the “damn lucky professor” hypothesis.
He could hardly declare success on the basis of such an ambiguous result. If he couldn’t impress his own students — students who liked him, no less — it was unlikely that he’d impress anyone else. He needed an unequivocal demonstration.
He met with failure after failure. The compass needle either stubbornly refused to budge at all, or moved so slightly or unpredictably that he couldn’t draw any con-sistent conclusions. Despite these frustrations, he stubbornly held to his belief that the experiment should work, and persisted long past when others would have given up. At one point he began wondering whether his battery was capable of providing enough current (whatever enough might be), so he built a much larger pile in the spring of 1820. As he’d done many times before, he placed a wire near his trusty compass, then closed a switch. The needle rotated by a definite amount at last. The powerful Voltaic pile produced a noticeable effect even though he had oriented the
wire and compass incorrectly, as apparently on virtually every previous occasion.38 In cartoon form, his experiment looked like this:
38.If we are inclined to grant Ørsted the benefit of the doubt, the more powerful battery helped to compensate for excessively thin wires, and for incorrect orientation of the com-pass. He apparently believed that large wires would tend to mask the effect he was seek-ing, so he initially used very thin wires. Unfortunately, these have high resistance, which reduces current. In turn, a reduced current corresponds to a reduced magnetic force. Wrong placement of the compass — based on his not unreasonable expectation that the magnetic force should be aligned along the direction of current — made things even worse. In brief, he evidently worked overtime to stack the deck against success. Fortu-nately, his persistence gave luck enough time to prevail.
With the switch in the open position (as in the left drawing), no current flows, and the compass points north (here drawn as toward the right). With the switch closed, current flows, and the wire exerts a magnetic force. That force rotates the compass needle, pushing it to align more or less orthogonally to the wire. It is thus a peculiar force, as it pushes at right angles to the direction of the electrical current that pro-duces it. Undoubtedly, this unexpected behavior contributed to Ørsted’s long delay in discovering it. By carefully orienting the compass to look for deflections in the “normal” direction, he may have cleverly designed many of his experiment to fail.
Ørsted was gratified at the fulfillment of his Kantian quest, even if he was puzzled by several aspects of the artificial magnetism he generated. He was particularly sur-prised that the compass needle pointed one way when above the wire, but the oppo-site way when below it. It appeared that the magnetic influence circled the wire, in addition to its orientation at right angles to the current flow. Magnetism was even more perplexing than he’d originally found. He spent a couple of months running additional experiments and double-checking his results, just to be sure. Finally, he felt confident enough to reveal to the world what he had discovered. On 21 July 1820 he sent off a four-page letter to scientific societies throughout Europe (and to selected individual scientists as well). It was an instant sensation, much like d’Ali-
bard’s verification of Franklin’s conjecture so many years before.39 Ørsted won a
39.Some sources spuriously credit Gian Domenico Romagnosi with having anticipated Ørsted, citing newspaper reports dating to 1802. Romagnosi may have been a fine law-yer, but he was no scientist. His experiment involved no current flow at all; his reports of a compass needle being deflected therefore cannot in any way be construed as evidence of beating Ørsted to the punch. His work should remain just a footnote. Like this one.
permanent faculty position at last, and lived the remainder of his life a much beloved figure of Danish science.
FIGURE 17. Danish postage stamp honoring Ørsted
On 4 September 1820, Ørsted’s discovery was formally reported to the French Académie des Sciences. The news astounded and excited everyone present, but
none more than the brilliant and eccentric André-Marie Ampère.40 Electromagne-tism instantly became the latest in a series of obsessions that insulated him from tragic memories.
Ampère was born in 1775 in a small village with a long name. Polémieux (Poley-mieux)-au-Mont-d'Or was a quiet hamlet near Lyon in central France. It had no school, so Ampère was taught by his doting father. Either the teacher or the student was very good for, by the time he was a young teen, Ampère was amazing acquain-tances with prodigious powers of calculation, and with his ability to recite from memory long entries from an encyclopedia. He spent the days happily drinking in knowledge from a great variety of fields. The French Revolution abruptly ended this idyll when Ampère was a young man of 18. It was his family’s misfortune that the Lyonnaise were among those who actively resisted the Revolution. In the orgy
40.His countryman and scientific Big Shot Charles Augustin Coulomb believed that electric-ity and magnetism were so different that there could not possibly be any link between them. Coulomb’s stature was such that his opinion carried considerable weight. Thus, as Ampère would later ruefully relate, the French failed to discover the link between elec-tricity and magnetism for the simple reason that no one in France was looking for one. That is one reason why the reaction to Ørsted’s discovery was particularly extreme in France.
of violence that followed Lyon’s inevitable fall, Ampère’s beloved father — a busi-nessman and minor city official — was found guilty of trumped-up charges and sent to the guillotine. The death of his father drove the poor son mad with grief. For the next couple of years, the inconsolable Ampère was scarcely able to speak, and he wandered aimlessly about Lyon and environs, a pathetic figure. He gradually recovered after a fashion and immersed himself obsessively in the subject of bot-any. At 21, during one of his many self-assigned field studies, he happened upon a young woman, Cathérine-Antoinette (“Julie”) Carron, and miraculously began a romance with the gentle Julie. Her father was understandably concerned with his daughter’s seemingly unstable choice, and insisted that Ampère prove himself by securing gainful employment before marriage could even be discussed. After show-ing his ability to attract a great many lucrative tutoring jobs, Ampère married Mlle. Carron in 1799. A son, Jean-Jacques, was born the following year. Two years after that, Ampère won a position teaching physics and chemistry at l'École Centrale du Département de l'Ain (now the Lycée Lalande) in Bourg-en-Bresse, some 60km from Lyon. The distance was great enough in that era of equine transportation that he had to spend most of his time away from his young family in Lyon. Sadly, his wife fell ill and died a year later, in July of 1803. The survival of his young son (who would later enjoy academic success as a philologist) consoled him, but he never truly recovered from this second tragedy. He took another job, this time to teach mathematics, at l’École Polytechnique in Paris in 1804, soon married one Jeanne-Françoise (“Jenny”) Potot in 1806, had a daughter, Josephine-Albine, in 1807, and was divorced from Jenny by 1808. He hopped from mathematics to lan-guages to chemistry to various other topics. He approached each with such mania-cal intensity that one might reasonably speculate that he was trying to keep painful memories buried, more than anything else. A quiet mind is contemplative.
The announcement of Ørsted’s achievement virtually set Ampère’s already-busy brain aflame. In a marathon nerdfest he replicated all of Ørsted’s experiments, and derived important additional insights along the way. He presented his first report to the Académie on 18 September, just two weeks after hearing Ørsted’s news. He fol-lowed up with another on the 25th, and then, just one week after that, presented a comprehensive paper of almost 70 pages (sometimes, being obsessive-compulsive is a good thing). In effect, he had started and then completed a doctoral thesis in a month. Along the way, Ampère encountered an unexpected impediment: Extant vocabulary was simply inadequate to describe the subject in a clear and consistent manner. Following Shakespeare’s lead, he solved that problem by inventing new words as needed:
FIGURE 19. From first page of Ampère’s third report to the Académie41
A rough translation is as follows:
Report
Presented to the Royal Academy of Sciences on 2 October 1920, where is found the summary of that which has been read to the same Academy on 18 and 25 Septem-ber 1820, on the effects of electric currents.
By M. Ampère
1st: On the mutual action of two electric currents.
I. The electromotive action manifests itself as two sorts of effects that I believe ought to be distinguished at the outset by a precise definition.
41.Annales de chimie et de physique, 1820, vol. 15, pp. 59-74, and pp.170-218.
I will call the first electric tension, the second electric current.
The terms tension and current remain with us, although the former has been largely replaced by voltage in the United States. In any event, we have Ampère to thank for
explicitly separating and identifying these fundamental quantities.42 Just as water pressure and water flow are distinct, a voltage can exist without the flow of charge (without a current), and a current may exist without a voltage. The term current
flow is frequently encountered (but not in Ampère’s writings), but it’s another one of those linguistic oddities that understandably confuses the uninitiated. Because a current is already a flow (of charge), current flow is redundant at best, and mean-ingless at worst. But it’s common usage, so we use it commonly.
In his methodical study of the subject, Ampère not only provided a welcome verifi-cation of Ørsted’s results, but went well beyond them. Ampère showed, for exam-ple, that the magnetism surrounding a current-carrying wire behaves as that around
an ordinary magnetized material.43 In a dramatic demonstration of this equiva-lence, Ampère showed that two adjacent current-carrying wires exert forces on each other. If the currents are in the same direction, then the wires attract. If the cur-
rents are oppositely directed, the wires repel.44
This evident equivalence of “natural” and “artificial” magnetism emboldened Ampère to offer an answer to an ancient question: Iron, cobalt and nickel were then known to be magnetic, but no one could explain what made these metals special. In an age when the existence of atoms was at best a conjecture, Ampère made a daring intuitive leap from just a few experiments to postulate that magnetic materials derive their properties from microscopic electric currents within them. Instead of invoking Gilbert’s mysterious effluvia, he explained magnetism in terms of another, known physical phenomenon: electricity. He noted, as had Ørsted, that current-car-rying wires always generate a north and south pole together. As de Maricourt had
42.His influence was so great, in fact, that the modern symbol for current is I. Few engineers today (outside of France, perhaps) are aware of its origins in Ampère’s use of intensité to describe what we now call a current’s strength in amperes.
43.The concept and terminology of a field were as yet undeveloped. Instead, Ampère and his contemporaries used Ørsted’s term, electrical conflict, to describe the curious spatial dependencies of this magnetic force. The conflict, of course, was psychological, not elec-trical.
44.Indeed, this fundamental effect is today used as the basis for defining the force between charges, even if the charges are not flowing. Measurements based on such an indirect def-inition present fewer experimental challenges than does measuring the forces between charges directly.
reported centuries earlier, naturally occurring magnets always have two opposite poles as well, even if you break them into any number of pieces. The similarities were not lost on Ampère. However, other scientists immediately raised quite rea-sonable objections: Where were these currents? What drove them? How could they persist indefinitely? Ampère could not provide satisfactory answers to all of these questions (and in fact a comprehensive explanation would not be possible until the development of quantum mechanics, more than a century later), but today we know that his intuition was basically correct (at least generally, if not in detail). Specifi-cally we now know that atoms have electrons, and that these electrons may move
through the bulk of a material, “orbit” their host atoms, and also spin.45 All of these types of motion constitute electric currents capable of generating magnetism, but it is the latter property, spin, that is most important. In an ordinary, non-magnetic materials, spins are randomly oriented, and so the magnetism they collectively gen-erate averages to zero. But in certain special cases, the spins align, and a net magne-tism results.
Ampère later derived a quantitative relationship (now known, appropriately enough, as Ampère’s law) that describes the strength and direction of the magnetic force in terms of the current in a wire, and the distance from that wire. Ørsted, whose own strength was in chemistry rather than in mathematics, not only failed to understand Ampère’s achievement, but went so far as to make an uncharacteristi-
cally snide remark about the “clever French mathematician.”46 In any case, Ørsted made essentially no further contributions to the subject.
Even with Ampère’s substantial contributions, Ørsted’s program for a Kantian uni-fication of forces was incomplete, but Ørsted himself seemed not to notice or care. His discovery of electromagnetism showed a definite link between electricity and magnetism, to be sure (as reflected in the very word electromagnetism), but he left unanswered an important question for others to ponder: If all forces derived from a common power, shouldn’t magnetism be able to produce electricity? The answer to
45.This type of spin is a quantum-mechanical property, and therefore the image usually evoked by the word is grossly misleading. An electron, as far as we can tell, is a point particle with no sub-structure, and points can’t spin. But an electron exhibits angular momentum nonetheless, so physicists gave this property the name spin. To avoid confu-sion they probably should have called it something totally unevocative of a familiar phe-nomenon, like “numberwang,” but alas...
46.The actual quotation translates roughly as “The shrewdness with which the clever French mathematician has shown little by little to convert and develop his theory in such a way that it lets itself unite with a multitude of conflicting facts, is peculiar.” (Many thanks to Marit Kleveland Ardila for the translation!)
that question would ultimately lead to motors, generators, industrial power plants, disk drives in computers, and wireless communication, to name but a few exam-ples. In short, the answer would teleport humanity to a new universe, beyond the fantasies of even the most creative literary lights.
Davy and Faraday
The race to answer that question would be won by a most unlikely genius. Dicken-
sian poverty is perhaps the most succinct, poignant way to describe the circum-stances of Michael Faraday’s early life. Even the anomalous Stephen Gray, poor though he might have been, was well off compared with young Faraday. There were times when the family Faraday could manage only a single loaf of bread a week for the boy.
