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January 17th, 1894. September 19tli, 1804. 

Fkbrdaby 2l8t, 1894. October 17tli, 1894. 

March 2lBt, 1894. November 2l8t, 1894. 

April 18th, 1894. December :19th, 1894. 

May 15th, 16th, 17tli and 18th, 1S94. 

(Copyright. 1894.) 


At its Office, 26 Cortlandt Street. 



Term eiq^iros 1895. 
DiL N0RV1N GRBEN, 1884-5-6. Prof. EUHU THOMSON, 188990 

FRANKLIN L. POPE. 1886-7. Prof. W. A. ANTHONY, 1S90 91. 

EDWARD WESTON. 1888-9. FRANK J. SPRAOUE. 189d-98. 

Terms expire 1895. Terms expire 1896. 





Terms expire 1895. 


Terms expire 1896. 


Terms expire 1897. 


Terms expire 1895. 


302 Broadway, New York. 26 Cortlandt St. New York. 

Board of Bxaminers : 



StandiDg Committees appoiDted by direetioD of Couneil : 

(^mmlttee on Papers, Meetings, and flkllting. 




Suh- Committee on Editing, Sub-Committee on Papers and Meetings. 




WM. MAVER, Jr., 

litbrary Gonunlttee. 


CommiUee on Flnanoe, Building and Permanent Quarters. 

GEORGE M. PHELPS, Chairman. 




Committee on Units and Standards. 



Committee on Membership etc., 

RALPH W. POPE. Chairman 
THOMAS D. LOCKWOOD, Local Secretary, Boston, Mass.. 
Dr. LOUIS DUNCAN, " " Baltimore, Md., 

CARL HERING, *' ** Philadelphia, Pa., 

Prof. EDWARD L. NICHOLS, " " Ithaca, N. Y., 


BION J. ARNOLD, Local Honorary Secretary. 
574*57^ 1*he Rookery, Chicago 111. Telephone, Main aijg. 



Frontispiece.— Portrait of Frank J, Sprague, Eighth President of the 
Institute.— 1892-83. 

'2. Regular Meeting, January 17, 18d4. Page. 

Practical Properties of Polyphase ^//tfra/«j.— {Illustrated.) By 

Louis Bell, of Chicago. Discussion by William Stanley. O. T. 

7D Crosby, Chas. P. Stemmetz, C. O. Mailloux, Fred'k Darlington, 

M.I.Pupin 1 

Report of Committee on Units and Standards. — Discussion by 
f. Townsend Wolcott, C. O. Mailloux, Chas. P. Steinmetz, A. E. 

Kennelly and C. S. Bradley 48 

Report of Committee on Revision of Rules 52 

,g Regular Meeting, February 21, 1894. 


Forney, Joseph Sachs, E. J. Houston and Almon Robinson ... 50 
Hoiv Shall We Operate an Electric Railway Extending One 
Hundred Miles from the Power Stationf—ilWustT&ted,) By H. 
Ward Leonard, of New York City. Discussion by Chas. G. Curtis, 
C. O. Mailloux, Nelson W. Perry, George Hill. Chas. Hewitt, A. E. 
Kennelly, Wm. Elmer, Jr., C. J. Field. C. J. H. Woodbury, 

Joseph Sachs, R. N. Baylis and Geo. P. Low 76 

Local Meetings at Chicago 108 

Revision of Election Rules 109 

Incompleted Work of the International Electrical Congress of 

iSqs Ill 

Sub-Committees on Incompleted Congress Work 113 

Communication by Theo. J. W. Olan in Discussion of Mr. Mauro's 

Paper 114 

Regular Meeting, March 21. 1894. 

Report of Committee on Units and Standards, — Discussion by A. E. 

Kennelly. Townsend Wolcott, F. B. Crocker, C. S. Bradley. 

Wm. E. Geyer, E. J. Houston, Cary T. Hutchinson, M. I. Pupin 

and F. S. Holmes 124 

On the Effect of Heavy Gases in the Chamber of an Incandescent 

Lamp,—^y Prof. Wm. A. Anthony, of New York. Discussion 
ifi^ by Wm. Lispenard Robb, Elihu Thomson, Edward P. Thompson, 

John W. Howell. W. J. Hammer, Cary T. Hutchinson, S. E. 
BH t>oane, Theo. J. W. Olan, E. A. Colby, L. K. B5hm, Otto A. 
Lia Moses, Wm. A. Anthony, D. McFarlan Moore, R. A. Pessenden 

and Chas. J. Reed 138 

Discussion in Chicago by W. M. Stine, B. J. Arnold, L. Gut- 

mann and Carl Kammeyer 181 


Regular Meeting, April 18, 1894. j i 

Report of Committee on Units and Star dards — Discussion by Towns- 
end Wolcott. E. J. Houston, F. B. Crocker. G. A. Hamilton, W. 
E. Geyer, A. E, Kennelly. Geo. M. Phelps and I. H Famham. . . 188 ^ 

Destructive Effects of Electrical Currents on Subterranean Metal 
Z*^^^.— <Iilustrated.) By Isaiah H. Famham. of Boston, Mass. 
Discussion by Geo. W Plynipton, Townsend Wolcott, A. E. Ken- 
nelly, T. D. Lockwood, I. H. Famham, E. T. Houston, Leonard > i 
Waldo, Chas. E. Emery, Elihu Thomson. Hermann Lemp. Jr. 191 

Discussion at Chicago, April 25. 1894, by B. J. Arnold. A. T. 
Welles, Paul Biefeld, Fred. D. Silber, C. G. Armstrong, A. V. .\ \ 

Abbott 230 

Annual Meeting, Philadelphia, May 15, 1894. 

