Gustav Mie: the person

Pedro Lilienfeld

About 25 years ago, when I became acquainted with the name Gustav Mie, I was unable to find an entryfor him in such major encyclopedias as the Britannica or even in several listings of famous scientists [T. I.Williams, A Biographical Sketch of Scientists (Wiley, New York, 1967); J. Turkevich and L. Turkevich,Prominent Scientists of Continental Europe (Elsevier, New York, 1968)]. This puzzled me indeed when Iconsidered that Mie's 1908 paper and the terms Mie scattering and Mie effect were and continue to becopiously cited in the literature on particle light scattering. One can find few issues of Applied Optics, theJournal of Aerosol Science, Aerosol Science and Technology, and many related publications that do notmention Mie. Yet he is a shadowy figure, almost a disembodied three-letter name without much realexistence. Within this biographical note, I try to put some flesh and bones on that apparently ghostlyscientist.

Key words: Biographical note, Mie scattering.

Gustav Adolf Feodor Wilhelm Ludwig Mie was bornin 1868 in the northern German city of Rostock. Hedied at the ripe old age of 89 in 1957 in Freiburg imBreisgau.

In a brief autobiographical sketch written in 1948,'he states that he descends from Protestant pastorfamilies on both his father's and mother's side andthat his un-Germanic family name originated in 16thcentury Huguenot France from which his forefathersfled religious persecution. Ironically, the only entryon Mie that I eventually found in a dictionary offamous scientists2 erroneously states that he was theson of a pastor. Mie himself informs us that his fatherwas a kaufmann, a merchant, although his twograndfathers as well as several of their predecessorshad indeed been clergymen. In the 17th century hismother's family was also driven by religious intoler-ance from Austrian Salzburg into German Wfirttem-berg. He had three brothers (one became a pastor inScharnebeck) and a sister.3

Mie spent his early years in the old Hanseatic portof his birth in a traditional religiously oriented familyenvironment, which initially appeared to lead himtoward the study of theology. At the age of 16 heconfronted, for the first time, the intellectual conflictbetween his strong religious upbringing and thescientific challenges of Haeckel and Darwin. Al-

The author is with MIE, Inc., 213 Burlington Road, Bedford,Massachusetts 01730.

Received 19 April 1990.0003-6935/91/334696-03$05.00/0.o 1991 Optical Society of America.

though the lure of a career in the exact sciencesprevailed by the time of his high school graduation,Mie's strong religious beliefs persisted and influencedhis work throughout his long life. He also asserts thatKant's Critique of Pure Reason had a long-lastinginfluence on his thoughts and that he literally bangedhis head repeatedly against a wall to master the moreknotty passages of that treatise.

His first two years of higher education were spentat the University of his native Rostock. In 1888, hesought a broader academic environment by transfer-ring to the renowned University of Heidelberg wherehe concentrated on mathematics and mineralogy. Miestates in his autobiographical notes that, although hewas by then keenly interested in physics, theoreticalcourses in that field were still not available at Heidel-berg or at most other major German universities ofthe time.

With characteristic dedication he immersed him-self in various physics textbooks during vacations inRostock so that by 1890 he could apply for theso-called State Examination for Mathematics andPhysics. He was assigned to prepare a dissertation oneach subject. He describes how he spent severalmonths writing the physics assignment and was leftwith one day to prepare the mathematics thesis. Hedid so by working 24 hours with minimal interrup-tion. Afterward he was accepted for the verbal exami-nation in Karlsruhe in the Spring of 1891. Later thesame year he obtained a doctorate with a dissertationon a "Very abstract problem of partial differentialequations."' For a few months in 1892 he taughtmathematics and natural sciences at a private school

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Fig. 1. Gustav Mie (photograph courtesy of H. Spehl, Albert-Ludwigs-Universitat).

in Dresden. From there he sent a copy of his doctoralthesis to his old physics professor, Otto Lehmann, atthe Technische Hochschule in Karlsruhe. He promptlygave Mie an assistantship to lead the physics labora-tory training (physicalisches Praktikum), and shortlyafter this he was called to help in the preparation ofexperimental lecture demonstrations. Concurrently,he worked on the replication of the electromagneticexperiments of Heinrich Hertz. He used the actualinstruments developed by that scientist some 5 yearsearlier, which were part f the collection of theKarlsruhe Physics Institute. He was required, how-ever, to solidify his theoretical physics background toobtain the lectureship (Habilitation) that he receivedin 1897. Mie attributes his first widespread recogni-tion by the scientific community as a theoreticalphysicist to a paper on the propagation of electricfields along two parallel conductors,4 which was pub-lished around that time.