Apparently, man can live by bread alone — at least for a time — for Michael made it to the age of 13 in sufficiently good health to begin an apprenticeship with a Lon-don bookbinder named George Riebau, in 1804. Riebau was a kind fellow who, noticing early on that Faraday was at least as interested in reading books as in bind-ing them, allowed young Michael to read customers’ books after hours. With the finest volumes of London’s elite thus at his disposal, Faraday eagerly gave himself a first-class education in a variety of subjects. The overused phrase “voracious reader” definitely applies to him, as understatement. Books on science were his favorite, and he devoured them all. He used what little money he could spare to pur-chase a few materials to carry out simple experiments of his own. He even formed a club with a few like-minded young nerds to share in this newfound hobby. Alone or together with his fellow club-members, Faraday would attend public lectures when he could, always taking careful notes, and then working on them afterwards, adding illustrations and examples. Riebau was impressed, even if he didn’t quite under-stand what Faraday was doing.
In February of 1812, when the 20-year old Faraday was nearing the end of his apprenticeship, Riebau showed some of these notes to a customer named William Dance (a co-founder of the Royal Philharmonic Society). Dance was duly impressed and handed Riebau tickets for Faraday to attend a series of public lec-tures by the great Humphry Davy, who was a “rock star” chemist, sometime poet, frequent substance abuser (he synthesized nitrous oxide — “laughing gas” — and used it recreationally), sex symbol and spellbinding speaker. Faraday attended Davy’s four lectures at the Royal Institution in March and April with a focus that
went beyond avidity.47 He took copious and careful notes as he listened to every word in rapt attention.
FIGURE 20. Humphry Davy
Davy described how he’d used an incredibly powerful battery of his own design to decompose (“electrolyze”) certain compounds into apparently fundamental constit-uents. Using language not then in vogue, we can say that passing an electric current through certain liquid compounds can force ions in solution to deionize and become atoms. With this method, he became the first to isolate sodium and potassium, among other achievements. Thanks to Davy, these substances were now understood to be elements. Davy was using Volta’s pile to probe the very structure of matter
47.The Royal Institution, not to be confused with the Royal Society, was founded by Ameri-can scientist and arms dealer Benjamin Thompson, who fought on the side of the British in the Revolutionary War. As Count Rumford, he married Lavoisier’s widow and estab-lished, with Sir Joseph Banks, the Institution on the premise that subjecting London’s poor to science lectures would improve their lot. Predictably, the poor stayed away in droves. It quickly evolved into a gathering place for London high society. One of Davy’s friends, Samuel Taylor Coleridge, was frequently in attendance, for example. It became the place to see and be seen.
itself. The invisible was no longer inaccessible. Ultimate Understanding was within grasp!
Faraday was spellbound. After returning home, he expanded, edited and bound his notes. In a bold move, he presented the volume to Davy himself, along with a letter informing the great Davy that the humble Faraday would be available for any task. Davy had nothing for him at the time, but thanked him graciously, offering that it might be possible someday to arrange for the bookbinding business of the Institu-tion to be given to Faraday. And that was that for a while.
Some months later, in October, Davy was temporarily blinded in a chemical explo-sion (always wear safety goggles in the lab). Needing an assistant with a technical background and excellent note-taking skills, Davy called on Faraday, who jumped at the chance and performed brilliantly. Although Faraday had to leave after Davy recovered, fate intervened a second time. The Royal Institution’s laboratory assis-tant was dismissed after a row with another Institution employee. Davy saw to it that Faraday was offered the salaried, full-time position. Faraday began what amounted to a second apprenticeship, in chemistry, on March 1, a few months shy of his 22nd birthday in 1813.
The next several years were heaven for Faraday. He served as Davy’s research assistant in the laboratory and as factotum on his European travels. Faraday could scarcely believe his good fortune. That Davy’s wife, Jane, refused to allow some-one of Faraday’s low station to dine with them bothered him not at all. Faraday’s Sandemanian humility would not allow him to take offense. To the contrary: He was deeply grateful to Davy for a chance at a life in science.
FIGURE 21. Portrait of Faraday as a young scientist
Faraday was such a quick study that he rapidly shifted from mastering the state of the art, to defining it. Davy initially took great pride in his prodigy’s achievements (“Davy’s greatest discovery may be Faraday”), but seemed to develop increasing unease as the full extent of Faraday’s superior talent became apparent. Faraday’s contributions are so numerous that it is impossible to do more than focus on a few highlights, but together they record a breathtaking pace of discovery. This was a man on fire. His initial work was dedicated to advances in chemistry, given his mentor’s field of expertise. His work in electricity was then limited primarily to exploiting Voltaic piles to decompose substances, again in the manner of Davy.
The year 1821 was to prove an important turning point for Faraday. At 30, after rethinking his earlier dedication to a monastic existence, Faraday married a fellow Sandemanian, Sarah Barnard. His passions were evidently not limited to unlocking the secrets of nature, as the following letter to Sarah (written while pulling an all-nighter alone at the Institution’s lab in December of 1820) shows:
My Dear Sarah,
It it astonishing how much the state of the body influences the powers of the mind.
I have been thinking all the morning of the very delightful and interesting letter I would send you this evening, and now I am so tired, and yet have so much to do,
that my thoughts are quite giddy, and run round your image without any power of themselves to stop and admire it.
I want to say a thousand kind and, believe me, heartfelt things to you, but am not master of words fit for the purpose; and still, as I ponder and think on you, chlo-rides, trials, oil, Davy, steel, miscellanea, mercury, and fifty other professional fan-cies swim before and drive me further and further into the quandary of stupidness.
From your affectionate Michael
Allusions to chlorides, oil and mercury are rarely found in the romantic literature, but they did the trick, for he and Sarah were soon married; they would remain together until Faraday’s death in 1867 (she would pass away 13 years later). The year 1821 also marked his first historically important achievement in the electrical arts. Faraday had been trying to make sense of the same paper by Ørsted that had inspired Ampère. Especially intriguing — and perplexing — was the behavior of a compass moved around a current-carrying wire. To Faraday, the observations sug-gested the imagery of a sort of cyclonic wind encircling the wire. The “wind” pointed in the right direction to explain everything that Ørsted reported, including why the compass needle pointed at right angles to the wire — the needle behaved exactly as would a flag in a breeze. It explained why two parallel current-carrying wires could attract or repel: If the currents are in the same direction, the “cyclones” rotate in a direction that pulls them together. If one of the currents reverses, the cyclones push each other away. That dynamic picture of action in the invisible space between wires was to have far-reaching consequences, as we will eventually see in the chapter “Nothing is very important.” In the short term, it was to inspire Faraday to create the world’s first, though crude, electric motors. Here’s what he did:
FIGURE 22. Faraday’s motors (Experimental Researches in Electricity, vol, 2)
The figure shows two motors; we’ll focus on the one on the right. There, a cylindri-cal permanent magnet is fixed in place at the center of a cup filled with mercury, which you probably know is an electrically conductive liquid at room tempera-
ture.48 Touching that mercury is a wire suspended from a pivot, allowing the wire to move freely in a circle around the central magnet. Faraday reasoned that, if his “cyclone” picture was correct, this arrangement would allow the cyclone surround-ing the permanent magnet to push at an angle against the cyclone surrounding a current-carrying wire, and thereby produce rotary motion. When Faraday closed a switch, allowing a battery (not shown) to force current through the suspended wire, the wire dutifully and continuously traced a circle in the mercury, around the cen-tral magnet. Reversing the current reversed the rotation of the wire. For the first time in history, electricity was used to produce a constant motion. Practical motors were only a few years away.
48.It is also toxic. Faraday suffered later in life from chronic ailments that many authors have attributed to mercury poisoning. He paid a heavy price for his laboratory work.
Excellent scientist that he was, Faraday showed that a movable permanent magnet would also trace a circle about a fixed current-carrying wire, as required by the symmetry inherent in his cyclone picture. The corresponding configuration is shown in the unlabeled left-hand part of the figure above. He ran that experiment, and was again rewarded with confirmation of his deep physical insight. In one very full year, Faraday married, devised a powerful mental picture of how magnetism works, and used that picture to invent not just the world’s first motor, but the world’s first two electric motors.
This auspicious beginning promised still greater achievements, but Faraday would have to overcome some political difficulties first, for his invention of the motor turned Davy from an envious mentor to an active adversary. Davy had been work-ing with one William Hyde Wollaston to build a motor himself, and the duo had failed. Faraday’s paper acknowledged neither gentleman, and Davy chose to take great offense at the omission. In a fit of pique, Davy campaigned against Faraday’s election to membership in the prestigious Royal Society, charging plagiarism. Wol-laston came to Faraday’s aid, fortunately, and Faraday was made a Fellow of the Royal Society despite opposition from his powerful former mentor. Not wishing to risk even the remotest possibility of another distasteful episode, he stayed well away from any research area in which Davy was active until Davy died in 1829, at a young age 50 (likely from the cumulative effects of partaking too many of his
chemical creations).49 One can only speculate how many inventive contributions were lost because of Faraday’s self-censorship.
Once Davy was out of the picture, Faraday turned his full attention back to electro-magnetism. He wanted to complete Ørsted’s quest, and show that a magnetic effect could produce an electrical one.
He tried lots of things that didn’t work. Since electric current through a coil pro-duces magnetism, perhaps putting a magnet inside a coil would produce electricity. He tried it, but it never worked. Had it worked, it would have meant that one could produce unlimited amounts of energy for free, and Faraday intuited that somehow nature would disallow such a result.
49.His fondness for inhaling nitrous oxide (N2O) is well known, but he also tried a great many other substances, including nitric oxide (NO). Davy very nearly died when the highly unstable nitric oxide became nitric acid in the moist environment of his lungs.
Finally, two years after Davy’s passing, Faraday succeeded in his quest to show that magnetism could be used to produce electricity. He wound two coils of wire on a single ring of iron:
FIGURE 23. Faraday’s original “induction ring” (Royal Institution)
He energized one coil (called the primary winding) with an electrical current. He hoped that the magnetism produced by the primary would create (induce) an elec-trical effect in the second coil (called, sensibly enough, the secondary winding). He discovered that induction of a voltage would result if — and only if — the current in the primary were changing with time. The faster the primary current change, the greater the secondary voltage. Today we call this arrangement of two magnetically-coupled coils a transformer, and Faraday invented it.
Based on his ring experiments he reasoned that, since a varying primary current produces a varying magnetic strength, he ought to be able to induce a voltage in a coil by simply moving a permanent magnet into and out of it. He ran the experi-ment, and verified his prediction; he had just invented the first electric generator. Today that same, simple arrangement is the basis for the battery-less “shaker” flash-lights sold in hardware and novelty stores. There, a cylindrical magnet is free to move within a cylindrical coil. As the magnet moves back and forth, it pushes elec-trons along the wires of the coil, generating an electric current in the process. The power produced ultimately powers up a light. Whenever you shake such a light,
thank Faraday. Whenever you use electricity generated by the power company, thank Faraday. Whenever you drive a car, thank Faraday for the alternator (genera-tor) that keeps your battery charged.
Heck, just thank Faraday. So much of our modern life depends on his discoveries and insights in one way or another that it’s hard to find a piece of modern technol-ogy that isn’t enabled by a fundamental discovery of his.
FIGURE 24. Shaker flashlight
We’ll have a bit more to say about Faraday in a future chapter, but we’ll note here that Faraday’s powerful ability to visualize the invisible enabled him to develop an insight that ultimately was to enable wireless communication. He believed, but did not live to show, that light was an electromagnetic phenomenon. He fortunately did live long enough to convey his firm conviction to the man who would show it math-ematically, the brilliant Scottish mathematical physicist, James Clerk (pronounced “clark”) Maxwell. Maxwell’s achievement, in turn, would inspire a young German physicist, Heinrich Hertz, to construct the first wireless transmitter and receiver to prove that Maxwell was right. The discoveries of these scientists would give rise to a new profession — electrical engineering — whose practitioners would soon deliver the telegraph, telephone, electric generators and motors, the incandescent light, and wireless communication, all before the end of the nineteenth century. In short, the mayhem we associate with modernity was just around the corner.
Projects: Magnets, compasses, generators and motors
It’s surprisingly easy to make your own magnets, either by magnetizing objects made of iron to create a “permanent” magnet, or by following Ørsted in making an electromagnet. Once you’ve made a magnet, it’s pretty easy to make a compass. As it turns out, once you’ve made a compass, it’s not much of an additional leap to build a meter for measuring voltage or current. All of these objects and devices can be built using inexpensive, readily available materials, and without requiring any special skills.