Report of Council 247 

Secretary s Report 250 

Treasurer's Report . . . 251 

Report of Committee on Units and Standards, — Discussion by Chas. 

Hewitt, C. P. Steinmetz, Fred'k Bedell. A. E. Kennelly, Jas. ' 

Hamblet and Carl Hering 261 

Associate Members Elected and Transferred 261 

Expenses of Chicago Meetings, — Discussion by Chas Hewitt, Geo. 

M. Phelps. Jas. Hamblet. E. J. Houston. W. J. Hammer, R. W. ^ 

Pope, C. P. Steinmetz, A. E. Kennelly and W . A. Anthony. . . 263 

Report of Committee on Revision of ^»/^j.— Discussion by Geo. M. 

Phelps. R. W. Pope, E. J. Houston and F. R. Upton 270 

Teller's Report 273 

A Review of the Progress of the American Institute of Elec 
TR1CAL Engineers. — (Illustrated.) Inaugural Address by Edwin 
J. Houston, President 275 

General Meeting, at Philadelphia, May 16, 17 and 18, 1894, 

On the Subdivision and Distribution of Artificial Sources of IllU' | 

w/«fl//<c?/f— (Illustrated.) By Wm. A. Anthony, of New York. ! 

Discussion by Nelson W. Perry. E. J. Houston A. E. Kennelly, 
C. P. Steinmetz. Clayton W. Pike. R. W. Pope, F. R. Upton, R. 
O. Heinrich and W. J. Hammer 285 

Some Storage Battery Phenomena, — (Illustrated.) By W. W. Gris- 
com, of Philadelphia. Discussion by Louis Duncan, Townsend 
Wolcott. Communications by Sir David Salomons and Fred 1c 
Reckenzaun 802 

Discriminating Lightning Arresters, and Recent Progress in 
Means for Protection against Z/^A/«/>f;f.— (Illustrated.) By 
Alex. Jay Wurts. of Pittsburg. Pa Discussion in Philadel- 
phia by Jos. Sachs, A. J. Wurts, Wm. Stanley, Chas. Hewitt, 
W. E. Harrington. A. E. Kennelly, C. P. Steinmetz and W. J. 

Jenks 837 

Discussion in Chicago, May 23, 1894. by B. J. Arnold. A. V. 
Abbott, L. Gutmann, C. C. Haskins. Geo. M. Mayer. Commun- 
ication by Carl K. MacFadden 896 

Unipolar Dynamos for Electric Light and Power.— iJWyisttBXjeA.) 
By F. B. Crocker and C. H. Parmly. of New York. Discussion 
in Philadelphia by Carl Hering, F. B. Crocker, Wm. Stanley, A. " ' 
E. Kennelly and C. P. Steinmetz 406 

Alternating Currents and Fuses, — (Illustrated.) By D. C. Jackson, 
of Madison, Wis., and R. J. Ochsner. Discussion in Philadel- 
phia by Leonard Waldo and J. P. Jackson. Communication by 
Sir David Salomons 430 

Test of Closed Coil Arc Z^j^^drw^.— (Illustrated.) By R. B. Owens, 
ot Lincoln, Neb., and C. A. Skinner. Discussion by C N. Black 
and C. P. Steinmetz 441 

Relative Advantages of Toothed and Smooth Core Armatures. — 
By Alton D. Adams, of Boston, Mass. Discussion by A. E. Wiener, 

C. P. Steinmetz, Gano S. Dunn, Wm. Stanley, C. N. Black. A. 

E. Kennelly and Oberlin Smith 466 

Standardizing^ Electrical Measuring Instruments. — (Illustrated.) 
By Elmer G. Willyoung, of Philadelphia. Discussion by R. O. 
Heinrich 476 

An optical Phase Indicator and Synchroniser. — (Illustrated.) By 

Geo, S. Moler and Frederick Bedell 502 

A Reliable Method of Recording Variable Current Curves. — (Il- 
lustrated J By Aloert C. Crenore, Hanover, N. H. Discussion 
by C. P. Steinmetz and Wm. A. Anthony 507 

Resonance Analysis of Alternating ana Polyphase Currents. — 
(Illustrated.) By M. I. Pupin, of rCew York City. Discussion by 
W. A. Anthony. C. P. Steinmetz and A. E. Kennelly 528 

Some Facts about Polyphase Motors. — (Illustrated.) By Louis Bell, 

of Chicago Discussion by Carl Hering and C. P. Steinmetz . . . 559 

On the Law of Hysteresis {Part III) ana the Theory of Ferric In- 
ductances.— {\[\M^iT&X.^6..) By Chas. P. Steinmetz, Schenectady, 
N. Y. Discussion by Fred'k Bedell, Chas. P. Steinmetz, M. I. 
Pupin, A. E. Kennelly and W. A. Anthony 570 

Kxpertments on Two- Phase il/^/tfr.y. —(Illustrated.) By Louis Dun- 
can. S. H. Brown, W. P. Anderson and S. Q. Hayes. Discussion 
by Chas P. Steinmetz, C. F. Scott, W. A. Anthony and M. I. 
Pupin 617 

Resolutions Acknowledging Courtesies 687 

Smooth and Toothed Core Armatures.— {Reply to discussion, by A. 

