The twelfth ordinary general meeting of the South AfricanInstitute of Electrical Engineers was held in the Lecture Theatreof the South African School of Mines, Johannesburg, on Thursday,the 15th December, l'.)l<>, at 8 p.m., Mr. C. W. R. Campbell(President) in the chair.

There were present:—24 members: Messrs. W. Elsdon-Dew,M. Rohmann, F. W. Bentley, W. H. Perrow, G. A. Webb, L. B.Woodworth {Members of Council), J. R. Bradley, H. Collens,A. M. L. Dammrich, F. le Fort, C. C. Fisher, A. E. Gibbs, R. H.Gould, P. Herd, W. H. James, J. W. Kirkland, R. Mortimer, J. E.Maudlen, R. Macgregor, A. B. Nicholetts, H. Newbery, E. H.Owtram, F. F. Parker, S. P. Sather.

25 Associate Members : Messrs. E. D. Brunner, G. W. Lowe,J. S. Ross (Associate Members of Council), J. Birch, W. M. Bow-man, W. E. Bradley, 0. Bjornson, G. H. B. Bernard, T. S. Collins,E. Dalton, J. H. Emms, B. Isaacs, E. Janssen, W. H. Jameson,J. W. Keefe, D. S. Kinsey, H. A. G. Kolb, H. J. Lewis, S. F. May,J. R. Macdonald, A. S. Neilson, F. P. Neve, E. V. Perrow, W.Tobins, T. F. Whimster.

9 Associates and Students: Messrs. P. Fraser Burnett, J. S.Bell, K. W. Carr, E. M. Dahl, P. A. James, W. C. Lindemann,P. Perrow, C. E. Ryder, G. A. de Smidt.

20 Visitors, and Fred Rowland, F.C.I.S., Secretary.

PROCEEDINGS

AT

TWELFTH ORDINARY GENERAL MEETING.

December 15th, 1910.

348Proceedings at Twelfth Ordinary General Meeting.Dec, 1910.

Minutes.

The minutes of the eleventh ordinary general meeting, asprinted in the November Transactions, were confirmed.

Membership.

Messrs. W. Elsdon-Dew and W. H. Perrow were appointedscrutineers, and, after their scrutiny of the b^llot papers, thePresident announced that the candidates for membership andassociate membership had been elected as follows : —

As Members :

Michkli,, Frank Howard, A.M.I.E.E., South African School ofMines and Technology, P.O. Box 1176, Johannesburg. Lecturerin Electrotechnics.

Rider, John Hai.l, M.Inst.C.E., V.P.I.E.E., M.X.Mech.E., M.AmerI.E.E., Messrs. H. Eckstein & Co., Ltd., P.O. Box 149, Johannesburg. Consulting Electrical Engineer.

As an Associate Member :Airman, Andrew Niven, A.M.I.E.E., Victoria Falls and Transvaal

Power Co., Ltd., P.O. Box 103, Oermiston. Assistant to Distribution Superintendent.

The President: In connection with the ballot, it is proposedto send out the ballot papers to members before the meetings, sothat members will be able to place them in a box on entering thetheatre, thus saving the unnecessary delay which the present system involves.

Annual General Mheting.

In connection with the appointment of officers and councilfor the year 1911, members were asked to volunteer their servicesas scrutineers, and the following members came forward, theirappointment being confirmed by the meeting : Messrs. W. Elsdoi^Dew, P. Herd, W. H. James, J. S. Ross, H. (Jollens, A. E. Gibbs,and E. V. Perrow.

On the proposal of Mr. W. H. Perrow, Mr. M. B. Gardner,F.S.A.A., F.C.I.S., was elected the auditor of the Institute'saccounts for the year 1910.