Let’s start with making magnets out of iron or steel. If you happen to have a magnet already, you can use it to create more magnets. Take a sewing needle or iron nail, for example, and simply stroke it with the magnet. Don’t go back and forth, or you’ll undo what you’ve done. Just stroke it, lift the magnet, and stroke again. If the magnet is powerful enough, one stroke is sufficient. Remove the magnet and test the needle. You’ll find that it’s now magnetized.
Now what can you do if you don’t have a magnet to begin with? Take an iron nail, for instance, oriented parallel to the ground, along a north-south line, and give it a good thwack or three with a hammer. It will become magnetized! Why? The indi-vidual microscopic magnets within ordinary iron are only loosely locked in place. The mechanical violence unlocks them and sets them into motion. The earth aligns these microscopic magnets along the north-south direction while they’re jostling, so when the microscopic magnets settle back into place, they end up with a net magnetization.
Mechanical violence is not necessary, but its effectiveness explains why it is impor-tant not to subject magnets to mechanical shock, unless you want to demagnetize them.
Heat turns out to be as effective as mechanical violence, and for the same funda-mental reason. Heat drives random motion; the higher the temperature, the greater the motion. Above a critical temperature (which differs from material to material), heat destroys a magnet. If you bring the temperature back down below that thresh-old (known as the Curie temperature), the material can acquire a permanent magne-tization from external influences. So, if you simply heat, say, a steel sewing needle with a match, it will be found to magnetize upon cooling (if the needle is kept ori-
ented more or less along a north-south line during the process).50 If you ever need
Projects: Magnets, compasses, generators and motors
to build a compass (think Gilligan’s Island), keep the fire+needle recipe in mind. It’s also a great campfire activity for kids.
This heat sensitivity also explains how scientists know that the earth’s magnetic field has changed over geologic time. Volcanic flows contain iron. As the lava cools, the iron acquires magnetism aligned to the earth’s magnetic field at that loca-tion in space and time. In essence, the cooled lava constitutes a “tape recording” of the earth’s magnetic field over the period of time during which the volcanic activity persists.
This heat sensitivity has also been used in high-speed duplication of magnetic tape recordings. A master specially recorded on a high-Curie temperature material is brought in contact with the blank. The temperature is raised above the Curie tem-perature of the blank (but kept below that of the master), and the master and blank are sped along each other at a much faster rate than ordinary tape-to-tape transfers would allow.
Once you have a magnetized needle, making a compass is trivial. Stab the needle through a cork (or affix it to the top surface of the cork) or styrofoam packing “pea-nut,” and float the assembly in a pan or bowl of water, set on a stable surface. Shield it from wind, and watch as the cork or peanut rotates. When it stops, the nee-dle will be pointing along the magnetic north-south line. This information alone is insufficient to determine north from south, but at least it reduces the number of choices to two. Additional information (e.g., from the sun’s motion — remember, it sets in the west) allows you to figure out which end is which. A little drop of paint
or wax or some other thing to mark North51 completes your compass. This simple compass works surprisingly well.
50.This requirement would seem to suggest that you need to know which way north is, before you’ve made the compass. It’s really not that bad, though; you don’t have to have anywhere near perfect alignment. As long as you’re not oriented too closely to east-west, it will generally work. If the amount of magnetization seems unsatisfactory, simply change the orientation of the needle a bit, and try again. Repeat as necessary. You can always reduce the number of blind experiments if you have even a rough idea of north-south or east-west lines, say, by observing the sun in the daytime, or locating Polaris — the Pole Star — at night.
51.It is a confusing quirk that the end of the compass needle that points to the earth’s mag-netic north pole is actually of the same magnetic polarity as the earth’s south pole, because opposite poles attract.
Because a compass is sensitive to magnetic fields, it will also be sensitive to artifi-cially created magnetic fields, such as those produced by the electromagnet. If you wind a coil of wire about the compass, you can enjoy a much higher sensitivity than Ørsted achieved. Commercial electromagnetic voltmeters may use coils with hun-dreds of turns of extremely fine wire.
FIGURE 25. Compass as heart of ammeter52 or voltmeter
Ampère himself discovered the miraculous effect of using multiple turns. The cur-rent produces magnetism in each wire, so the use of many wires is an ingenious way to produce an augmented effect; the magnetism produced by one loop of wire adds to that produced by all of the other loops of wire.
When you exploit this effect to make a meter, it means that you can produce a more sensitive meter. That is, for a given current through the coil, the compass needle will deflect a greater amount.
Homemade generator
It’s not hard to recreate a demonstration of Faraday’s moving-magnet generator. You can use a coil wound around a compass as an indicator (a voltmeter), and another coil with a moving magnet as the generator, just as in a shaker flashlight.
52.Although, strictly speaking, one could argue that the proper term should be “ampmeter,” the word is awkward to say. The offending “p” was eliminated to give us “ammeter.”
Projects: Magnets, compasses, generators and motors
FIGURE 26. How to push electrons around, and then prove it
As you move the magnet in and out of the coil, you’ll notice that the compass nee-dle deflects one way, and then the other. You’ll also notice that if you stop moving the magnet, the compass needle will return to its original position: motion is neces-sary to generate a voltage. The magnet pushes around the electrons, but you are needed to push around the magnet. So indirectly, but in a real sense, you are push-ing the electrons. This connection is so strong that, as you draw more energy from the magnet-coil system (say, by trying to light up an ever-increasing number of light bulbs), the magnet gets progressively harder to move! It feels increasingly as if you are trying to move the magnet through molasses, even though there’s “noth-ing” between the magnet and the coil. You are invisibly but intimately coupled to the electrons through Faraday’s unseen magnetic cyclone.
Homemade batteries from pocket change
If you tire of pushing magnets around to generate a wee bit of voltage, you might want to recreate Volta’s pile instead. Batteries are now so commonplace that we for-get that a miracle of chemistry quietly goes on inside each one of them. Once we understand a bit about how a battery works, we’ll also have learned why certain metals corrode (and others don’t), what special things must be done to ships to keep them from disintegrating, and even how to electroplate one type of metal onto the surface of another.
In this part of the Appendix, we’ll learn how to make batteries out of ordinary household materials, such as pocket change.
As we’ve seen, Volta discovered that the key ingredients are two dissimilar metals immersed in an electrically conductive electrolyte.
The electrolyte plays an important role in battery functioning. When a metal is immersed in an electrolyte, some of that metal inevitably dissolves in it, releasing metal ions into the solution. This process proceeds until the unmated electrons left behind exert a sufficiently strong pull to balance the tendency for the metal to dis-solve in the electrolyte.
An important idea is that not all substances attract or hold onto charged particles with equal strength. When we immerse two different metals into an electrolyte, then, one metal generally ends up with a greater surplus of electrons than the other, creating a voltage between the electrodes. When we connect a consumer of electri-cal power to the battery (engineers call this device a load), current flows. Electrons travel from where they are overabundant, through the load, and eventually to where they are relatively scarce. The electrode that supplies the electrons then exerts less electrical force on its own atoms, and more electrode atoms dissolve into solution. This dissolution explains why batteries eventually run down — using the battery to power things causes the parts to dissolve.
The voltage produced by a battery depends on the materials used. The more dissim-ilar the electrodes, electrically speaking, the higher the voltage. The amount of cur-rent that can be supplied by a battery is proportional to the total electrode surface area, as well as the strength of the electrolyte (the faster it can dissolve the metal, the greater the quantity of electrons liberated per unit time). Putting batteries in series increases the available voltage without affecting the available current, while putting them in parallel increases the available current without altering the avail-able voltage.
Now, commercial batteries often use hazardous chemicals, such as the sulfuric acid (H2SO4) used in lead-acid car batteries, or the potassium hydroxide (KOH) found in alkaline batteries. We don’t want to fool around with these sorts of dangerous substances in home projects. In fact, we don’t even want to play with the relatively benign ammonium chloride (NH4Cl, known in days of yore as sal ammoniac) used in the cheapest “carbon-zinc” flashlight batteries. So we’re going to seek alterna-tives that get the job done without exposing us to much risk. The tradeoff is that the batteries we make at home will not be as powerful or convenient as store-bought ones. But it sure is satisfying to be able to use junk bits to make something useful
Projects: Magnets, compasses, generators and motors
The penny battery
Perhaps the simplest and cheapest recipe uses a penny as one electrode, a piece of felt or paper towel soaked in some electrolyte, and a piece of aluminum foil as the other electrode, all arranged in a repeating stack as follows:
FIGURE 27. The penny battery, and how to prove that it works
The piece of paper towel is soaked in the electrolyte, and has to be large enough to make sure that the penny and aluminum foil within a cell do not touch each other (this would create a short circuit). It is all right — in fact, necessary — for the alu-minum foil of one cell to make excellent contact to the penny of the next cell. Indeed, it is advisable to smooth out the foil to improve the contact area. A clean penny helps, too.
When ketchup or vinegar is used as the electrolyte, you can generally expect about a half a volt from each individual cell. Such a cell can’t supply very much current, though (typically less than 1/1000 of an ampere — 1milliampere). In fact, it is far too feeble to light a flashlight bulb. However, several of these in series will readily operate a wristwatch or small calculator, or even a small light-emitting diode (LED) to a dimly perceptible glow.
Some simple modifications to an ordinary calculator allow it to be powered up by the homemade battery, as shown in the figure above. Simply open up the calculator and remove its factory-supplied battery. Connect a wire to the terminal that nor-
Felt + CokeAluminum foil
Penny
Felt + CokeAluminum foil
Penny
Felt + CokeAluminum foil
Penny
(+)
(-)
Cell (repeatfor morevoltage, ifneeded, but
(Can use paper towels instead of felt; they just disintegrate easily)
mally connects to the positive battery electrode, and connect another to the negative terminal. Engineers generally use red wire for positive voltages, and black for neg-ative, so that’s what indicated in the figure. You don’t have to follow this conven-tion, but you definitely need to do something to keep the polarities straight.
As shown in the figure, the copper electrode is the positive terminal of the battery. The reason is that copper holds onto electrons less tenaciously than does aluminum.
If your battery works, and if you’ve made no wiring errors, the calculator should spring to life. Press “clear” and then try a calculation. Try extracting the square-root of “888888888” (this value “lights up” all of the segments that make up the display, and thus maximizes current drain for a rigorous test). If your batteries last long enough to complete the calculation, pat yourself on the back!
You should experiment with this general arrangement of Volta’s pile. Try different electrode materials, say, dimes instead of aluminum foil, for instance. Or nickels (they’re cheaper). Try different electrolytes. Various juices work well. So do many soft drinks, such as Coke or Pepsi. Salt water does, too, and it’s certainly easy to make. Vinegar and even potato juice work. Bananas do, too, as it turns out. Just resist the temptation to eat these things after you’ve done battery experiments with them.
Powering up a calculator with junk is miraculous and fun. Perhaps that success only whets your appetite. If you want to get more oomph out of the battery, we need more surface area. You could use many batteries in parallel or series, but that’s unwieldy and a lot of work to connect up. An alternative is to use a copper scouring pad in place of the penny (e.g., “Chore Boy” brand pads). The copper segments accessible through all those nooks and crannies add up to a considerable amount of exposed metal surface area. Connect a wire to the pad, then surround the pad com-pletely with a paper towel (two or more layers is a good idea, just to make sure that the wet towel doesn’t tear anywhere and inadvertently short out the battery). Next wrap aluminum foil around the paper towel. Crinkling the foil ahead of time helps to increase the useful surface area, but you’ll inevitably crinkle it during construc-tion, so you don’t have to do much extra work.
You may use the same electrolytes used earlier with the pennies. For better perfor-mance, however, it is a good idea to use something stronger. Both acids and bases
are good candidates in general, but bases are probably better in our case.53 The rea-
Projects: Magnets, compasses, generators and motors
son is that aluminum has such a strong affinity for oxygen that it is invariably found bound to it. There is always a microscopically thin layer of aluminum oxide on any aluminum surface. This oxide, unlike ordinary iron rust, is transparent. Further-more, it inhibits further oxidation because oxygen is too big to squeeze through the aluminum oxide (regrettably, iron oxide is very permeable to oxygen, which explains why rust just keeps growing). The relative impermeability of aluminum oxide is why aluminum foil stays shiny under most conditions; it creates its own protective skin.
While the oxide layer is good for inhibiting corrosion, it also impedes the flow of current, reducing the useful output of the battery. Alkaline (basic) electrolytes help to inhibit formation of aluminum oxide, and thereby generally increase the output of such a battery.