D. Adams, p 465) 637 

Memorial to the United States Congress 689 

Reactance. --^XixMsXxsXe^:) By C. P. Steinmetz and Fred'k Bedell.. . . 640 

Communication by H. J. Ryan 648 

Associate Members Elected and Transferred 650 

Regular Meeting, September 19, 1894. 

A Study of the Residual Charges of Condensers, and their De- 
pendence upon Temperature. — (Illustrated.) By FredTc Bedell 
and Carl Kinsley 656 

TIu Electric Brake in Practice. — (Illustrated ) By Elmer A. Sperrv, 
of Cleveland. Discussion in New York by Jos. Wetzler, C. S. 
Bradley, E. A. Sperry, W. J. Hammer, R. W. Pope, Jos. Sachs, 
Max dsterberg. Robt. McA. Lloyd. Frankland Jannus and E. 
A. Merrill. Communications by B. A Merrill, W. E. Harrington 

and Jos. Sachs 682 

Discussion in Chicago bv Carl Kammeyer. L. H. Rogers. Mr. 
Grier, B. J. Arnold. Edw. Caldwell, W. M. Stine, E. F. Norton 
and Walter Lobach 720 

Regular Meeting, October 17, 1894. 

Theory of Two- and Three -Phase il/^/^r.?.— (Illustrated.) By Lieut. 

Saml Reber. of Fort Riley, Kan. Discussion in New York by 

M. I. Pupin. C. P. Steinmetz and A. E. Kennelly 731 

Discussion in Chicago by W. M. Stine and H. J. Sage 761 

Theory of the Synchronous 2l/i:7/^r.--( Illustrated.) By Chas. P. Stein. 

metz of Schenectady, N. Y, Discussion in New York by A. E. 

Kennelly, M. I. Pupin and Chas. P. Steinmetz 763 

Discussion in Chicago by M. A. Edson 783 

Willy oung on Measuring Instruments.'^Viscussion in Chicago by 

-^ - ^- - -' 788 

uiyoung on Measuring instruments, -^uvsic 
y G. Wray. S. A. Rhodes and W. M. Stine, 




Regular Meeting, November 21, 1894. 

Sugs'estionsfor an Index of Engineering Literature,— ^y Geo. D. 
Shepardson. of Minneapolis. Discussion in New York by T. C. 
Martin, J. Stanford Brown, W. E. Goldsborough (communicated), 
Max Osterberg (communicated). Carl Hering (communicated), 
F. B. Crocker. Edward Caldwell and R. W. Pope. Communi- 
cation by Wm. S Aldrich 789 

Discussion in Chicago by Fred. De Land, W. M. Stine and L. L. 
Summers 821 

Report of Committee on Units and Standards 827 

Regular Meeting, December 19, 1894. 

On the Production of Rotary Magnetic Fields by a Single Alter- 
nating C«rr^«/.— (Illustrated ) )^y Ludwig Gutmann, of Chi- 
cago. Discussion in New York by M. I. Pupin, Townsend Wol- 

cott, A. E. KenneUy and Sam'l Sheldon 832 

Discussion in Chicago by Carl K. MacFadden, L. L. Summers 

L. Gutmann 851 

Communication by Elihu Thomson 853 

Rail Bonding and its Bearing on Electrolytic Corrosion,— (IX- 
lustrated.) Bv Geo. P. Low. A communication in discussion of 
Mr. Pamham^ pajper 867 


Franz Schulze-Berge 873 

Alexander Henry Bauer , . 874 

Rudolf Eickemeyer 876 

Catalogue of Membership, 
Revised to March isty i8gs * 879 

I N D EX. 