In 1901 he married Berta Hess (1875-1954),3 whomhe met during his Heidelberg days, and the subse-quent year he assumed a special professorship post(Extraordinarius) at the University of Greifswald,not far from and to the east of his native Rostock. AtGreifswald he wrote his paper on particle light scatter-ing that made him famous. It is worthwhile to ponderthe origin of that paper,' which was published in 1908in the Annalen der Physik, bearing the title "Beitrdgezur Optik TrUber Medien, speziell kolloidaler Metall6-sungen (Contributions to the optics of turbid media,especially colloidal metal suspensions)." Paradoxi-cally, the importance of the 69-page paper appears to

have been greatly underestimated by both its authorand contemporary scientists. Indeed, Mie mentionsneither this paper nor any of his investigations onlight scattering by small particles in his autobiograph-ical notes. Mie considered that his salient contribu-tion to science was a textbook on electricity,6 firstpublished in 1910, in which he prides himself onhaving been able to describe Maxwell's theory onelectromagnetic propagation without the use of equa-tions, a somewhat paradoxical endeavor consideringthat his 1908 paper on particle scattering contains noless than 102 sets of equations. How familiar aremany of today's scientists with the actual content ofthis paper beyond the customary ritual of using it as areference? Its translation into English from its origi-nal German has not had wide circulation, and, as theabove-mentioned mathematical content suggests, itwas not intended for superficial browsing.

It appears, at least to me, that Mie's 1908 paperrepresents a single major involvement with the sub-ject of particle light scattering and absorption. It wastriggered (as suggested by Kerker7 ) by the experimen-tal investigations on colloidal gold suspensions by astudent (Walter Steubing) at the Greifswald Insti-tute, to which Mie refers in the introduction to thatpaper. Steubing's dissertation was published in theAnnalen der Physik8 a few months after Mie's paperwith the title "Uber die optischen Eigenschaftenkolloidaler Goldl6sungen (On the optical properties ofcolloidal gold suspensions)." The author acknowl-edges his mentor's role as follows: "To conclude, Iwould like to express my heartfelt gratitude to Prof.Mie, on whose suggestion I undertook this Work, forhis steadfast and friendly interest and for his kindadvice."

It is noteworthy that the analysis presented inMie's paper is restricted to particle diameters up to0.18 plm, a limit possibly related, to Steubing's goldcolloids. Thus we may speculate that Mie decided todevelop a rigorous theoretical interpretation of theempirical results obtained by that researcher, whichwere based on Maxwell's equations on whose physicalramifications Mie had concentrated his attentionsince at least 1896. Here, at Greifswald, the notedresident Maxwellian specialist was called on to extendthat theoretical framework to include the interactionof electromagnetic waves 'and particles whose sizeapproaches the length of these waves. He proceeded,however, beyond the original intention of merelyexplaining the colors of colloidal gold observed bySteubing. But there it rested, and the last of theconclusions in this extensive paper states: "Thethorough understanding of the theory will requirethe study of the behavior of ellipsoidal particles." Miewas to live for another half-century without publish-ing any additional material on particle light scatter-ing.

Mie pursued his work at Greifswald over a period of15 years, which he characterized as happy and scien-tifically productive. He singles out a major endeavor

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that engaged him at Greifswald: his unsuccessfulattempt at developing a comprehensive Theory ofMatter, wherein Maxwell's equations were to beconsidered as limiting cases of a more general theory,based on the overall concept of a world-ether(Weltather) consisting of the matter-energy contin-uum wherein elementary particles (i.e., atoms) are tobe considered as energy nodes."' This pursuit was, asMie suggests, inspired by the theory of relativity,which drew his attention for many years hence andremained a subject that he was to write about exten-sively.'2

He recounts with nostalgia that during his Greif-swald years, and until the onset of World War I, everyMarch he joined the well-known physicist Wien at hisalpine retreat for cross-country skiing excursions.They were joined by other outstanding German andDutch Physicists, such as Sommerfeld, von Laue, andDebye.

In 1917 he received an offer from the University ofHalle where he stayed until 1924. These were turbu-lent years in that city, which was disrupted by leftistrevolts, rightist military takeovers, sieges, and pitchedbattles, all followed by rampant inflation. Neverthe-less, Mie enjoyed his stay at Halle whose environmentof interdisciplinary cross fertilization he found intel-lectually stimulating. In the spring of 1924 he wasinvited to join the faculty at the University of Freiburgim Breisgau in southwestern Germany where hespent the rest of his academic life. In 1935 he retiredfrom lecturing and received the title of ProfessorEmeritus. In Freiburg he cofounded a scholarly soci-ety called the Pentathlon (because of the five extantfaculties at the University of Freiburg), which, how-ever, was dissolved shortly after Hitler came topower, since one of the other two cofounders was theJewish philosopher, Jonas Cohn, who had to fleeGermany.