A particularly good basic electrolyte is a solution of sodium hydroxide (NaOH, commonly known as lye or caustic soda). Unfortunately, it is poisonous if ingested, and eagerly attacks flesh (in fact, lye is used to convert fat into soap, and it will happily convert the fatty tissues of you into soap; this action is generally deemed “suboptimal”), so I cannot recommend using it. If you ignore this advice and pro-ceed to use lye anyway, wear eye protection and gloves. And please use dilute solutions. A drain opener such as Drano or Red Devil is a suitable source of lye (Red Devil is nominally pure lye, while Drano has some aluminum mixed in). Dis-
solving a teaspoon of lye in one cup of water produces a reasonable electrolyte.54 Again: Avoid contact with flesh, protect your eyes, don’t get any in your mouth, and exercise caution!
With a copper scrubpad-aluminum foil electrode combination immersed in a sodium hydroxide electrolyte, one may expect an open-circuit voltage of about 1.7V (just a little bit greater than an ordinary flashlight battery), and a short-circuit current in excess of 0.2 amperes! Such a battery will light a small flashlight bulb or LED, and readily operate a small toy motor. Two in series will brightly light a bulb, and spin a toy motor impressively fast.
53.Acids tend to taste sour, while bases generally taste bitter. However, it is a decidedly bad idea to go about tasting random chemicals. This was once the tradition among German chemists in the late 1800s and early 1900s, until so many deaths occurred that this bad habit was stopped.
54.For those of you with a chemistry background, the aim is to produce an electrolyte of approximately 1M concentration. The exact value is not critical; a factor of two either way will make little difference.
A safer choice for home experimentation is washing soda (sodium carbonate, Na2CO3). This common laundry detergent “booster” can be purchased at many gro-cery stores if you don’t already happen to have it handy (it is very inexpensive). Or, if you are determined to make this project more challenging, you can make your own, by converting baking soda (sodium bicarbonate, NaHCO3) into washing soda by heating it up (the fancy term for the process is pyrolytic decomposition). In this process, heating causes sodium bicarbonate to release both water and carbon diox-ide:
. (1)
The water and carbon dioxide evaporate away during the process, leaving behind just the desired sodium carbonate. (As a side note, baking soda works its magic in cooking precisely because of these gases given off during baking. They help make dough rise, filling it with numerous minute holes and channels as the gases escape.) What follows are specific instructions for making your own washing soda from baking soda:
1) Place a half cup of baking soda in a suitable oven-safe (e.g., Pyrex) container. The shape is not too critical, but a larger surface area is desirable, so if you have a choice between a baking dish and a measuring cup, the dish is preferable.
2) Heat in an oven at, say, about 350°F for one hour, or for 10-15 minutes after the powder has stopped bubbling noticeably.
3) Remove the container and let it cool to room temperature.
Make a solution of the washing soda and use it as the electrolyte in your scouring pad battery. Any leftover washing soda can be used the next time you do your laun-dry (most modern detergents contain washing soda), or the next time you decide to fool around again with homemade batteries. Nothing goes to waste in Things About Stuff experiments!
There are infinitely many ways of making a motor, some good and most not so; we’ll settle for the latter. This last of the three challenges constrains what you can do by limiting the available materials to a ludicrously meager set: A “D” size bat-tery, a couple of feet of wire, and a magnet that has been salvaged from a disk drive.
Projects: Magnets, compasses, generators and motors
Simple motor
Just in case you haven’t spent your entire life studying the design of motors from surplus materials, here’s a time-tested version you may consider as a starting point for your improvisations:
The coil wire is enamel-coated copper, so you need to remove some of the insulat-ing enamel from the horizontal stubs to make electrical contact to the battery. In lieu of making a classical “commutator”” (needed to reverse polarity so that the coil doesn’t have two equilibrium positions), remove only the enamel along the upper surface of the two horizontal stubs. That way, the coil will only be energized during half the rotation, giving it at least the chance of spinning continuously. You will need to get things going by giving it a spin, after which inertia should keep the motor operating on its own (if all goes well).
The (separate) wires leading to the battery also serve as mechanical supports and electrical contacts to the horizontal stubs. A standard choice is to use paper clips for these elements. Figuring out exactly how to put it all together is part of the chal-lenge.
Magnet
+ -
Coil (n turns)
remove only upperenamel coating (seetext)
Paper clips, e.g.(mounting methodon base not shown)
President James Madison announced that the beloved Marquis de Lafayette — French hero of the American Revolution and friend to George Washington — would mark the 50th anniversary of the Revolution by visiting all 24 states as “the nation’s guest.” New York City’s Common Council (forerunner of today’s City Council) in turn would honor his grand tour by commissioning a portrait of Lafay-ette. After considering and rejecting a number of prominent candidates, the Council ultimately selected a rising young talent, 33-year old Samuel Finley Breese Morse.
News of winning the commission — and the funds it promised — arrived just in time. Samuel’s wife, Lucretia, was carrying their third child, and the young cou-ple’s debts had become oppressive. The job, though, required Morse to travel to Washington, D.C. for the sitting. Any unease he might have felt at leaving Lucretia behind in New Haven was moderated by the knowledge that his own parents would be looking after her. Besides, she was a healthy 25-year old who had already borne two children without any complications. He set out for Washington in November of 1824 with a light heart.
Lucretia gave birth to their third child, James, on schedule in early January as Morse was finishing the painting. All was well with James but Lucretia soon fell ill. When her condition worsened Morse’s father sent word and, after the usual two-week mail delay (horses, remember), Samuel received the troubling news. He arranged for a hasty return but, sadly, Morse was unable to return quickly enough (horses again). Lucretia died one month after giving birth and was already buried by the time Morse arrived. The communication delay had robbed him of a chance to say goodbye to his wife. It is not too great a leap to suggest that the bitter mem-ory of that theft would subconsciously drive him to annihilate the twin foes of space and time.
From artist to inventor
Although Morse was born in the same year as Faraday, the two gentlemen initially had little else in common. Morse certainly did not set out to be a scientist or inven-tor. Nothing in his choice of classes in college hinted at much of an interest in, let alone a passion for, the sciences. At Yale he studied the usual variety of subjects, including some chemistry and mathematics. Religion interested him much more, but art was his true passion. Indeed, he was able to underwrite much of his educa-tion by painting and this success convinced him that art could be both vocation and
avocation. He decided to commit to a life in art and within a year of graduating in 1810, Morse made his way to England’s Royal Academy to further his studies. Not long after settling in, Morse sculpted what most critics consider his masterpiece, The Dying Hercules.
FIGURE 30. Morse (c. 1845) and his masterpiece of 1812
The War of 1812 was then raging and the sculpture was — and is — widely inter-preted as a negative commentary on British imperialism. He evidently did not wear out his welcome with works like these, though, as Morse remained in England until the autumn of 1815. He spent the decade after his return to America working dili-gently to establish himself as an important artist. In an early triumph, he won the job of painting a portrait of former president John Adams in 1816. He also met 16-year-old Lucretia Pickering Walter that year, while in New Hampshire to drum up some business. The two were engaged not long afterwards, and married by 1818.
FIGURE 31. Lucretia with Susan and Charles (portrait by Morse, of course)
Morse’s fame grew steadily along with his family. The couple were blessed with two children (Susan and Charles) by 1823 and, except for intermittent money trou-bles, the Morses were the picture of happiness until Lucretia’s death in 1825. The loss of Morse’s father the following year, and then the death of his mother less than two years after that left Morse reeling. Placing his children in the care of other fam-ily members, Morse headed to Europe to take a sabbatical from grief. He visited Lafayette and the writer James Fenimore Cooper in Paris, toured the Continent and studied as many art collections as he could locate. The healing balms of friendship, art, distance and time worked magic and by 1832 he was ready to return to Amer-ica.
He befriended a Dr. Charles Jackson during the six-week-long voyage back to New York aboard the Sully. Jackson was a bit of a nerd who knew a fair amount about what was going on in the exciting world of electromagnetics, including primitive efforts in Europe to build telegraphs. Morse was happy to learn about these new developments and Jackson was probably delighted to meet someone who didn’t find him lethally dull. Indeed once Jackson suggested that this sort of research could make instantaneous communication a practical reality someday, Morse shifted from genial travel companion to nascent inventor with astonishing rapidity. He was driven by a passion whose origins he may not have consciously acknowl-edged. He was so taken by the idea, in fact, that by the end of the voyage Morse had recorded rough ideas for his own telegraph in his sketchbook. Contemporary efforts
at telegraphy, he learned from Jackson, involved complex schemes, such as com-pass-like needles that spun to point at letters arrayed in a circle. His relative igno-rance led him toward a simpler and eminently more practical approach.
As intriguing as these ideas may have seemed during the voyage, Morse didn’t immediately develop them further upon arriving home. For one thing, his schooling in the electrical arts was largely limited to what he’d gleaned from Jackson, supple-menting the little he could recall from a few lectures he’d attended in his college days. He was aware that he lacked the expertise to evaluate whether what he had conceived would actually work and, indeed, even to evaluate how much more he would need to know. He’d have to do quite a bit of homework before he could go much further and he had more urgent priorities to address first. He needed to rebuild his professional standing after the long absence and, most important, he had to reacquaint himself with the children he’d virtually abandoned.
By 1835 — a decade after Lucretia’s death — Morse felt ready to return to the tele-graph in earnest. He began building bits and pieces of apparatus and demonstrated some of them to his friends and acquaintances. These early experiments exposed the near-infinite breadth and depth of his ignorance. He knew nothing about wire (how thick should it be? how far can one transmit electrical effects?); about batter-ies (how much “tension”? how much current?); and about electromagnets (how many turns of wire? how large an iron core? what shape?). His problems were legion, so in early 1836 he sought the help of NYU science professor Leonard Gale. Within a year the two had become business partners and were joined soon after by an acquaintance of Morse named Alfred Vail, whose father had attended one of Morse’s early demonstrations. Vail was a man of means as well as a talented machinist and his addition to the team enormously accelerated their progress. As word spread of Morse and Gale’s grand plans, Morse’s erstwhile travel companion, Dr. Jackson, popped up to claim ownership of these ideas. This legal difficulty was just the beginning of troubles to come.
Despite Jackson’s claims, Morse proceeded to file a telegraph patent application in 1837, two years before the British engineers Sir William Cooke and Charles Wheatstone would put their own needle telegraph into operation on a 13-mile stretch of the Great Western Railway (itself an engineering triumph, designed by the great Isambard Kingdom Brunel, whom we’ll meet in the following chapter). Within a year of that filing, Morse and Vail completed their work on the dot-and-dash code, using the binary signaling now to represent individual letters, rather than whole words, as in Morse’s original concept. Vail had suggested assigning the shortest symbols to the most frequently-occurring letters (this concept would be formalized nearly a century later, where it would be known as Huffman coding and
used for data compression). This way, the average time to transmit a typical piece of text would be kept to a minimum, enabling more transmissions — and thus more revenue — per unit time. He cleverly estimated the relative frequency of letters by simply examining the collection of movable type in the print shop of a local news-paper. The letter e was by far the most common and so he chose a single dot to rep-resent it. A single dash represented the next most common letter, t. Continuing through all the letters of the alphabet in this manner produced a set of symbols that eventually evolved into what you know as Morse code (even though Vail probably did the bulk of its inventing). Although the Morse code we use today differs in detail from that first version, Vail and Morse had essentially completed by 1838 the use of simple on-off states to represent the entire alphabet and numbers in a practi-cal way.
With these developments in place Morse finally felt ready to demonstrate his com-plete system. He and his partners succeeded in getting a contingent of congressmen to agree to one such demonstration in early 1838. In attendance was Maine repre-sentative Francis Ormond Jonathon Smith, who was so impressed that he privately demanded — and received — part ownership in the venture. He concealed this business relationship from the public and his fellow congressmen while advocating for federal monies to construct a prototype 50-mile telegraph link to demonstrate practicality. Smith failed repeatedly and served out his term in office without hav-ing enjoyed any advantage from this flagrant conflict of interest. Indeed it took five years of maneuvering before Congress finally agreed to a $30,000 appropriation for the project, which was to link Washington, D.C. with Baltimore. Initial plans called for the use of underground cables, to be installed using machines specially designed by an acquaintance of Congressman Smith named Ezra Cornell. Unfortunately underground installation proved impractically expensive and slow. That, plus con-cerns about reliability and maintenance expense killed off that idea. Cornell’s “plan B” — mounting overhead wires atop wooden poles — became the standard method of wiring up networks for the next century.