Abbott. A. V 242. 896 

Adams. AD 4«5. 687 

Aldrich. W. S 816 

Anderson. W. P 617 

Anthony, Wm. A 132. 183, 174, 177, 268. 285, 292, 294, 295, 296, 

521. 551, 610, 688 

Annstrong, C. G 240 

Arnold, B. J 280. 896, 721, 722. 728, 724 

Baylis.R.N 104 

B«deU, Frederick 258. 502, 609, 611. 614. 640. 656 

Bell. Louis 8. 32, 42, 46, 659 

Biefeld, Paul 236 

Binney. Harold 657 

Black. C.N 460, 468, 464, 474 

Bdhm. L. K 168 

Bradley, C.S 62. 128, 129, 710, 7J3. 716 

Brown, J. Stanford 796 

Brown. S. H 617 

Burnett. Douglas 108, 110 

Caldwell, Edward 728, 724, »»8 

Colby.E.A 165 

Crehore. A. C 507 

Crocker, F. B 126. 130, 189. 190, 260, 261, 406, 424, 429, 655, 681, 

710, 717, 801, 808 

Crosby. O. T 89 

Curtis, C.G 84. 85, 86, 87, 88, 92, 98, 94, 95 

Darlington, F 48, 44, 45 

De Land. Fred 821 

Doane, S. E 162 

Duncan, Louis 320, 617 

Dunn. G. S 472. 478 

Edson. M. A 788 

Elmer. Wm., Jr 100 

Emery. C. E 226 

Famham. I. H 190, 191. 220, 222, 224, 244 

Fessenden. R. A 178 

Field. C.J 101 

Fomey.M.N 72 

Gteyer.Wm. E 128, 131, 189 

Goldsborough .W.E 798 

Grier. Mr 720. 722, 728, 724, 725, 726 

Griscom. W. W 802. 321, 823, 380 

Gutmann. L 398, 882, 852, 868, 854 

Hamblet , James 259, 264, 267 


Hamilton, George A 189 

Hammer. W.J 161, 162, 364, 265. 270, 300, 558. 711 

Harrington, W. E 718 

Haskins. C. C 401 

Hayes. S. 6 617 

Hemrich. R . O 296. 402 

Hering.Carl 261. 268, 423. 569, 800 

Hewitt, Charles 96, 98, 100, 257, 261, 263, 264, 381, 382, 883 

Hill. George 95, 98 

Holmes.F.S 132 

Houston, E. J ...32, 43, 49, 52, 54. 55. 72, 73, 75, 102, 104, 105, 107. 
108. 109, 110, 125, 129. 132. 150. 151, 161, 162, 176, 
188, 189, 190, 214, 223, 246. 251. 257, 259, 260. 261, 
263. 264. 268, 269. 270. 271, 272. 274, 275, 292, 295, 
296, 800, 301. 429, 464, 551, 557, 558. 569, 637, 796, 

812, 831, 848, 851 

Howell. J. W 156, 175 

Hutchinson, Gary T 129, 130, 132, 161 

ackson, D. C 184, 430 

Jackson, J. P 440 

Jannus.F 714, 715 

enks, W.J 392 

'Cammeyer. C 720, 721, 723 

Kennelly, A. E 50, 55. 98, 125, 126, 130, 132. 174. 189, 216, 258, 

260, 268, 292, 383, 387, 393, 425, 474, 555, 610, 

760. 777, 850 

Kinsley, Carl 656 

Lemp, H. 228 

Leonard. H. Ward. .75. 76. 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 

97. 98. 100, 105, 108 

Lloyd, R. McA 713 

Lobach, W 726 

Lockwood, T. D 221 

Low, G. P lu7. 857 

MacFadden. C K 404, 851, 852 

Mailloux. C. 43. 49, 51, 52. 88. 99, UK) 

Martin. T.C 796, 803 

Mauro, P 55, 56. 114 

Mayer, G. M 402 

Merrill, E. A .715, 716, 717 

Moler. G. S 502 

Moore, D. McF 177 

Moses, O. A 170 

Norton, E. F 726 

Ochsner, R. J 43o 

Olan, T. J. W 71. 114. 163, 170 

Osterberg, M 712, 799 

Owens. K. B 441 

Parks. C.W 818 

Parmly.C.H 406 

Perry, N. W 89, 91. 92. 292 

Plympton, G. W 214. 222 

Phelps. G. M 108, 109, 110, 189. 260, 263, 264, 265, 267. 269, 270, 271 

Pike, C . W 293 

Pope, R. W 52, 109, 110, 188, 261, 266, 271. 295, 711, 8('9 

Pupin, M. I.... 46, 130, 151, 523, 555. 557, 611, 614, 636, 748, 753. 754. 

779, 781, 782, 846, 849. 850 

Reber, Samuel 731 

Reckenzaun, F 325 

Reed. C.J 179 

Rhodes, S. A 784 

Robb, W. L 150 

Robinson, Almon 74 

Rodman, S 783 


Rogers, L.H 720, 721. 722, 728, 724, 725, 726, 727 

Ryan, H J 648 

Sachs, J 78, 108, 378, 879, 888, 712. 714, 716, 717, 719 

Sage. H.J 761 

Salomons, Sir D 824,440 

Scott, C. F 632, 638 

Sheldon, S 850 

Shepardson, G. D 789 

Silber, F. D 286 

Skinner. C. A .441 

Smith. Oberlin 474 

Sperry. E. A 681, 682, 710. 711, 712, 718, 714. 715, 716, 717, 718. 720 

Stanley. W 82, 43, 879, 880, 425, 478 

Steinmetz, C. P. . . . 40, 45. 43, 47, 49, 257, 259, 260. 268, 293, 387, 395, 
426, 460, 468, 464, 470. 473, 474. 521, 551, 557, 569, 
570, 609, 610, 611, 212, 614, 632, 685, 640, 751, 758, 

754, 763, 781, 782 

Stewart, Mayor of Philadelphia 246 

Stine. W. M 181, 236. 720, 721, 724, 726, 727, 728, 761, 784, 822 

Summers, L. L 821. 825, 851, 852, 853 

Thompson, E. P 70,154 

Thomson, Elihu 151, 227, 858 

Traut^^nne, J. C, Jr 246 

Upton, F. R 108, 272, 295 

Vansize.W.B 68 

Waldo, Leonard 226, 489 

Welles, A. T 234. 286 

Wetzler,J 710 

Wiener. A. E 469 

Willyoung. E. G 476 

Wolcott.T 49, 125, 128, 188, 216, 322. 849. 850 

Woodbury. C. J. H 102 

Wray.J.G 783 

Wurts. A.J 887. 878, 879. 880, 381. 382, 388. 386, 387, 892, 894 


Administration of the Patent Office. Concerning a Change of Policy in 

ihe (Pktltp Mauro) 56. 114 

A. I. E. E., Review of the Progress of the (Inaugural Address, Presi- 
dent Houston) 275 

Alternating and Polyphase Currents, Resonance Analysis of {M. I. 