The following paper was then read :—

Frc. 1.Fig. 1 shows how the circuits are arranged in the composite

balance. Coils AA and BB are fixed, AA being wound with finewire, capable of taking a current of one ampere without beingunduly heated, whereas coils BB consist of heavy copper strip,through which currents up to 1,000 amperes may be passed.Coils CC are rigidly connected to a suspended beam, along whichweights may be moved. These coils are wound with wiresimilar to that used for coils AA, and the four are connected inseries for the measurement of cut-rents Tip to 1 ampere. Whenthe current exceeds 1 ampere, coils BB are used, but are not connected in series with coils CC. Through the latter coils a smallmeasured current of a definite value is passed. The coils CC andand the beam are suspended from the fixed rod RR by fine copperligaments. T1 T1 are the fine wire terminals of the instrument andTT are the terminals connected to the heavy coils. One of theterminals T1 may be connected either to W or V The latter connection places all the fine coils in series and is the arrangementadopted in Fig. 2. Connecting to W cuts out the fixed fine coilsas shown in Figs. 3 and 5.

The Kelvin composite balance is essentially a current measuring device, its action depending upon the forces which are set upby currents flowing in neighbouring circuits.

By F. H. MiCHBLL, A.M.I.E.E.

THE MEASUREMENTS OF LARGE ALTERNATINGCURRENT E.M.F.'S AND POWER BY

THE KELVIN BALANCE.

349Dec, 1910. Measurements of Large A. C. E.M.F.'n and Power.

Fi^. 2.X.I.K.—^son-Inductive Resistance.

A standard resistance is connected in series with coils AAand coils CC. When measuring alternating current B.M.F.'s thisresistance must be non-inductive. The current, as measured bythe Kelvin balance, multiplied by the total resistance ofthis circuit, gives the value of the E.M.F. impressed onthe circuit. The current in the above product may not exceed1 ampere, but the resistance may have any value, hence, highE.M.F.'s may be measured if suitable standard resistances areavailable.

If a current C be passed through coils BB and a current cthrough coils CC, then the forces between the two will be proportional to C x c. The standard resistance referred to abovemay be connected in series with coils CC, so .that the current cmay be the result of a high E.M.F., the value of which = C x R,where R i^ the total resistance in the circuit.

Fig. 3 shows the arrangement for the measurement of powerwhen current and E.M.F. emanate from'the same source. If the

The forces set up between the movable and fixed systems areproportional to the products of the currents flowing through thesystems, so that in the case of coils AA and CC being connectedin series the forces are proportional to the squares of the currents.These forces upset the balance of the beam, and in order to bringit to its normal position weights are moved along a shelf attachedto the beam. The operation is, therefore, similar to that ofweighing with a beam balance. When the coils are arranged forthe measurement of a small current the value of the currentflowing is proportional to the square root of the distance throughwhich the weight is moved in order to restore balance. "When acurrent greater than 1 ampere is to be measured, the currentflowing in coils BB is directly proportional to the distancethrough which the weight is moved in order to restore balance,owing to the fact that the current in coils CC is maintained at aconstant value. For the measurement of EMF the apparatus isarranged as shown in Fig. 2.

Measurements of Large A.G. E.j\l,F.'^ and Power. Dec, 1910.550

Fid. 4.

X and Y are two machines, the shafts of which aremechanically coupled. The set is run by a motor or other primemover having a brake power of, say, 6 KW. The machine A iscapable of supplying a current of 1,000 amperes, at at: E.M.F. ofthree volts. The machine B develops an E.M.F. of 1,000 volts, andwill give a current of one ampere. The output of the set is thusfour KW. The 1,000 amperes and 1,000 volts applied to theKelvin balance will, however, indicate an apparent power of-'•—f^j^-— = 1,000 KW. This is only of interest in illustrating the

possibilities of the balance, as there is no necessity to measurepower direct in the continuous current circuit.

The Kelvin balance may, however, be used for the measurement of alternating current E.M.F.'s and power, the inductanceof the fine wire coils of the instrument being rendered negligiblysmall by connecting in series with them sufficiently high standard

non-inductive resistances, so that -rr, reactance over resistance,

3 VOLTSIOOO/1MPS

\poo

There is, however, no reason why the E.M.F. and currentshould emanate from the same source. The E.M.F. = c x Rmay be very high and the current C large, giving an apparentpower of great magnitude, whereas the actual power responsiblefor the E.M.F. and current may be relatively small. Fig. illustrates how such conditions mav obtain.