By 1844 the system was ready for the historic test. On May 24 the first official mes-sage, “What hath God wrought?” was sent from the Capitol’s Supreme Court cham-ber to the B&O Railroad depot in Baltimore. This message was not the first sent on the system (many test messages preceded the ceremonial event, of course), but it’s the one cited in most histories of the telegraph. Not only was the message not the first sent on that telegraph link, it was not even sent on the first telegraph link. As Jackson had taught Morse, competing telegraphs — albeit crude, impractical ones — had been in operation in Europe for some years before the Washington-Balti-more test. Although these other telegraphs lacked the practical advantages of the
Morse system, it would take time for the courts to resolve the question of inventor-ship.
The Morse system was simplicity itself, consisting of a battery, a switch (the tele-graph key) and an electromagnetically deflected pencil that wrote on a moving strip of paper. When an operator pressed the telegraph key, the switch closure connected a battery to an electromagnet. The electromagnet moved the pencil one way for a dot and the other for a dash, leaving a distinct written pattern on the paper tape as a permanent record, allowing messages to be received continuously without a human present. Morse, artist that he was, had used parts from a picture frame to construct his first prototype (that historic artifact is on display at the Smithsonian Institute in Washington, D.C.). His paper tape idea would exhibit remarkable longevity, surviv-ing into the 1980s as a storage medium (with punched holes instead of squiggles written in pencil) for early personal computers.
As the telegraphic art progressed Morse and his associates noticed that experienced telegraph operators were transcribing Morse code by listening to the characteristic clicks made by the pencil-deflecting apparatus, instead of following the “proper” procedure of working off of the paper tape record. Operators had found that they could decode much faster this way, so changes were made to exploit this chance discovery. To enhance the sound, an electromagnetically-operated metal striker quickly emerged as the preferred arrangement and, in many installations, the slow and often-unreliable paper tape mechanism was abandoned altogether in favor of the sounder alone.
Morse and his colleagues had constructed a telegraph capable of successfully span-ning the 40- to 50-mile distance. The nearly instantaneous “speed of electricity” contrasted with the several hours it took to deliver a message over that distance even with the fastest horses. The telegraph that Morse had wrought would have allowed him to hold Lucretia’s hand one last time.
Telegraph networks sprouted like kudzu over the next ten or so years. Morse remar-ried (to Sarah Elizabeth Griswold, a second cousin), fathered four more children and finally won all of his patent battles in a Supreme Court decision delivered in 1854. He used the Court’s decision as the proverbial “big stick” to amass a fortune. Ezra Cornell purchased a telegraph company that had been forced into bankruptcy and ultimately drove the formation of Western Union, which by the end of the Civil War would become the world’s first telecommunications monopoly. With the wealth that monopoly brings Cornell went on to co-found the university that bears his name.
Having fulfilled his telegraphic dreams, Morse occupied the rest of his life with more relaxing endeavors, including supporting George McClellan against incum-bent President Lincoln, publishing strident screeds opposing the Emancipation Proclamation on biblical grounds, and trying to convince the U.S. government that Catholics in general (and the Pope in particular) presented an imminent military threat. His warnings were foolishly ignored, which is why we now eke out a desper-ate, hardscrabble existence under the oppressive thumb of a totalitarian Papist regime.
Morse was not like the other kids.
He clearly had some loose bits rattling around in his cranium, but none of that takes away what he achieved. His vision and persistence, born of tragedy, did give us the telegraph. The world would continue to shrink, thanks to that first triumphant anni-hilation of space and time.
Telegraphy under the hood: Project ideas
Ampère showed that winding wire into a multi-turn coil intensifies the magnetism produced by a current (see Chapter 2’s projects). This magnification occurs because the magnetic force exerted by one loop of wire adds to that exerted by all of the other loops. In 1825, only a couple of years after Ampère’s first publications on the subject, an English scientist, William Sturgeon, extended Ampère’s work and con-structed the first electromagnet strong enough to lift its own weight. He had discov-ered that winding a coil around a bar of iron greatly intensifies a magnet’s strength. Today we understand that the magnetism generated by subatomic processes within the iron adds to that generated by current in the coil. Not long after Sturgeon’s work, Yale’s Joseph Henry — who would later serve as first Secretary of the Smith-sonian Institution — demonstrated in 1827 that Sturgeon’s achievement by no means represented a limit. By winding coils with multiple layers of multiple turns of insulated wire on an iron core, Henry constructed giant magnets that were capa-ble of lifting many times their own weight. His largest, completed in 1832, was able to lift approximately 3600 pounds. He could’ve gone further, but he’d made his point. Descendants of Henry’s mighty magnets routinely perform yeoman duty in junkyards around the world:
An advantage of an electromagnet is its ability to turn on and off, as Morse appreci-ated. Close a switch to enable current to flow, and the electromagnet is ready to lift a junk car. Position the junk where you want it, open the switch, and gravity does the rest. Rinse and repeat.
The simple on-off nature also means that it is easy to build a telegraph. The con-cepts and materials are readily accessible, and constructing one is well within the capability of elementary-school students. The only moderately tricky part (and it’s still not that difficult) is finding or building a sounder (the part that clicks), so we’ll offer a somewhat nonstandard choice that makes use of ubiquitous obsolete com-puter gear. You are encouraged to explore your own variations based on the themes we present. That is, take our project ideas as a starting point, as opposed to treating them as a rigid set of instructions to be followed slavishly. Improvise with materials at hand if you don’t happen to have exactly what’s described here.
For both versions of our homebrew telegraph, you will need one healthy flashlight battery (a D-size cell will last a good long time, but other sizes are fine, too), and perhaps a battery holder (available from electronics stores, such as Radio Shack), although adhesive tape or rubber bands can be used for temporary — if tenuous — connections. Regrettably, the penny-and-aluminum foil cells don’t have enough
juice to get the job done (unless you make and connect a lot of cells). However, the scrubpad battery will work, so if you’re absolutely determined to build everything yourself, that’s a suitable cell.
Next you need a switch of some kind:
FIGURE 33. Type used aboard the Titanic (left); and inexpensive modern key
The minimalist key on the right shows how little is required: A springy piece of moving metal makes contact to a stationary piece of metal; it’s just a switch. A cou-ple of binding posts allow us to make electrical connections to the key. What sepa-rates such a simple key from more professional ones, such as those used aboard the Titanic (as in the photo above, left), are subtle but important qualities. The springi-ness of the return, the balance and mass of the moving arm, the feel of the key, the gap between contacting surfaces, and the quality of the electrical contact all matter greatly to the professional telegrapher, just as the particulars of a piano’s action matter to a professional musician. For a quick home project, however, simplicity is perhaps the most important consideration. If you’d rather buy than build, keys sim-ilar to that shown on the right are commercially available for only a couple of dol-lars.
If you’re adventurous enough to build one, you can easily construct a functional telegraph key out of a scrap piece of wood, thick wire, and a couple of screws and washers. A typical metal coat-hanger is a terrific source of suitable wire — it’s the right thickness and of the right composition to have a useful natural springiness. Carefully cut a piece (a wire-cutter isn’t strictly needed, but yields better results than, say, repeated bending to break the coat-hanger wire) about 3”-4” (8-10cm) or so. Use sandpaper to abrade away any surface varnish or paint, or otherwise remove any insulation — it’s essential that you get down to bare metal wherever you expect
electrical contact. Then, simply screw one end down onto the wood base using a pair of washers, as shown below. Another screw and washer form the other contact, and you have a telegraph key. Rudimentary, yes, but it will get the job done.
FIGURE 34. Crude — but serviceable — homebrew telegraph key
Next, we need a sounder. As it happens, a simple one can be salvaged from a cast-off computer. The small speaker used for warning beeps and such is a perfectly fine sounder, and should be among the several items a good nerd rescues from an old computer before recycling the rest. Although it isn’t immediately obvious from looks alone, a speaker works on pretty much the same principles as a classic tele-graph sounder; they both depend on electromagnets pushing or pulling on some-thing else:
FIGURE 35. Telegraph sounder (invented by Vail, c. 1850)
In the sounder originally invented by Vail, an electromagnet pulls a pivoted striker bar downward when energized, making a nice, loud click as the striker hits its lower limit of travel. A spring pulls the bar back upward when current through the elec-tromagnet ceases.
A speaker differs only a bit. It has a diaphragm affixed to a freely movable coil of wire wound around a cylindrical form. Current flowing through the coil generates a force against a cylindrical permanent magnet that it surrounds and which is not free to move. The movement of the diaphragm creates sound by pushing air around, rather than by hitting a solid stop. Unlike a telegraph sounder, then, a speaker can reproduce more than just on and off, but that doesn’t preclude its use as an on-off operated noisemaker:
FIGURE 36. Retro-modern mashup: Telegraph using PC speaker
Although the figure shows a disembodied speaker in free air, putting the speaker in some sort of an enclosure will help produce a much louder sound (that’s why stereo speakers are in boxes). Almost any box would be better than none. A cigar box or something like it would be a great starting point. Carefully cut out a circular hole just a bit smaller than the speaker, and then mount the speaker in the box. If you compare loudness with and without the box, you’ll be impressed by how big a dif-ference a box can make.
Box or no, each depression of the key causes the speaker to emit a clicking sound. Build a matching set for a friend, use long wires, and you’ve taken your first steps along the same trail that Morse blazed over 160 years ago.
The value of instant communication was obvious to everyone and telegraph net-works expanded rapidly. By the start of the U.S. Civil War, much of the continental U.S. was connected and it was easy to envision a day — soon — when essentially the entire country would be linked by telegraph, thanks to the progressive annihila-tion of space and time.
Visionaries started to imagine how much smaller still the world would be if we could connect all the continents together in a vast global network of telegraphs. Sensible scientists didn’t spend much time on such fanciful, impractical musings, but progress often depends on a certain amount of studied ignorance, if not outright foolishness. Money helps, too. A lot. That is, a lot of money helps to enable a lot of foolishness.
In that context the name Cyrus West Field should be much better known than it is. I’m sure right now you are thinking, “Cyrus who?” He was the possibly foolish, certainly visionary and definitely wealthy man who, by sheer force of will, almost singlehandedly drove the Victorian equivalent of the Moon program: Laying a tele-graph cable across the Atlantic.
Field, like Morse, was not a scientist. He wasn’t an inventor, either, and never aspired to be one. He was a businessman and, in the 1840s, he had the misfortune of working for E. Root and Company, a New York paper wholesaler that was incom-petently (and perhaps dishonestly) run. When the firm finally failed, the directors gave Field a “battlefield promotion,” which mainly meant that, as new head of the now-dead company, he was assigned the unpleasant task of informing creditors that they weren’t going to get paid. After considering numerous alternatives, Field found himself asking the directors for permission to resurrect the company. They acceded and he succeeded — brilliantly. The revived firm became hugely profitable in a short time. He repaid all of the original creditors, with interest, even though he was under no legal obligation to do so. Such noble ethics, plus his ability to turn the company around in the first place, made his reputation as a brilliant, honest busi-nessman. Having earned a fortune for himself and others, he retired in 1852 at the age of 33.
Driven personalities rarely tolerate retirement well and Field was no exception. He probably drove his wife and kids crazy with constant suggestions for improvement here and there. One can imagine Mrs. Field gently suggesting to her Type-A hus-band that he find a new hobby, preferably something involving extended long-dis-tance travel.
FIGURE 37. Cyrus Field, with the entire earth within reach
As one of the wealthiest men in New York, Field was always being approached by someone with “a really great business idea.” Sometimes he’d listen politely with feigned interest but most of the time, he’d send these folks on their way. One day in 1853 an earnest caller, Frederick Newton Gisborne, arrived on his doorstep with a letter of introduction from Field’s brother. The gentleman — a telegraph geek — breathlessly pointed out to Field that extending the telegraph out to Newfoundland from its present New York terminus would cut the one-way communication time to England by two whole days. So, instead of taking 14 days, a message could be sent in 12 days. The government of Nova Scotia had already funded Gisborne’s project in 1851 but the effort had collapsed in bankruptcy amid charges of incompetence and fraud. Gisborne hoped that Field would find the business case compelling and give him the funds needed to complete the project and rescue his reputation.
Field thought about this for about a nanosecond and then told the poor guy that a savings of two days was too trivial an improvement to make an investment worth-while. He thanked Gisborne, then sent him packing.
As Field thought about it some more, he considered again that the problem with Gisborne’s plan was its lack of ambition. Looking at a globe, Field saw that it was just “a little bit further” to go from Newfoundland to Ireland. Rather than cutting communication time from 14 to 12 days, such a “modest” extension would cut it down to zero. That, he knew, would be worthwhile. It would connect two conti-nents for the first time in history and in so doing it would couple America and Europe together in ways that would certainly lead to great wealth, world peace, slimmer thighs and rosier complexions. All he had to do was build it.