Pupit^ 528 

Alternating Current. On the Production of Rotary Magnetic Fields by a 

Smz\e {L, Gutmann) 882 

Altematmg Currents and Fuses (D. C. Jackson and R. J. Ochsnef) . . .480 

Apparatus, Practical Properties of Polyphase {Louis Bell) 8 

Arc Dynamo, Test of a Closed Coil {R, B, Owens and C A. Skinner). .441 
Artificial Sources of Illumination, On the Subdivision and Distribution 
oiiW. A. Anthony) 285 

Balance Sheet, Secretary's 250 

Bauer, Alexander Henry (Obituary) 874 

Brake in Practice, The Electric {Elmer A, Sperry) 682 

Building Fund x;51 

Catalogue of Members 879 

Change of Policy in the Administration of the Patent Office, Concern. 

ingSiiPkiltp Mauro) 56, 114 

Chicago, Local Meetings at 107, 268 

Closed Coil Arc Dynamo. Test of a (H. B. Owens and C A. Sktnmr) .441 

Committee on Installations, Report of 55B 

Committee on Resolutions 687 

Committee on Revision of Rules, Report of 52, 270 

Committee on Units and Standards, Report of 48. 124. 188. 252. 827 

Concerning a Change of Policy in the Administration of the Patent 

Omce {Philip Mauro) 66. 114 

Condensers and their Dependence upon Temperature. A Study of the 

Residual Charges of (Frederick Bedell and Carl Kinsley) 656 

Congress, Memorial to. Prepared and Submitted by the Committee on 

Units and Standards 689 

Congress of 1893. Incompleted Work of the International Electrical 111 

Council, Report of the 247 

Current Curves, A Reliable Method of Recording Variable {A. C. Cre- 

hore) 507 

Destructive Effects of Electrical Currents on Subterranean Metal Pipes 
(/. H, Farnham) 191, 857 

Discriminating Lightning Arresters, and Recent Progress in Means for 
Protection Against Lightning {A. /. Wurts) 387 

Dynamo. Test of Closed Coil Arc {R, B. Owens and C. A, Skinner). . . .441 

Dynamos, Unipolar {F, B. Crocker and C. H. Parmly) 406 

Effect of Electrical Currents on Subterranean Metal Pipes, Destructive 

(/. H. Farnham) 191, 857 

Effect of Heavy Gases in the Chamber of an Incandescent Lamp. On 

theiPV. A. A nihony) 183 

Eickemeyer, Rudolf (Obituary) 876 

Election of Officers, Vote for 278 

Electrical Congress of 1893. Incompleted Work of the International HI 

Electrical Currents on Subterranean Metal Pipes, Destructive Effects of 

{I. H. Farnham) 191,857 

Electrical Measuring Instruments, Standardizing (E. G. Willyoung) 476, 783 

Electric Brake in Practice, The (E. A. Sperry) 682 

Electric Railway Extending One Hundred Miles from the Power Sta- 
tion, How Shall We Operate an {H. Ward Leonard) 76 

Electrolytic Corrosion. Rail Bonding and its Bearing on {Geo. P. Low),J&5>7 
Engineering Literature. Suggestions for an Index of (^^^. D. Shepard- 

son) 789 

Experiments on Two-Phase Motors {L. Duncan, S, H. Brown ^ JV, P, 

Anderson and 5 Q, Hayes) 617 

Expenses of Local Meetings at Chicago 268 

Expenses of the Institute, Itemized Statement of Receipts and 250 

Ferric Inductances, On the Law of Hysteresis (III.) and the Theory of 

{€. P. Steinmetz) 570 

Fund. Building 251 

Fuses, Alternating Currents and (/?. C. Jackson and R. /. Ochsner).. . .480 

Heavy Gases in the Chamber of an Incandescent Lamp, On the Effect 
of ( JV. A. Anthony) : 183 

How Shall We Operate an Electric Railway Extending One Hundred 
Miles from the Power Station ? {H, Ward Leonard ) 76 

Hysteresis (Part III.) and the Theory of Ferric Inductances, On the 
Law of (C. P. Steinmetz) 570 

Incandescent Lamps. On the Effect of Heavy Gases in the Chamber of 

^n\W. A, Anthony) 188 

Incompleted Work of the International Electrical Congress of 1893 Ill 

Index of Engineering Literature, Suggestions for an (5^^. D. Shepard- 

son) 789 

Instruments, Standardizing, Electrical Measuring (^. G. Willy oung)A^^^ 788 
Itemized Statement of Receipts and Expenditures of the Institute 250 


Lightning Arresters. Discriminating (A. J. IVurts) 837 

Literature, Suggestions for an Index of Engineering {Geo. D. Skepard- 

son) 789 

Local Meetings at Chicago 107, 868 

Memorial to the United States Congress, Prepared and Submitted by 

the Committee on Units and Standards 689 

Motors, Experiments on Two-Phase (Z. Duncan, S, H. Brown, W, P. 

Anderson and S. Q. Hayes) 617 

Motors, Some Facts about Polyphase (Louis Bell) 569 

Motors, Theory of Two- and Three-Phase {Samuel Reber) 781 

Motor, Theory of the Synchronous (C P, Steinmetz) 768 

Obituary : Franz Schulae-Berge 878 

Alexander Henry Bauer 874 

Rudolf Eickemeyer 876 

One Hundred Miles from the Power Station, How Shall We Operate an 

Electric Railway Extending {H. Ward Leonard) 76 

Optical Phase Indicator and Synchronizer, An {Geo. 5. Moler and 
Frederick Bedell) 502 

Patent Office ; Concerning a Change of Policy in the Administration of 

th^ {Philip Mauro) 66.114 

Phase Indicator and Synchronizer, An Optical {Geo. S. Moler and 

Frederick Bedell ) 609 

Polyphase Apparatus, Practical Properties of {Louis Bell) 8 

Polyphase Currents, Resonance Analysis of Alternating and (J/. /. 