N.LRFro. 3.

L.—Bank of Lamps.G.—Generator.

supply be continuous current, then the power = C x E and sinceE = c x R, Power = Cc x R. The maximum powerpossible iu such a case is limited by the nature of the supply.

351Dec.. 1910. Measurements of Large A.C. E.M.F.'s raid Power.

Fhi. 5.Tj.—Step-down Transformer.T2.—Step-up Transformer.

Two transformers are necessary, one supplying a largesecondary current and the other a high secondary E.M.F. Figs, tiand 7 are vector diagrams showing the phase relationship betweenthe transformed current and the transformed E.M.F. In eachfigure Vp is the alternator E.M.F. In Fig. (5, Is is the transformedcurrent and in Fig. 7, Es is the secondary E.M.F. of the step uptransformer. This E.M.F. practically coincides with the secondaryterminal E.M.F.

It is seen that the angle between the two may be small, sothat the apparently real power measured by the Kelvin balancemay be only slightly less than the product of the two.

is small. This means that the angle of displacement between theE.M.F. applied to the fine wire circuit, and the consequent currentwhich passes through, the circuit is small. The connections forthe measurement of K.M.F. are as shown in Fig. 2. For themeasurement of power the arrangement is as shown in Fig. 3, thebalance being affected by forces proportional to the product ofthe current c passing through the fine wire coils and thatcomponent of C which is in phase with c, and therefore in phasewith the applied volts. Since this component of C = C X cos.of the angle of phase displacement the mean power measured =c x R x C cos. of the angle of displacement, that is E.M.F. x C xpower factor, which is the true power.

As in the case of the continuous current supply, the currentand E.M.F. may emanate from separate sources, the apparentlyreal power registered by the balance being as before E.M.F. x Cx cos. of angle of displacement between the two. Clearly thearrangement illustrated in Fig. 4 could be applied in this case.

Instead, however, of using rotary apparatus, an arrangementof static transformers will bring about the same conditions. Fig. 5illustrates the scheme.

352Measurements of Large A. C. E.M.F.'s anil Power. Dec, 1910.

There being no discussion offered on papers previously readbefore the Institute, the President drew the attention of members

The President, in referring to the foregoing paper, emphasisedthe utility of the Kelvin Balance in connection with watt-meters,provided either with shunt and series resistances or with currentand potential transformers. He also referred to the point, whichhad only been lightly touched on by the author of the paper,namely, the use of the composite balance in testing A.C. wattmeter equipment ot any power factor. He announced that theauthor would be prepared to exhibit and demonstrate the instrument to the members in the School of Mines Laboratory at afuture meeting.

Fuss. 0 and 7.

The author has carried out a number of experiments with a 5 KW. 180 volt alternator andtwo transformers : the one changed the E.M.F. to2,000 volts and the other delivered from itssecondary a current of 1,000 amperes. TheKelvin balance was effected precisely as explainedabove. A current of 2,000 amperes may be takenfrom the current transformer, but the heavy coilsof the balance are not of sufficiently large cross-section to take such a current. The maximumR.M.S. E.M.F. at the author's disposal is 30,000volts, so that if the necessary standard high tension non-inductive resistances were available, itbecomes patent that the apparently real powerpossible is enormous.

The Kelvin balance is thus an instrument ofgreat possibilities in alternating current circuits,and as it may be moved from place to place andset up almost anywhere, the author thinks thatthere is a sphere for its direct application inpractical engineering, outside the laboratory, incases where accurate measurements of alternatingcurrent power are desired.

Single-phase wattmeters, reading practicallyto any values, may be calibrated by means of thebalance, and such instruments are often used forthe measurement of 3 phase power. Generally,wattmeters are supplied with shunts and series resistances, so thatthe actual instrument may ueal with comparatively small poweronly. In the author's opinion it is, however, much more satisfactory to test instruments and accessories as actually used inpractice, and the scheme outlined in this paper enables this to bedone.

353Dec, 1910. Measurements of Large A.C. E.M.F.'s Mid Power.