First he had to establish whether the ocean floor would allow the practical laying of a cable at all. He was surprised and delighted to discover that Lt. Matthew Maury (later to be known as the father of oceanography, as well as the founder of the U.S. Naval Academy) of the U.S. Navy had just completed the first-ever depth survey of the Atlantic, along the very route of interest to Field. In 1856, Maury summarized his findings in a letter to Field:
From Newfoundland to Ireland …(there) is a plateau, which seems to have been placed there especially for the purpose of holding the wires of a submarine tele-graph, and of keeping them out of harm’s way.
As Field examined the actual depth profile (see Figure above), he was amazed at the complete absence of dangerous features anywhere along the proposed route, just as Maury had said. There were no deep trenches, no scary undersea mountain peaks, just a relatively flat underwater road between St. John’s, Newfoundland and Ireland’s Valentia Bay. Field must have felt an electric thrill upon reading Maury’s letter. Providence had provided.
Field’s fortune, though substantial, was not nearly great enough for a venture of this magnitude. He assembled a group of investors from his circle of wealthy friends and started planning the project. He talked the British into underwriting part of the venture and supplying a ship for cable-laying. He persuaded the U.S. Congress to appropriate funds as well; the bill passed by a single vote (anti-British sentiment still ran high, even forty years after the War of 1812). Since none of the investors knew anything about electricity, let alone its use in telegraphy, Field sought out experts, including Morse, who agreed to join in an advisory capacity. Continuing his search for someone who would be a hands-on technical leader, he came across a physician by the name of Edward Orange Wildman Whitehouse.
Yes, physician, as in “trained in the repair of malfunctioning meat.” Whitehouse was another in a long line of self-taught electrical geeks. His claims of expertise rested mainly on his having built a telegraph in and around his home. His plan for getting a telegraph to function across the Atlantic was simple: To go far, use a really big battery: More volts = more miles. Simple. It was just a matter of scale.
It all sounded logical enough to paper magnate Field. At minimum, it was what he wanted to hear. Whitehouse’s confidence swayed the other investors as well and the project progressed rapidly. Every engineering challenge was seemingly overcome with surprisingly modest effort. For example the problem of insulating a cable from seawater had already been solved by the naturally thermoplastic rubber-like sap of the gutta-percha plant (found mainly in Malaysia). Gutta-percha was in the process of revolutionizing golf, having first found use in the core of golf balls in 1848. The
versatility of gutta-percha extended to its use in dentistry, where it continues to be used even today for temporary fillings. Of prime importance for Field was that no less an eminence than Faraday himself had found that immersion in cold saltwater at high pressure actually improves its electrical insulating qualities. Faraday’s work, in fact, had enabled construction of an underwater telegraph cable between Dover and Calais in 1851. The spanning of the English Channel with the 45km cable linked England with the rest of Europe. Whitehouse based his cable on that design, and asserted that the success of the Channel cable logically implied a simi-lar success with the Transatlantic cable. He repeated to the investors that it was sim-ply a matter of scale.
Although Whitehouse took the Channel cable as his model, he had some idea that his own cable would probably have to be somewhat larger. While a fatter cable has less electrical resistance (fatter pipe = easier flow), it also weighs more. Consider-ing that they had to span 3200km the total weight of the cable was a serious con-cern. A young physics professor at the University of Glasgow named William Thomson performed some calculations suggesting that, regrettably, a very thick cable would be necessary. No two ships in existence were large enough to carry all of Thomson’s cable, however, so Whitehouse ignored the egghead professor, citing his own “better living through voltage” solution to the problem. He did make use of one of Thomson’s other contributions, however. Amplifiers would not be invented for another half-century and even Whitehouse understood that there would likely be insufficient current to operate a conventional telegraph sounder. He was therefore happy to have the professor focus on the problem of developing a more sensitive receiver, although he would insist on trying out his own, inferior, receiver in com-petition with Thomson. As the story goes, Thomson was absentmindedly playing with his monocle when he noticed that sunlight reflected off of its brass frame to produce a wildly dancing spot of light on his study’s walls. Because movement of his monocle through a small angle produced a large lateral motion of the reflected spot, here was a sort of an amplifier. In short order Thomson glued some small magnets to the back of a tiny mirror and suspended the assembly on a fine thread. Current flowing through a nearby coil caused the mirror to rotate, deflecting the light from a kerosene lamp aimed at the mirror. A ruler measured the deflection, allowing one to detect the presence or absence of a telegraph key depression.
Thomson was delighted to discover that currents far too feeble to operate an ordi-nary sounder would still produce quite-detectable indications with his apparatus. Without his invention of the mirror galvanometer the transatlantic cable project would have had no chance of succeeding.
The chance of succeeding may have indeed been slim, but Whitehouse did his level best to drive it to zero by ignoring the recommendations of the only properly trained person associated with the venture. With his vast expertise in blood-letting and poultices to guide him, Whitehouse arbitrarily reduced the cable size until two ships could carry the load. After that, the only tough job would be to count all the money that the transatlantic telegraph would surely generate.
How could anything so simple fail to work?
The cable, though reduced in size by Whitehouse fiat, was still far too massive to be transported from a factory to the ships. The solution was to build a wire factory on shore, so that the cable could be loaded onto the ships as it was being made.
FIGURE 40. Cable being loaded aboard the Agamemnon (atlantic-cable.com)
The laying of the cable began in the summer of 1857 with two ships, the HMS Agamemnon from Britain and the USS Niagara from the US, each carrying half the cable.
FIGURE 41. HMS Agamemnon (left) and USS Niagara (right); Wikipedia
Trouble arose almost immediately. The cable snapped, was repaired and then snapped again. Apparently the mechanism that was supposed to maintain proper
tension on the cable was not working as planned. The decision was made to defer further attempts until a better cable-tensioner could be designed.
After a year of improvements, the team felt ready to try again. The Agamemnon and the Niagara met in the middle of the Atlantic on June 26. Engineers connected the two cables together, carefully insulated the splice with gutta-percha and signaled that the ships could proceed to their respective destinations. As the Agamemnon headed toward Ireland and the Niagara proceeded toward Newfoundland, the cable broke no fewer than three separate times. An exasperated Field halted the attempt until the problem could be studied further. Engineers improvised some adjustments to the cable tensioner and finally signaled to Field that they were ready to try again. The two ships proceeded carefully and by Aug. 5 both ends of the transatlantic cable had reached their respective destinations. The cable ends were hauled ashore and connected to the signaling apparatus. After a series of electrical tests, an offi-cial communication from Queen Victoria to President James Buchanan on August 16 marked the dawning of a new age. Raucous celebrations broke out in Britain and America and Field was hailed as the man of the decade, if not the century. The nat-ural human reaction, of course, was to compose polkas:
FIGURE 42. Got cable? Then polka!
Field’s celebratory mood was dampened by his knowledge that the 84-word com-munication from the Queen had actually taken 17 hours to send and decode. Many
retries had been necessary, and telegraphers had to guess at some of the text;55 something seemed to be wrong with the cable. Signals were weak and erratic.
55.The raw text as decoded on the American side was “Dear Jim, Good show. Let’s do lunch! -- Love and kisses, Vic,” leading to suspicion that interpolation was involved.
Worse, efforts to send text at even a modest rate resulted in an unreadable smear instead of discrete dots and dashes. They’d have to do considerably better than 10 minutes per word (that’s not a typo: 10 minutes per word).
As chief electrician, Whitehouse was under enormous pressure to fix the problems, so the medical doctor resorted to his brute-force “more volts = more goodness” for-mula. Ordering the addition of progressively more batteries to boost the signal seemed momentarily to improve communications but by the 23rd day after the inaugural communications, the doctor’s incompetence had proved lethal to the cable. Somewhere along the 3200 kilometer span, several kilometers beneath the surface of the ocean, excessive voltage had blown a hole through an internal piece of insulation and shorted out the cable.
Finger-pointing began immediately. Doubts even arose in some quarters about what was now being called the Queen’s “alleged” congratulatory message. Investors began to accuse Field of out-and-out fraud. “Cable deniers” claimed that the entire enterprise had been a grand scheme to separate fools from their money. Given how his life as a businessman had begun, these accusations hurt more than the technical failure of the cable itself. The British, having underwritten part of the attempt (and having also contributed the Agamemnon), convened a commission of inquiry to investigate what had happened and to assess whether another attempt would be per-mitted. Field and his failure were international news and none of it was favorable to Field.
Field was pained to see his name almost daily in newspaper headlines. He had gone from man of the hour to fraudster of the century, all in the span of a month. Fortu-nately for him, civil war broke out in the U.S. in 1861, pushing his name off of the front page for the duration.
The board of inquiry proceeded logically and deliberately while carnage swept the not-very United States (more than 600,000 soldiers died — over 2% of the entire US population and more than the US has lost to date in all of its other wars com-
bined). The board was shocked at several obvious problems. One was the choice of a medical doctor as head electrician. Another was the dismissal of William Thom-son’s calculations. Perhaps most astonishing was that there wasn’t even a vocabu-lary to describe the failure itself. Even butchers have words and associated standards for quantities like weight and volume, but there was no corresponding set of words and standards for the electrical arts. Eventually the creation of the volt, ampere and ohm would mark the emergence of a new profession — electrical engi-neering — all as a direct consequence of the cable’s failure.
As the Civil War drew to a close, so did the board’s work. Despite all of the errors of commission and omission, the board ultimately agreed that laying a cable across the Atlantic was technically possible. Willingness to fund yet another attempt was contingent on repairing the multiple deficiencies identified by the board, however. Tinkerers like Whitehouse were out and professor Thomson was named scientific head of the project.
Field promised to follow all of the board’s recommendations and so funds were provided for a final attempt. Thomson refined his calculations and concluded that a suitable cable would be quadruple the weight of the previous one. Ships of the Agamemnon/Niagara class would not be able to carry this cable, so additional ships (and risky cable splices) would be necessary. Thomson also investigated details such as the processing of the copper used in the cable, becoming enough of a metal-lurgist to understand the disproportionate sensitivity of copper to relatively small amounts of dissolved oxygen. Keeping the oxygen content low enough to minimize cable resistance would require careful manufacture, so Thomson oversaw the cop-per’s careful manufacture.
At this point, someone else’s colossal failure enabled the cable project’s ultimate success. The great civil engineer Isambard Kingdom Brunel had built bridges, ship-yards and Britain’s first large-scale railway system, the Great Western Railway
(along which, you may recall, Cooke and Wheatstone had deployed their ill-fated needle telegraph). One fine day, Brunel got it into his head that what the world really needed was a ship that could go from England to Australia without having to stop for coal. The capstone of his career was to build a ship so large that 4,000 pas-sengers at a time could enjoy the voyage. Regrettably Brunel had not bothered to carry out any careful market research. As it happened only about 11 paying passen-gers, all apparently named Earl, were interested in traveling nonstop to Australia, so the venture failed. A broken Brunel died in late 1859, leaving the gigantic ship he had designed, the Great Eastern, abandoned for lack of almost any practical use. Displacing 32,000 tons, a larger vessel would not exist until a half-century later, in the age of Lusitania-class vessels.
FIGURE 43. Brunel and the Great Eastern (note size of anchor chain links!)
The Great Eastern was so large, in fact, that its hold could carry the entire load of Thomson’s larger cable, with ample space to spare. The Project purchased it for pennies on the dollar, and it was quickly converted into a cable-laying ship. After a brief pause caused by Lincoln’s assassination on April 15, 1865, Great Eastern finally set sail from Valentia, Ireland on July 15, laying cable along the way. Engi-neers monitored the progress by continuously exchanging telegraph messages along the cable. As the Great Eastern faded from view at Valentia, communications continued uninterrupted, marking the first time in history that a ship hadn’t disap-peared when it disappeared.
A few problems arose here and there — including compass deviations caused by the massive amount of iron-jacketed cable, and suspicions of sabotage when sev-eral nail-like objects were found puncturing the insulating jacket. Fixes were improvised, guards were posted, and the voyage continued.
Success was only a day away when a rogue wave suddenly pitched the Great East-ern upward. The rapid rise increased tension on the cable and snapped it. The crew could only watch helplessly as the cable dropped thousands of meters into the dark waters below.
Field argued persuasively and successfully for funds to give it one last try. A year later, on July 13, 1866, Great Eastern sailed again, this time without incident. On July 27, after two largely problem-free weeks, the laying of the cable was complete. After many careful checks, congratulatory telegrams were again exchanged, now between Queen Victoria and President Andrew Johnson (“Dear Andy, Good show...”). An exhausted but relieved Field joined in the festivities, this time without worries.