Pupin) 628 

Polyphase Motors. Some Pacts about {Lcuis Bell) 669 

Practical Properties of Polyphase Apparatus {Louis Bell) 8 

Rail Bonding, and its Bearing on Electroljrtic Corrosion {Geo. P, Z^te/). .857 

Reactance {C. P, Steinmetz and Frederick Bedell) 640 

Receipts and Expenses of the Institute, Itemized Statement 260 

Recent Progress in Means for Protection Against Lightning {A. J. 

IVurts) 887 

Recording Variable Current Curves, A Reliable Method of {A. C Ore- 

hore) 607 

Relative Advantages of Toothed and Smooth Core Armatures {Alton 

D.Adams) 465, 687 

Report of Committee on Installations 568 

Report of Committee on Revision of Rules 58, 270 

Report of Committee on Units and Standards 48, 124, 188, 262, 827 

Report of the Council 247 

Report, Teller's 278 

Report. Treasurer's 261 

Residual Charges of Condensers and their Dependence upon Tempera- 
ture. A Study of the {^Frederick Bedell and Carl Kinsley) 656 

Resolutions Acknowledging Courtesies 687 

Resonance Analysis of AJternating and Polyphase Currents {M. L 

Pupin) 628 

Review of the Progress of the American Institute of Electrical Engin- 
eers {President Houston). Inaugural Address 275 

Revision of Election Rule :.62. 108, 270 

Revision of Rules, Report of Committee on 62, 270 

Rotary Magnetic Fields by a Single Alternating Current, On the Pro- 
duction of {L. Gutmann) 882 

Schulze-Berre, Franz, Obituary , 878 

Secretary's Balance Sheet 260 

Single Alternating Current, On the Production of Rotary Magnetic 

Fields by a {L. Gutmann) 882 

Smooth Core Armatures, Relative Advantages of Toothed and {Alton 

D.Adams) 465, 687 

Some Facts about Polyphase Motors (Louis Bell) 65^ 

Some Storage Battery Fhenomena ( IV . IV. Griscom) 802 

Standardizing Electncal Measuring • Ins tniments(£\ G. IViilyoung)^!^^ 788 

Statement of Receipts and Expenses of the Institute, Itemized 250 

Storage Battery Phenomena, Some ( IV. W. Griscom) 802 

Sub-Committees on Incompleted Congress Work 118 

Subdivision and Distribution of Artificial Sources of Illumination, On 

\\l^{W. A. Anthony) 285 

Subterranean Metal Pipes, Destructive Effect of Electric Currents on 

{I. H, Farnham) 191, 857 

Synchronous Motor, Theory of the (C P, Steinmetz) 768 

Teller's Report 273 

Test of a Closed Coil Arc Dynamo (R. B. Owens and C. A. Skinner). . 441 

Theory of the Synchronous Motor (C. P. Steinmetz) 768 

Theory of Two- and Three-Phase Motors (5. Reber) 731 

Toothed and Smooth Core Armatures, Relative Advantages of (Alton 

D. Adams) 465, 687 

Treasurer's Report 251 

Two- and Three-Phase Motors, Theory of (S. Reber) 781 

Two-Phase Motors, Experiments on (L. Duncan, S. H. Brown, W. P. 

Anderson and S. Q. Hayes) 617 

Unipolar Dynamos for Electric Light and Power (F. B. Crocker and C, 

H. Parmly) 406 

Units and Standards, Report of Committee on 48, 124, 188, 252, 827 

Vote at Annual Election 273 


The Institute as a body is not responsible either for the state- 
ments made, or for the opinions expressed, in the following 

McIlroy ft Emmbt, Steam Printen, 36 Cortlandt St., New York. 




Vol. XI January to December, 1894. 

New York, January 17, 1 894. 

The 83d meeting of the Institute was held this date at 12 West 
31st Street, and was called to order at 8 p.m. by President 

The President: — ^The Secretary will read the minutes of th# 
last stated meeting. 

On motion of Mr. Wolcott it was voted that the reading of 
the minutes be dispensed with. 

The President : — Before calling for the paper of the evening, 
I would like to ask the Secretary to read the list of candidates 
for associate membership, and the names of members who were 
either elected at the Council meeting to-day, or transferred from 
associate to full membership. 

The Secretary: — The following candidates for associate 
membership have been proposed for consideration at the meeting 
of the Council, Feb. 21st:— 

H H. Morehouse, James W. Crosby, E. Randolph Hix, Edward M. Gerry, 
E. W. Trafford, George E. Wendle, Charles Gesseaume, Charles T. Rittenhouse, 
Arthur Frantzen, Albert E. Richardson, S. D. Snook, Jas. A. Lighthipe, Albert L. 
Clough, A. T. Best, Harold Harrison, Clifford D. Babcock, Augustus Treadwell, 
Jr., Wm S. Barstow, Chas. Edwin Potts, George Forbes. 

The following associate members were elected at the Council 
meeting this afternoon: 

Name. Address. Endorsed by. 

Adams, Comfort A., Jr., Instructor in Electrical Engineer- E. H. Hall. 

ing. Harvard University, 2i C.F. Uebelacker, 

Stoughton Hall, Canibridge, Mass. E. P. Roberts. 

Bkthell, U. N. Acting General Manager, The Met- A. E. Kennelly. 

ropolitan Telephone & Telegraph H. L. Webb. 