The Desi^n ok Misixii Switcikikak.—The rapid increase duringrecent years in the number of collieries equipped with electrical plantunderground, and the consequent increased demand for plant of a specialnature to suit mining conditions, has resulted in there being now upon themarket a very large variety of so-called "mining" switches, motor-starters,&c, and in passing these in review one cannot help thinking that theirdesigners have, in some cases, very little idea of the actual conditions underwhich the results of their labours will be called upon to operate,

In the first place, "mining" switchgear must of necessity mean switchgearsuitable for use in mines, or parts of mines, which are "fiery," that is, inwhich General Rule No. H of the C.M.R.A. applies, and in such mines, it isalmost universally acknowledged that nothing is really safe but switchgearbreaking under oil. This practically disposes of D.C. plant for such minesor situations, and the following remarks apply to A.(\ switchgear only.

Designers of switches for use in mines must bear in mind that such gearwill be in the hands of a different class of operator, to that in control ofwhat might be termed " drawing room switchgear," an operator whose soleobjects in life are (1) to get coal : and ('2) to save himself trouble. Consequently, if he can so overload his haulage motor as to obtain more coal perdiem, without tripping the switch, he will do so. The writer has seen" mining " switches fitted with no-volt and overload releases, which are easilyrendered inoperative by the mere insertion of a piece of wood, say a brokenpick-handle, and no amount of inspection or explanation will ever entirelyremove this danger. Switches must therefore be designed to be "double-foolproof," that is, so arranged that no man, unless provided with tools or aspecial key, can, even deliberately, obtain a shock from them. If not, theswitches should be locked up in a switch room and only operated by theelectrician in charge of the district.

The following points in design should receive particular attention :—A large number of switches are provided with sweating sockets for the

reception of the incoming and outgoing cables, regardless of the fact that asoldering iron is probably out of the question in the position in which theswitch is to work, Mechanical terminals of a substantial nature areinexpensive, and should always be fitted ; they should have ample contactarea for their normal load at a low density, be provided with at least two

ABSTRACTS AND NOTICES

to their failure up to the present to adequately criticise the paperswhich had been delivered, and pointed out that a keener discussion of papers read would have the effect of largely increasing thenumber of papers at the disposal of the Institute.

The meeting then terminated.

354Abstracts and Notices.Dec, 1910.

t)EC, 19lO.Abstracts and Notices.355

screws for clamping the cable, and be so placed in the switchbox that thecable can easily be inserted or removed without dismantling the switch.

The immersion of the switch contacts in oil removes the necessity for aflame-tight case, but the case must still be strong enough to prevent damagethrough accident or careless handling, and should be, as far as possible, dustproof. All joints in the case should be faced metal-to-metal, no packingbeing used.

Fuses in air are out of the question, and in oil they are unreliable—inthe larger sizes at any rate. They should be eliminated entirely, overloador no-volt releases, or both, being provided to suit the conditions. The tripcoils should be oil immersed, as also the resistances in series with the no-voltrelease coil, if these resistances cannot be dispensed with altogether. Triggergear, for the purpose of cutting out Jie trip coils in starting up, is inadvisable,as it may be used, not only at starting, but irregularly as mentioned above.Where it is advisable to cut the trip gear out at starting, this should be doneautomatically in the starting switch.

Ready accessibility of all parts is a most important feature, and theremoval of the oil tank for inspection of the parts usually immersed, shouldbe a one-man job. Many makers seem to have the idea that the smaller theswitch the better ; it is better, however, to sacrifice a little wall or floor space,than to install a switch, the parts of which are so cramped and intermixedthat, in order to find or repair a fault, or to set the trip gear, it is necessaryto take the switch to the surface. The oil tank should be clearly markedwith the correct level of the oil, when removed from the switch, and thislevel should be set to allow a head of oil over the switch contacts when inuse, of at least 1 \ in., to provide for a possible tilting of the switch due tomovement of the floor or wall to which it is fixed. No screws must passthrough the oil tank below the oil level, and all holes for cables enteringthe switch case should be set well above this level, to prevent splashing orcreeping.