He bemoans the difficult times under Hitler, fol-lowed by World War II, and "for us Germans, itsdeplorable ending." In Mie's defense, he seems tohave been, if not explicitly anti-Nazi, at least detachedfrom the pseudoscientific hysteria of the GermanPhysics of that period.

He spent the last years of his life in quiet butintellectually active retirement in Freiburg as a se-nior patriarch of the physics community of his coun-try. He was honored by his colleagues at the Univer-sity and participated in Protestant church-relatedgatherings against the backdrop of a predominantlyCatholic community. This religious involvement hadaccompanied his entire professional life and probablyled him to pursue all-encompassing and transcenden-tal theories of matter and energy that were compati-ble with his religious views. Several of Mie's writingsin the 1930's and 1940's were published under thetitle "The Divine Order in Nature," where he advo-cated a synthesis between Christian beliefs and thenatural sciences.'3

Mie's main contributions to science, in addition tohis oft-cited light-scattering paper, require recogni-tion. He derived inductively the Maxwellian edificefrom the empirical reality, a pursuit that still occu-pied Mie in his 80th year when the last and revisededition of his Handbook of Electricity and Magnetismwas published.'4 His persistent search for a unifiedtheory encompassing field and matter, although un-successful, nevertheless stimulated the work of othernotable physicists such as Born'5 and Infeld. Otherimportant pursuits by Mie included research into thedielectric constants of various materials using electro-magnetic waves; the solution of the problem of theanomalous dispersion of water leading to the determi-nation of the characteristic dielectric constant of thatliquid; and x-ray crystallographic studies of hydratednaphthalenes, anthracenes, and polyoxymethylenesand of liquid crystals.

Mie, the person, appears to have been a gentle andavuncular savant, who was respected by his peers andled a largely noncontroversial, secluded, and some-what isolated life. Even during the apogee of hisacademic career he remained on the periphery of theuniversity environment, without the expected entou-rage of graduate students and doctoral candidatesthat surround the archetypal Herr Professor. One ofhis assistants wrote on the occasion of Mie's 100thanniversary'6 that he had been "a profound thinker, anotable researcher and a kind human being. "

References1. G. Mie, "Aus meinem Leben," Zeitwende 19, 733-743 (1948).2. J. Mehra, "Mie, Gustav," in Dictionary of Scientific Biography

(Scribner, New York, 1974), Vol. 9, p. 376.3. H. Spehl, "Gustav Mie," Badische Biographien B. Ottnad, ed.

(Kohlhammer-Verlag, Stuttgart, 1990), Vol. III.4. G. Mie, "Elektrische Wellen an zwei parallelen Drihten," Ann.

Phys. (Leipzig) 2, 201-249 (1900).5. G. Mie, "Beitrige zur Optik trUber Medien, speziell kolloidaler

Metall6sungen," Ann Phys. (Leipzig) 25, 376-445 (1908).6. G. Mie, Lehrbuch der Elektrizitdt und des Magnetismus (F.

Enke, Stuttgart, 1910).7. M. Kerker, The Scattering of Light and Other Electromagnetic

Radiation (Academic, New York, 1969), p. 55.8. W. Steubing, "Uber die optischen Eigenschaften kolloidaler

Goldl6sungen," Ann. Phys. (Leipzig) 26, 329-371 (1908).9. G. Mie, Molekiile, Atome, Weltdther (Tuebner, Leipzig, Ger-

many, 1904).10. Ref. 9, 2nd ed. (1907).11. Ref. 9, 3rd ed. (1911).12. G. Mie, Die Einsteinsche Gravitations Theorie (S. Hirzel,

Leipzig, Germany, 1921).13. G. Mie, "Die g6ttliche Ordnung in der Natur," Das Christliche

Deutschland 1933 bis 1945, Evangelische Reihe: Heft 9(Furche-Verlag/Tibingen-Stuttgart, Germany, 1946), pp. 5-31.

14. G. Mie, Lehrbuch der Elektrizitit und des Magnetismus ( Enke,Stuttgart, 1948).

15. M. Born, "Nonlinear Electrodynamics," Ann. Inst. HenriPoincare 7, 155 (1937).

16. H. Honl, "Intensitats-und Quantitatsgrossen," Phys. Bl. 24,498-502 (1968).

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