The captain of the Great Eastern, James Anderson, started to search for the broken cable from the previous year’s nearly successful attempt. On August 9 he started dragging a grapple along the sea floor, hoping to snag the cable and bring it to the surface. He miraculously snagged the cable and brought it to the surface several times, only to have the cable slip off several times. In an amazing testament to heroic persistence he finally succeeded a month later. He was later knighted for his efforts. By September 7th, there were two functioning transatlantic cables. The United States and Great Britain have been in continuous contact ever since. In 1965, the hundredth year of operation, the still-intact transatlantic telegraph cable was ceremoniously decommissioned, having been made obsolete by advances in communication. The cable remains in place, however, just where Field and the Great Eastern put it more than a century ago.
Among its enduring legacies, the problems and success of the cable assured the cre-ation of a new profession: Electrical engineering. The activity had been a subset of subjects taught by university physics departments. The years immediately follow-ing the cable project’s final triumph saw an increasing number of schools making plans for separate electrical engineering departments in acknowledgment of the subject’s growing importance as a discipline in its own right. By the early 1880s, schools such as Cornell University and the Massachusetts Institute of Technology were offering courses of instruction and degrees in electrical engineering.
As for Field himself, the Transatlantic Cable Company charged $10 per word (per-haps equivalent to $500-$1000 today), and Field rapidly became wealthy beyond all dreams of avarice. He should’ve retired in comfort but, alas, he later bet essen-tially every dollar he had on speculative stocks. He lost those bets and died nearly penniless in 1892 at the age of 72. If it hadn’t been for the diligence of his sons, the family would have been destitute. Perhaps it is because of this unhappy end to an otherwise glorious tale of persistence prevailing against all odds that Field’s name is little known today. He deserves better.
Queen Victoria elevated Thomson to the peerage for his invaluable contributions to the project. He went on to important achievements in the field of thermodynamics
(as we’ll see later), and is better known today as Lord Kelvin (First Baron Kelvin of Largs). The unit of absolute temperature, the kelvin, is named in his honor.
Thanks to Field and Thomson (and the Great Eastern) all continents would be linked by telegraph by the first decade of the 20th century, in a prefiguring of the modern interconnected world that we now enjoy.
Faraday suffered increasingly from serious ailments in his later years, with symptoms consistent with a lifetime of exposure to toxic metals (mercury chief among them). Although he lived to see the transatlan-tic cable laid, none of his surviving correspondence mentions it. Had he been well enough to comprehend what Field and Thomson had accomplished, he might have allowed himself to feel pride at having made the enterprise possible in the first place. Given his Sandema-nian sensibilities, of course, any such pride would have found expres-sion as admiration for what Field and Thomson had achieved.
Faraday had managed another critically important achievement a decade or so before passing away in 1867. He had begun a correspondence and friendship with a young Scottish physicist, James Clerk (pronounced “Clark”) Maxwell, who was the trained mathematician that Faraday was not. One of Maxwell’s first papers, pub-lished in 1855 when he was 24, was titled, “On Faraday’s Lines of Force.” His translation of Faraday’s intuitive ideas into the quantitative language of mathemat-ics not only did much to elevate Faraday’s stature in the eyes of the formally schooled, it was also an important first step toward fulfilling a dream of Faraday
who, like Oersted, believed that all “powers” derived from a common source. That belief, plus his remarkable intuitive insights about the workings of nature, had left him with a conviction that light itself had to be an electromagnetic phenomenon. He had even carried out a number of experiments in an effort to prove it, but with-out much success. He attributed these failures to the experiments themselves, and not to any fault with his hypothesis.
In conveying his beliefs to Maxwell, Faraday was passing the torch to perhaps the one individual then alive who could succeed in the endeavor. Maxwell began by systematically writing down the equations that summarized all that was then known about electricity and magnetism. That part was easy, because there weren’t that many equations. Ampere had provided the mathematical description of how an electrical current could generate magnetism. To that Maxwell added his own math-ematical description of Faraday’s discovery that a changing magnetic field gener-ates an electric field. Maxwell could tell by inspection that this apparently comprehensive set of equations could not describe light. However, inspired by his belief in Faraday’s vision, Maxwell pressed on, almost arbitrarily adding one more equation to produce the desired miracle. The added term was equivalent to declar-ing that a changing electric field could generate an electrical current. There was then no experimental evidence to justify this declaration, but he pressed on, for he recognized that the resulting set of equations described an electromagnetic dog chasing its magnetoelectric tail: A changing magnetic field would give rise to a changing electric field, which would give rise to a changing magnetic field, and so on, with the dying of one generating the other. The equations described an electro-magnetic wave as an eternal dance of mutual destruction and rebirth. They described light.
Maxwell was not an experimentalist. He wasn’t even able to suggest how to go about setting up any relevant experiments — let alone carry them out — to provide direct, physical proof that his equations were correct. However, his equations did imply one specific — and previously unsuspected — relationship among light, electricity and magnetism. By his reckoning, the speed of light should be express-ible in terms of two separate physical constants — one each from Ampere’s and Faraday’s laws. When he plugged the best-known values for these constants into his formula, what emerged was a velocity that was within 5% of the speed of light. To him, that level of agreement couldn’t be a coincidence. Light was almost cer-tainly an electromagnetic wave. The calculation had yielded a tantalizing clue, but “almost certainly” was unsatisfyingly short of “certainly.”
And that’s where things stood for over a decade, for Maxwell regrettably did not enjoy Faraday’s longevity. It is a tragic loss to our species that Maxwell died of
stomach cancer at the age of 48, the same age that his mother died of the same ail-ment. Others would have to provide direct proof of his equations.
Maxwell’s equations would eventually give us wireless technology. And, in the spirit of rebirth following death, Maxwell’s work would also inspire a young physi-cist named Albert Einstein — born in the year of Maxwell’s death — to a revolu-tion in our understanding of the universe. These developments would be so profound that the physics Nobelist Richard Feynman has opined that the US Civil War would eventually fade into merely parochial significance, but Maxwell’s equa-tions would forever be acknowledged as the crowning intellectual achievement of the 19th century.
The nine-month gestation had been fraught with one serious problem after another. Now the wait was finally over and Federico Faggin – at various times father, mother and midwife – expectantly approached his newborn. Hope tempered with trepidation quickly bubbled over into elation as waveform after waveform happily revealed the lusty cries of a healthy infant: The 4004 was alive and well! It was cer-tainly a promising start for the microprocessor, but not even the other parents of the 4004 — Stan Mazor, Ted Hoff and Masatoshi Shima — could imagine just how promising. With astonishing speed, its descendants would completely transform human existence.
The Age of Mechanism
Had we known then what we know now, the birth of the microprocessor that Janu-ary day in 1971 might have been celebrated the world over. Perhaps, as with the first transatlantic telegraph cable and with Telstar — the first communications sat-
ellite — the achievement would have inspired verse and song. Raucous brass bands would have accompanied fireworks and parades. And had carillons competed with that exuberant cacophony for attention, it would have been particularly apropos, for our story traces back in part to the mechanisms used to automate their playing.
When the art of modern clock-making began to develop in Europe in the 13th and
14th centuries, the mechanisms initially marked time by sounding a bell (typically once or twice an hour), rather than providing a continuous display of time with the now-familiar hour- and minute-hands [1]. These early clocks usually rang a single bell, but a delightful musical tradition arose primarily in the “Low Countries” of Holland and Belgium. Anyone who has examined the mechanism of an old-fash-ioned music box will recognize the barrel-and-pin arrangement eventually devised to automate the playing of the carillon bells (Figure 1). As the clock mechanism rotates the barrel, protruding pins strike levers that ultimately activate combinations of bells in the corresponding sequence. Playing a particular tune merely involves the insertion of pins in an appropriate pattern. The simplicity and flexibility of this arrangement greatly facilitates the accommodation of a variety of musical sequences. Paper maps of the pin locations provide a nonvolatile memory of indi-vidual musical selections, and enable rapid setup of new tunes. The template thus represents a primitive but definite form of data storage, distinct from the mecha-nism (execution engine) that acts on the stored information.
FIGURE 44. Automatic carillon mechanism in the belfry of Ghent. (Photo credit: Essentialvermeer.com.)
The next evolutionary step toward the computer takes us from Flanders to France. Basile Bouchon of Lyon solved a problem in the textile industry in 1725 by adapt-ing key aspects of the pin-and-barrel system. Bouchon’s father was an accom-plished organ builder and familiar with automated carillons. The younger Bouchon reconceived the pin-and-barrel as a perforated paper cylinder that could control the patterns woven by looms. The invention enabled higher speed, better consistency, and the accommodation of more intricate patterns. The fragility of perforated paper motivated Bouchon’s associate, Jean Falcon, to substitute a chain of sturdy punched cards for paper in 1728. This arrangement also had the advantage of easily allowing editing of the programmed patterns, since individual cards could be exchanged without having to replace the whole set.
Bouchon’s inspired adaptation greatly improved throughput and quality, but the process was still incompletely automated: a human had to advance the template manually, line by line. It was too easy for a fatigued or distracted weaver to forget to do so from time to time, possibly ruining a piece. A fellow countryman, Jacques Vaucanson, solved that problem logically enough with an automatic advance mech-anism in 1745. The seemingly inevitable and obvious next step of combining Fal-con’s card assembly with Vaucanson’s automatic advance system inexplicably took a half century. Joseph Marie Jacquard finally took that last step, in 1801.
FIGURE 45. Left: Loom with Jacquard head, at the Manchester Museum of Science and Industry. Right: Closeup of cards.(Wikipedia; photo credit: George H. Williams)
The Jacquard loom (more properly, the Jacquard head, as Jacquard did not modify the loom proper) did indeed revolutionize the textile industry, but not in France. Another revolution had recently taken place there, and it significantly muted the domestic demand for the patrician patterns that Jacquard’s invention made practi-cal. Instead, the Jacquard loom found a welcome home in England, where it made once-exotic patterns, such as paisley, widely available for the first time.
The Jacquard loom and the French revolution had consequences that extended well beyond textiles. The Revolution had caused a spike in hairdresser unemployment, owing to fewer heads as well as a reduced demand for the elaborate hairstyles of the detested upper class. Gaspard Clair François Marie Riche de Prony decided to put many of these hairdressers to work as computers in the 1790s, to generate logarith-mic and trigonometric tables. He organized them systematically into teams, each of which was responsible for a particular computational module. He thus anticipated the mass-production methods that would later dominate manufacturing. De Prony noted with satisfaction that these computers did an excellent job.
Around 1822 Charles Babbage (later to hold the Lucasian professorship of mathe-matics at Cambridge, as Newton once had) began developing ideas for a purely mechanical calculating machine [3][4]. He was motivated in part by frustration with the errors inevitably found in published mathematical tables. Eliminating the human element was essential to achieving his goal of perfection, and he drew inspi-ration from de Prony’s organization of human computers in architecting his own mechanical computer. His Difference Engine was to generate tables of logarithms and trigonometric values automatically, using a particular mathematical approach (the “method of finite differences”) to calculate polynomial approximations of these functions. He elaborated on these concepts in the design of the vastly more powerful Analytical Engine. It was to use two sets of Jacquard’s punch-cards — one to specify the operations (program), and another for the data on which the pro-gram would operate. Neither Engine was built in his lifetime, but the concepts underlying their operation are breathtakingly modern. Particularly noteworthy per-haps is his explicit recognition of conditional operators as valuable.
A working Difference Engine was finally demonstrated in 1991, as part of a bicen-tennial celebration of Babbage’s birth. It took almost another decade to realize his concepts for the associated printing mechanism. Figure 3 shows the completed Dif-ference Engine on display at the London Science Museum. There are no known plans by anyone anywhere to build an Analytical Engine.
FIGURE 46. World’s first working Babbage Difference Engine, at the London Science Museum. The printing mechanism is on the left. The operating crank for the Engine is seen on the right. (Wikipedia: Difference Engine.)
Babbage died in 1871, just a few years too soon to see his idea of using Jacquard’s (Falcon’s) cards for data storage adopted by government bureaucrats desperate to solve a different set of problems.
Our Friend, the Electron
John Shaw Billings was a supervisor for the 1880 U.S. census, and he saw serious trouble ahead. Manual tabulation of the data was so slow that completing the 1880 census took nearly eight years. Billings and his colleagues estimated that the next census would take half as many years longer, so it was evident to all that the meth-ods they’d been using had reached a scaling limit. Belying the stereotype of an indifferent, slothful bureaucrat, Billings took action, just as he had during the U.S. Civil War, where he’d served as medical inspector of the Army of the Potomac, and just as he had in establishing the New York Public Library. He’d proved his powers of persuasion in convincing steel magnate Andrew Carnegie to fund the construc-
tion of thousands of public libraries, so he was the right man to get one of his subor-dinates, Herman Hollerith, to look into ways of mechanizing the process to speed up the next census. Hollerith went to work immediately, and in short order invented an electrical tabulator based on Jacquard’s punched cards (see Figure 4) [5][6]. The card reader (see closeup on the right) used a movable “bed of nails” to make electri-cal contact through card holes to mercury-filled wells in the base.