If a trifurcating box for the incoming cable can be cheaply included inthe switch case, so much the better. It is not necessary that such a boxshould be arranged to be filled with compound, provided that the cables areso supported inside the box as to guard against their coming in contact with

, any metal. In any case, it is essential that all holes through whichunarmoured cables pass, whether these cables are three-core or single, shouldbe bushed with insulating material, the edges of the bushes being roundedto prevent damage to the dielectric. For armoured cables this bushing is,of course, unnecessary, but an armour clamp must then be provided tosecure continuity of the earthing.

In the case of star-delta or auto-transformer starting switches, the knifeswitch type is preferable to the drum type, as doing away with the gearingnecessary with the latter, if the drum is horizontal: the contacts of a drumtype starter are also very liable to give trouble, and require frequent renewal.If sparking tips are provided, these should be readily renewable.

The switch handle should be of malleable iron or steel, of amplestreugth to withstand the roughest usage, and should have good electricalcontact with the body of the case.

The handle of a starter fitted with an overload release must be " free,"so that the starter cannot be held on against an overload.

An earthing terminal must be fitted in an accessible position on theoutside of the switch case, and it should be capable of taking a j\ cable.

In the case of switches enclosed in a sheet iron unit-type panel, thedetails of the mechanism naturally do not require the same protection as inthe/case of a separate switch, and for this reason particular care should betaken in guarding against the one remaining source of danger—anaccumulation of dust, causing a leakage to earth. These switch panels,particularly when used as feeder panels to a district, cannot be inspectedand cleaned very frequently, and should be made as dust-proof as possible.

To sum up, the order of virtues of a mining switch should be as follows:—1.Safety.—The collier is an inquisitive bird, and will get a shock if he

can.2.Reliability.—The breakdown of one switch may mean the loss of

many tons of coal per day. This annoys the collier—and others. Rememberthat the collier is accustomed to nothing more delicate than a pick and asledge-hammer.

3.Economy.—This does not hurt the collier, and it pleases the others.With the enclosed incandescent lamp fitting as near perfection as it is

to-day, it is strange that the manufacturer has not turned his attention toproviding a more satisfactory lighting switch of small capacity, than is atpresent obtainable—something which will take the place underground of thetumbler switch and fuse. The iron-cased "gas-tight" switches in use aremost unsatisfactory, some of them being actually unsafe, and engineers arecompelled either to adopt a switch of a capacity out of all proportion to theload, or to make up something themselves.

What is wanted is a double-pole, oil-immersed quick-break switch withoil-immersed fuses, or better still, a switch-fuse of about 5 to 10 amperescapacity, the fuses, if separate from the switch, being of the porcelain-bridgetyp^e. Tumbler switches can be used, and would cheapen the article. Theswitch and fuses should be in the same tank, with a division between them,enabling the fuses to be replaced without the danger of touching the liveterminals of the switch. This should make up into a handy and compactlittle switch, and would enable electric lighting to be introduced into almostevery part of a fiery mine with all reasonable safety.—G. M. Harvey, B.Eng.,in The Electrical Review, November 11. 1910, pp. 804-5.

Installation and Opkkation ov Induction Motoks.—The reportmade the following recommendations : (1) That alternating-current motorsmust be provided with no-voltage release devices when such motorswould require a starting mechanism, as several manufacturers are nowfurnishing with their starters ; also that the main-line service for high-tension systems within buildings should be protected by main fuses andautomatic switch. The circuit-breaker should be provided with both overload and no-voltage release. (2) That all alternating-current motors exceptrepulsion-type single-phase and polyphase motors with internal or externalresistance rated at one horse-power or over must be provided with startingand running fuses, the running fuse not to exceed fifty per cent, in size overthe full-load current. (3) That all motors of 7'5 horse-power and over musthave approved starting devices. (4) That polyphase motors requiringrunning fuses are to be wired up to such fuses to carry 250 per cent, of full-load current. (5) That single-phase motors requiring running fuses mustbe wired up to these fuses to carry 225 per cent, of full-load current. (6)That all motors having running fuses must be wired beyond such fuses fornot less than 125 per cent, of full-load current. (7) That all alternatingcurrent motors of a quarter horse-power or over must be operated on aseparate circuit.