Co., iS Cortlandt St., N.Y. City Geo. M. Phelps. 

Broadnox, Francis Engineer, Safety Insulated !Wire W. J. Jenks. 

and Cable Co., 50 Broadway, L. Stieringer. 

New York City. T. C. Martin. 

Broich, Joseph Superintendent and Electrician, Edw. Durant. 

with F. Pearce, 448 8th Ave., James Hamblet. 

Brooklyn, N.Y. J. C. Chamberlain. 


Ends, Sigfried H. 

Colonnade Hotel, 39 Layfayette C F. Chandler. 
Place, New York City. Wm. J. Hammer. 

F. B. Crocker. 

Flanagan, Thomas Francis Supt. and Electrician, Herbert C. Wirt. 

Portsmouth Gas Light Co , C. D. Haskins. 

Portsmouth, N. H. C. B. Burleigh. 

Flint, Bertram P. Electrical and Mechanical Engineer, Chas. H. Davis. 

with Chas. H. Davis, 120 Broad- F. S. Holmes. 

way, New York City. Ralph W. Pope. 

Knox, James Mason Student in Electrical Engineering, F. B. Crocker. 

Columbia College, School of Ralph W. Pope. 

Mines, New York City. W. H. Freedman. 

Asst. Superintendent Operating, L. S. Boggs. 

Electrical Dept. Midwinter R. H. Pierce. 

Fair, San Francisco, Cal. G. Sacco Albanese. 

Student in Electrical Engineering, F. B. Crocker. 

Columbia College, 232 East 62nd M. I. Pupin. 

St.. New York City. W. H Freedman. 

Deep River, Conn. Ralph W. Pope. 

T. C. Martin. 

Geo. H. Guy. 

M. I. Pupin 

F. B. Crocker 

W. H. Freedman 

A. F. McKissick. 

A. M. Schoen. 

A. E. Worswick, 

L. S. Boggs. 

R. H Pierce. 

O. G. Dodge. 

Edw. L. Nichols. 

F. Bedell. 

Harris J. Ryan. 

Meredith, Wynn 

Osteeberg, Max 

Selden, R. L., Jr. 

Sever, George F. 

Smith, Charles Henry, 

Sprout, Sidney 

Wardlaw, George A. 

Instructor in Electrical Engineer- 
ing, Columbia College. 121 East 
30th St., New York City. 

Assistant Electrician, South East- 
em Tariff Association, Atlanta, 

Electrical Department, Midwinter 
Fair, San Francisco. Cal. 

Assistant Engineer, People's Light 
and Power Co. , Doolittle House, 
Oswego, N. Y. 

Total 15 

The following associate members were transferred to full 
membership upon recommendation of the Board of Examiners, 
October 3d and December 7th, 1893 

Emmet, W. L, R. 

Keith, Nathaniel S. 
Adams, Alton D. 

McCluer, C. E. 

Jackson, J. P. 

Total 5. 

Electrical Engineer, General Electric Co., New York 


Electrical Engineer, London, Eng. 
Electrician and Manager, Adams] Electric Co., 

Worcester, Mass. 
Supt. First District, Southern Bell Telephone and 

Telegraph Co., Richmond, Va. 
Assistant Professor of Electrical Engineering, Penn. 

State College, State College, Pa. 

Th» PEKsroBNT : — The regular order of business is the paper for 
the evening. We are very fortunate this evening iu having with 
us a gentleman who is in every respect able to handle the im- 
portant subject on which he is announced to speak, viz.: " Prac- 
tical Properties of Polyphase Apparatus." Dr. Louis Bell, of 
lioston, will now read the paper. 

De. Bbll read the following paper : 

A faptr presented at the Etghiy-tkird Meeting of 
the American Institute of Electrical Engi- 
neered New Yorky January ifthy 181)4.^ President 
Houston in the Chair. 



During the past two years the use of polyphase currents for 
power transmission has been the subject of many papers and 
discussions. The writers engaged have been of two classes, 
those who have a practical concrete knowledge of the apparatus 
they comment upon, and those who have not. The former have 
for the most part merely interpolated casual remarks and made 
general recommendations. The latter have been prolific in re- 
searches upon paper, and experiments upon the electrical bric-a- 
brac they could build or borrow. The whole matter has been 
for the most part a sort of '' Messiah dance " of doctrinaires^ 
varied now and then by a skirmish between rival inventors who 
for commercial reasons could give the public very little detailed 
information. Meanwhile the art has been quietly advancing, 
and to-day, with half-a-dozen plants in operation abroad, 
and as many more in our own country, it is time to discuss 
more freely than has hitherto been possible, their nature and 

In the present paper I intend to devote myself entirely to ex- 
))erimental results, verified by repeated observation, and leave 
the mathematical investigation of the subject to those who pre- 
fer to conceal their more or less exact knowledge in that alluring 
guise. I have no lack of respect for mathematics, but it offers 
a painfully good opportunity for generalizations so broad as to be 
of no practical use. 

In speaking of polyphase apparatus it should be clearly under- 
stood that I regard the number of phases as accidence rather 


than as substance of the matter. As the namber of phases is 
changed, the quite interesting and not always unimportant differ- 
ences to be noted are more often of degree than of kind, so that 
while most of ray personal experience has been with triphase 
currents, much of what I have to say is quite applicable to sys- 
tems having more or less phases, provided, of course, that such 
systems are symmetrical. 