FIGURE 47. Hollerith census tabulator, at the Computer History Museum. Dials indicate current and total values of individual data fields. Punch cards would be used with computers well into the 1970s. (Photos by author)
To save time and money, Hollerith chose dimensions for the card that matched those of the U.S. dollar bill at the time, allowing him to use components and whole assemblies from pre-existing machines. Thanks to the speed and accuracy of Hol-lerith’s electrical tabulator, the 1890 census was finished in little over half the time of the 1880 census, and that included a complete second run needed to overcome skepticism about this new way of doing things. Hollerith’s Tabulating Machine Company became the International Business Machines Corporation in 1924 after a series of acquisitions and mergers. History records that a company called IBM enjoyed some prominence in the computer business.
Aspects of Babbage’s work also ultimately inspired the creation of an analog mechanical computer, the Differential Analyzer (Figure 5) [7][8]. Vannevar Bush, Harold Hazen and their colleagues began working on the Analyzer at the Massa-chusetts Institute of Technology in the late 1920s, and were able to demonstrate an operational unit by the early 1930s. Capable of solving sixth-order differential equations, the versatile Analyzer was suitable for everything from early quantum calculations to generating ballistics firing tables. The technical success of the MIT Analyzer led to the adoption of the architecture at a number of other institutions. The installation at UCLA is perhaps especially noteworthy for its contribution to popular culture: The proximity to Hollywood helps explain why the UCLA Ana-lyzer appears in movies such as When Worlds Collide and Earth vs. The Flying Sau-
cers. These films, dating from 1951 and 1956, respectively, attest to the iconic status of the Analyzer in the early postwar period.
FIGURE 48. Vannevar Bush (left) examining the Differential Analyzer in operation. (Photo credit: MIT Department of Electrical Engineering and Computer Science)
As powerful and flexible as the Analyzer was, it did suffer from several deficien-cies. “Programming” the Analyzer involved disassembling the previous setup, and reassembling the new configuration of gears and linkages, for example. Merely set-ting up a problem for solution often took days of wrench-work that would’ve been more familiar to automobile mechanics than to mathematicians. Indeed, computing the solution often took less — sometimes much less — time than it took to set up the Analyzer.
Inevitably, students were impressed into service as make-do mechanics to config-ure, operate and maintain the Analyzer. One of these students was Claude Shannon, who had recently started his graduate studies at MIT after earning two bachelor’s degrees (in mathematics and electrical engineering) at the University of Michigan in 1936. By 1937, Shannon’s experiences with the Analyzer had motivated him to invent the technology that would soon render obsolete the Analyzer and its mechanical kin: digital electronics. Shannon was familiar with the then-obscure work of George Boole [9], and realized that Boole's concepts could be applied to the analysis and design of what we now call digital circuits. A 1938 paper derived from, and titled the same as, his 1937 master's thesis, “A Symbolic Analysis of Relay and Switching Circuits,” was immediately influential [10]. For virtually all readers, it was their first exposure to the names and powerful ideas of Boole and Augustus De Morgan. Shannon’s paper presented a rich formalism that transformed into an engineering discipline what had previously been an ad hoc art. Considering all that has followed from this work, it’s difficult to argue with the common assess-
ment that it was the most important master's thesis of the 20th century.
Once binary logic was understood by a critical mass of engineers, it was only a matter of time before fully electronic computers would turn their electromechanical counterparts into museum pieces. Abetting that transition was the work of Alan Turing. At virtually the same time that Shannon was inventing digital electronics, Turing was establishing some of the foundational ideas of computer science. Per-haps chief among these was the concept of a universal machine (known today as a Turing machine) that could implement any function that was computable. Such a universal machine is now known as a Turing-complete computer. The influence of Turning’s ideas took somewhat longer to be felt, but that influence has been no less profound than Shannon’s.
The demands of the Second World War greatly accelerated the development of vir-tually all technologies. Computers both aided, and were aided by, these develop-ments in no small measure. Only electromechanical analog computers had existed before the war. By the war’s end, electronic computers with recognizably modern characteristics had come into existence, with fully digital programmable electronic computers following soon after.
In Germany, Konrad Zuse constructed a succession of digital computers based on relay logic. His third, dubbed the Z3, executed programs stored on paper tape, and was operational by 1941. It was the first program-controlled digital computer pos-sessing all of the essential characteristics of what we think of as a modern com-puter. Specifically, it was the first “Turing complete” machine [11]. (Although no computer with finite memory can be Turing complete in the formal sense, the term is colloquially applied to computers that would be complete if infinite memory were available.) A reconstructed Z3 is on display at the wonderful Deutsches Museum in Munich.
At approximately the same time as Zuse was demonstrating his relay-based Z3, Clifford Berry and John Atanasoff of Iowa State College were building an elec-tronic computer designed to solve systems of linear equations. As did the Z3, the Atanasoff-Berry Computer (ABC) used binary arithmetic. It also used dynamic memory based on capacitive storage cells, properly implementing the necessary refresh operations. Robert Dennard of IBM would reinvent capacitive dynamic memory in integrated circuit form almost three decades later [12]. Although the ABC was not programmable, its innovations were nonetheless influential. The degree of this influence was the subject of protracted litigation that finally con-cluded in favor of the ABC team in 1973. Although the litigation may have ended, the arguments clearly have not [13][14].
The war naturally also stimulated intense activity in the U.K. At Bletchley Park, a secret effort dedicated to cracking German codes produced the Colossus computer in 1944. It holds the distinction of being the first programmable digital electronic computer. Somewhat ironically, however, it was not Turing complete, even though Turing worked at Bletchley Park. The influence of the Colossus on subsequent computer development was limited because of the secrecy that enshrouded the work. Indeed, all ten Colossus machines in use by the end of the war — and all associated engineering documents — were deliberately destroyed after the war, on orders from Winston Churchill himself. The world at large thus knew nothing of the
Bletchley Park achievements until the 1970s. Surviving alumni of the effort helped to reconstruct the Colossus from memory, with success achieved in 2006 [15].
A computer of the era that did have great influence was the decimal-based ENIAC (electronic numerical integrator and computer). The project that gave life to ENIAC began with John Mauchly’s pre-war desire to build a weather-forecasting computer. The University of Pennsylvania professor redirected his efforts after war broke out, to design a computer that would carry out the same sort of ballistics cal-culations that the Differential Analyzer could perform. Mauchly understood that an electronic computer would be able to outperform a mechanical one by orders of magnitude. Working with J. Presper Eckert, the ENIAC became operational at the university’s Moore School of Electrical Engineering laboratories in 1945; it was the first Turing-complete electronic computer [2]. Its complement of nearly 18,000 vacuum tubes helped account for its 150kW power consumption (and a mean time between failures of a day or two). It could multiply two 10-digit decimal numbers in a few milliseconds. A few hundred multiplications per second may be laughable performance today, but it astonished at the time.
FIGURE 49. ENIAC in operation (Wikipedia). The rat’s nest of patch cables used to program the computer are clearly visible on the left.
ENIAC begat EDVAC (Electronic Discrete Variable Automatic Computer; clearly the Department of Cumbersome Acronyms was working overtime) at the Moore School. John von Neumann authored an influential report on EDVAC, in which he elaborated on some of Turing’s ideas. Unlike the decimal-based ENIAC, EDVAC
would be a binary digital computer, and program instructions would share memory with operands. This shared-memory structure is now known as the von Neumann architecture, thanks to his sole authorship of the report. This assignment of credit has been a source of annoyance to others working on the project, Mauchly and Eck-ert included [14]. Perhaps it is sufficient to note that success has many fathers, and grand successes tend to stimulate many claims to paternity.
Mauchly and Eckert left the university to start their own computer company, the Eckert-Mauchly Computer Corporation. Through an acquisition in 1950, EMCC became the Univac division of Remington Rand. The UNIVAC computer gained fame for accurately predicting the outcome of the 1952 presidential election, where human pollsters had not. Television network CBS had chosen to include UNIVAC in their broadcast coverage largely as a publicity gimmick, and simply disbelieved the machine’s predictions until hard data revealed that UNIVAC had been correct all along. Later in the broadcast, news anchor Walter Cronkite apologized on cam-era. Overnight, the idea of an omniscient electronic brain gained currency in the popular imagination. The 1957 Tracy-Hepburn film, Desk Set, plays on this notion, and in fact opens with a sequence that features an IBM 650-series computer (the first mass-produced computer) printing out the credits. IBM’s computers would famously come to dominate the mainframe world.
The evolution of the computer during this fertile period is mirrored in the rapidly evolving etymology. Until the electronic age, a computer was a human who did cal-culations [16]. When devices such as the Analyzer appeared, the qualifier mechani-
cal had to be added to distinguish the new from the old. The arrival of a still-newer technology was acknowledged by the establishment of MIT’s Digital Computer Laboratory in 1951. The subsequent dominance of digital computers eventually made the qualifier digital unnecessary, and the retronym analog computer was cre-ated to distinguish the old from the new. Today, a computer is a digital computer in all but a very few cases.
The links connecting UNIVAC to the 4004 include the first transistor computers, the TX0 and TX2 — built at MIT’s Lincoln Laboratory — and the miniaturization that transistors made possible. That miniaturization in turn kicked off the minicom-puter revolution, led by Digital Equipment Corporation, whose founders, Ken Olsen and Norm Andersen, had worked on the TX0. Their PDP-1 debuted in 1958, and its interactive and more personal type of computing inflamed a desire among engineers for still-smaller, even-more personal computers. With the invention of the integrated circuit soon after DEC’s founding, the basic elements were in place [17]. After a few generations of Moore’s law, and a small additional stimulus, the microprocessor would be all but inevitable. By 1970, with Busicom’s desire to
make calculators, and Intel’s desire to sell them chips, the necessary conditions were well satisfied.
Summary
As with all human stories, the path to the microprocessor was anything but a straight line. Bits of art scattered over the globe and across centuries somehow assembled organically to drive the narrative of this history. The random nature of creation forces us to impose an a posteriori order that is arguably more of a Ror-schach test than an objective recounting. Instead of starting with carillons, we could have gone further back in time, to Heron of Alexandria, whose virtuosity with mechanism included the construction of devices that are the direct ancestors of the pin-and-barrel. We also could’ve examined the contributions of Ada Byron King, Countess of Lovelace, and her work with Babbage, or about the profound influence of Turing’s ideas, but one must bound the story somehow, especially in a chapter of a few pages. It is hoped that the incompleteness does not undermine the basic thesis that, although the microprocessor may have been inevitable, the particular path connecting it to automated carillons was probably not unique. If we were to re-run the tape of history, it is unlikely that events would unfold in the same manner again. But let the carillons chime in celebration, just the same.
References
1. Thomas H. Lee, “It's About Time: A Brief Chronology of Chronometry,” IEEE
SSCS Magazine, July 2008.
2. Herman H. Goldstine, The Computer from Pascal to von Neumann, Princeton University Press, 1980.
3. Charles Babbage, “A note respecting the application of machinery to the calcu-lation of astronomical tables,” Memoirs of the Royal Astronomical Society of
7. Thomas H. Lee, “Tales of the Continuum: A Subsampled History of Analog Circuits,” IEEE SSCS Magazine, October 2007. Ancestors of the MIT Differen-tial Analyzer include the work of William Thomson (later to become Lord Kelvin). In turn, Thomson’s work represents a re-establishment of an analog computing tradition that dates back to the Antikythera mechanism of Roman times.
9. George Boole, An Investigation of the Laws of Thought, Macmillan, Lon-don,1854. It may be downloaded in a variety of formats from http://www.archive.org/details/investigationofl00boolrich.
10. Claude Elwood Shannon, Transactions of the American Institute of Electrical
Engineers, vol. 57, pp. 713-723, 1938. His complete master’s thesis (dated 10 Aug. 1937) may be downloaded from http://dspace.mit.edu/bitstream/handle/1721.1/11173/34541425.pdf?sequence=1.
12. Robert H. Dennard, “Revisiting Evolution of the MOSFET Dynamic RAM - A Personal View,” IEEE SSCS Magazine, Jan. 2008. His article implies that he was unaware of the ABC’s use of dynamic memory.
13. The Trial, http://www.scl.ameslab.gov/ABC/Trial.html, retrieved 1 Nov. 2008.
14. “Q&A: A lost interview with ENIAC co-inventor J. Presper Eckert,” Computer-