Mr. Windsor stated that the most important of several reasons why ano-voltage release is necessary is the fact that unless high-tension installationis prosecuted in that way, the customer has absolutely no hope of saving hismotors in case of a brief interruption on the part of the service.

Mr. Michaelson saw no reason why a no-load release is not needed foran alternating-current motor just as much as a direct-current motor thatneeds a starting device.

The first recommendation was adopted.After some discussion on the second recommendation, Mr. Varnam

moved : " That it is the sense of this Association that two sets of fuseswould be desirable," This motion was carried,

356Abstracts and Notice^.Dec, 1910.

Rendry, H. W. Elementary Telegraphy: A Manual for Students. Or.8vo. pp. 224. Whittuker. Net, 2s. 6d.

Manley, J. J. Observations on the Anomalous Behaviour of DelicateBalances, and an Account of Devices for Increasing Accuracy inWeighings. 4to- Dulau. Net, 2s.

Ellis, A. G. Elementary Principles of Alternating Current Dynamo Design.8vo. pp. 314. Blackie. Net, 12s.

Whittaker, E. T. A History of the Theories of ^Ether and Electricityfrom the Age of Descartes to the close of the Nineteenth Century.8vo. pp. 492. Longmans. Net, 12s. 6d.

NEW BOOKS.

In the third recommendation the horse-power size was changed from7'5 to 5 on an amendment by Emil Anderson.

Mr. Bloomer asked if the members had any trouble in determining whatis considered a fair normal running load. He showed the different practicesadopted by manufacturers in this respect. In some tests at Milwaukee, itwas shown that the power-factor and the efficiency (of some motors undertest) brought the current up to considerably higher than that marked on thename-plate. He thought there ought to be some rule to calculate normalrunning load, or, failing this, the various sizes of wire for the different sizesof machines should be decided upon.

Mr. Tousley cited the Commonwealth Edison Company of Chicago toshow that little or no trouble had been caused, in that company's experience,in burning out of a motor due to overfusing, at least not to warrantadditional expense in the installation of fuses or in the starting apparatus.He went on to say that in his experience the wires are practically overfusedaccording to the Underwriters' Schedule. He allowed 150 per cent, wire,50 per cent, overfusing of that, which gives 225 per cent, of the normalcurrent, and the fuse itself is about 80 per cent, capacity; it allowsconsiderable overfusing of the wires.

Mr. Boyd thought it unwise to permit tbe overfusing of wires. He hadalways required that fuses shall be proportioned to protect the conductor.

Mr. Bennett moved the rejection of the paragraph. The motion wascarried.

The other recommendations met with no opposition and were passed.—From the Report of the Annual Meeting of the Western Association of ElectricalInspectors, Omaha, U.S.A.. October 12, 1910.— Electrical Review and WesternElectrician, October 29, 1910, pp. 883-4.

Earthing Three-phase Networks.—At Frankfort, one of the phasesof the three-phase network has been earthed at the generating stationthrough a water column of 2 ohms resistance, with the result that pressuresurges have been greatly diminished in frequency. The danger of leakage toearth in the network is reduced by one-third, and when a fault occurs on oneof the insulated lines, the circuit-breakers are opened at once. Switches arerequired only on the insulated conductors. In the case of overhead lines,the earthed conductor is carried on the top of the poles, on low-pressureinsulators, and is protected at intervals by low pressure lightning arresters,thus reducing the cost of installation. The results of the system areregarded as very favourable.—The Electrical Review, Nov. 4, 1910, p. 767.

357Abstracts and Notices.—New Books.Dec. 1910.

Provisional applications for Letters Patent will be inserted in this list ascomplete Specifications. Complete Specifications have to be submittedwithin nine months after the provisional application has been supplied, andon the acceptance of the complete Specification, the applicant must advertiseit in three issues of the Gazette. The application and Specification, togetherwith drawings, etc., shall thereupon be open to public inspection. Anyperson may within two months from the date of the latest advertisement, orabout eleven weeks from the date of acceptance, give notice in writing to theRegistrar of Patents of any objection to the granting of such patent.

In the list (P) means Provisional Application ; (C) means CompleteSpecification. The date signifies when filed.

(C.) 410/10. William Arthur Beard. Improvements in and relating torotary engines and the like. 19/8/10.

(C.) 411/10. William Edge. Improvements in hinging machines.19/8/10.

(P.) 412/10. Willie Herbert Stewart. Drill heating and smeltingfurnaces. 19/8/10.

(C.) 413/10. Elizabeth Barnston Parnell. Improvements in thetreatment of ores. 19/8/10.

(P.) 417/10. John Broad Roberts. Anti-phthisical lubricator andappliance. 23/8/10.

(P.) 418/10. Adam Richard Stacpoole (1), Joseph Mahoney (2).Improvements in and appertaining to the shoes and dies of stamp mills.24/8/10.

(C.) 421/10. William Edward Harding (1 , John Hunter (2). Animproved chuck for rock drills and other purposes. 25/8/10.

(P.) 423/10. William Charles Stephens. Improvements in or connectedwith cradles for rock drills and other machines. 25/8/10.

(P.) 424/10. Hans Charles Behr. Improvements in pneumaticpercussive apparatus. 26/8/10.

(C.) 425/10. William David Coolidge. Improvements in tungstenand the manufacture thereof. 26/8/LO.

(C.) 426/10. Emil Deister. Improvements in ore concentrators.o^ /^^/1 n

(P.) 428/10. Cecil Hardwood Fenn (1), David Gavine Hunter (2),John Hathorne Wilson (3). Improvements in rope jockeys. 27/8/10.

(C.) 430/10. Holberry Mensforth. Improvements in internal combustion engines. 29/8/10.

(P.) 431/10. James Auld. Improvements in driving means for theore feeders of stamp mills. 2/9/10.

^C.) 432/10. Robert Emmott. Improvements in crushing, pulverisingand disintegrating machines. 2/9/10,

(P.) 433/10. William Henry Rufus Munnery. An improved double-action stone crusher. 3/9/10. .

(P.) 434/10. Arthur Martin Ludwig Dammrich (1), Charles Hansen(2). Improvements in means for conveying and distributing water orother liquids in mines and the like. 3/9/10.

(P.) 435/10. Arthur Martin Ludwig Dammrich (1), Charles Hansen(2). Improvements in means for conveying and distributing water orother liquids in mines and the like. 3/9/10.

(P.) 436/10. Albert Edward Jordan. Improvements relating tohauling and the like engines^ 3/9/10.

SELECTED PATENT APPLICATIONS.(Transvaal.)

358Selected Patent Applications.Dec, 1910.

*W. ELSDON-DEW, P.O. Box 149, Johannesburg.

M. ROHMANN, P.O. Box 2339, Johannesburg.

^ifcem^evs of Council:

Members:t'T. J. ARMSTRONG.tW. H. PERROW. 7tF. W. BENTLEY.M. SCHWABACH.'

*W. C. BROWN.W. SUTTON. ,fE. CROWTHER.G. A. WEBB

*L. B. W00DW0RTH:

Associate. Mevibevs:E. D. BRUNNER.G. W. LOWE.

*J. S. ROSS.

1bon. ^^reasureu:

T. J. ARMSTRONG, P.O. Box 149, Johannesburg.

•Members of Publications Committee. fMembers of Finance Committee.

Seaetat'g:

FRED. ROWLAND, F.C.I.S.,9, S.A. School of Mines Building, Eloi-^ Street,

P.O. Box 1183. Telephone No. 1404. Tel. Add.: " Scientific."Johannesburg.

iPtesiOent:

C. W. R. CAMPBELL, P.O. Box 217, Germiston.

Officers and Council for the Year endingJanuary, 1911.

The South African Institute

of Electrical Engineers.

(FOUNDED JUNE 1909; INCORPORATED DECEMBER 1909.)