Of systems wherein this condition is not fulfilled I shall have 
something to say in discussing polyphase motors. I also pre-sup- 
pose that we are to deal with currents giving a tolerable approxi- 
mation to sine waves, such as can without great diflSculty be ob- 
tained. While it is theoretically true that departure from the 
sine curve causes a loss of energy due to the presence of higher 
harmonics, they must be larger than are found in any well 
designed machine before they produce any loss of efficiency that 
is of practical consequence. I have observed a measurable de- 
crease of eflSciency in an induction motor when used with a 
generator arranged to give a very wide departure from a sine 
wave, but even so, less than might easily be due to accidenta 
variations in the iron used for the laminated structure. Electri- 
cal power transmission must be developed into conditions beyond 
those that now seem to us extreme, before the current curves now 
readily attainable will need revision. On very long lines and 
under voltages already near the limit of insulation, we shall 
certainly have to consider the matter, but in the present state of 
the art we may generally pass it by. I shall refer later to cases 
in which it is really of decided importance. 

Polyphase Generators. 

While the general character of polyphase dynamos must 
closely resemble that of the ordinary alternator, the necessity of 
applying to the same armature two or more phase-windings leads 
to modification of the design so far as the winding is concerned, 
and quite generally in the direction of the direct current type. 
In fact the most convenient way of getting polyphase currents 
in the laboratory or for experimental use, is to tap the head of a 
continuous current armature in the requisite number of points, 
put on collecting rings and go ahead. A small multipolar ma- 
chine of 220 or 500 volts lends itself most readily to this use, 
but generally will have to be run at a speed considerably higher 
than normal to give a suflScient number of cycles. The current 


wave given is apt to be flat-topped, and in small machines the 
windings cannot always be tapped symmetrically, but the method 
is often handy. It may sometimes be useful too, to derive poly- 
phase currents from two or more ordinary alternators with their 
shafts coupled together, or from composite machines having 
phases on separature armature cores, but these devices are, I 
think, rather to be regarded as expedients convenient for divers 
reasons than as final types. This is on the broad general prin- 
ciple that one large machine is more economical than two or 
more small ones aggregating the same output, and that the more 
completely the armature core can be utilized, the better output 
can be obtained from the same structure. Therefore with similar 
machines of equal size and equal magnetic and electrical con- 
stants, a polyphase armature winding does give a better output 
than a single phase winding. Of course it is possible to con- 
struct a single phase machine that shall give a better output per 
pound of weight than a certain concrete polyphase machine, 
just as one might manage to double the voltage obtained from a 
given armature while retaining the same output, but other things 
being equal the more phases, the better output in a given struc- 
ture. All this has been made so clear of late that it is only 
necessary to emphasize the fact, that while the difference in out- 
put between a single phase and a two-phase armature is quite 
considerable, the step from two, to three phases is somewhat 
less marked, and that from three to more, of relatively little 

It should also be noted that as various numbers of phases can 
be derived quite simply from two and three phases, it is quite 
unnecessary to consider the more complicated types of generator. 
The tendency in building polyphase generators is certainly to- 
ward the development of a rather better machine than we have 
become familiar with in the ordinary alternators, due mostly to 
the impetus given alternating current machinery in general by 
recent demands. This has led, first, to the adoption of a lower 
frequency than formerly, both to facilitate the use of motors and 
to avoid the serious difiiculties due to inductance on the long 
lines that are now becoming more common. Second, it has 
caused more attention to be given to the production of genera- 
tors able to take care of fluctuating and inductive loads, such as 
are produced by motors, without excessive over-compounding. 
With a properly designed machine, the popular idea of the diffi- 


calty of regulation under an inductiv^e load is grossly exagge- 
rated. A generator built as alternating generators should have 
been built long before now, with proper attention to the produc- 
tion of a good machine for all around practical work, will take 
care of an inductive load of the severest kind, more easily than 
the average alternator found to-day in central stations, will handle 
a load of incandescent lights. 

I can point out the practical ease of regulating a polyphase 
generator under an inductive load in no way so effectively as by 
giving the results of some experiments recently tried with a tri- 
phase generator of 260 k. w. normal output. It was ran at 600 
revolutions per minute, and a uniform voltage of 25(»0 volts be- 
tween lines, driving a synchronous motor of similar size, which 
was in turn belted to a direct current generator. This arrange- 
ment enables one to obtain any desired output with a very wide 
range in the lag of the current through the line. Accurate read- 
ings were taken of the currents necessary to excite the generator, 
with the following results, the voltage being preserved uniform 
at 2500 : 

Exciting current- output about 80 k. w. No lag 19.05 amp. 

Exciting current-output about 80 k w. Power Factor .2 21 .5 amp 

Exciting current- output 260 k. w. No lag 22.8 amp. 

Exciting current-output 260 k. w. Power Factor .84 24.8 amp 

No better test than this could be wished, for showing the exci- 
tation required under a lagging load. It should be noted that the 
power factor in the last case was similar to what would be found 
under ordinary circumstances, in running a load of inductive 
motors, and yet the increase in exciting current from a very 
light load with no lag, to a full load with very decided lag, was 
only 25 per cent Experiments with other machines under an 
inductive load show results similar to this, so that I think we can 
safely say that a well-designed polyphase generator will take 
care of an inductive load easily and without excessive variation 
of the field strength. More than this, the regulation required 
can easily be made automatic in cases where this method is pre- 
ferred to hand regulation, which, however, answers most pur- 
poses very well. 

Of course the polyphase generator can be made self -com pound- 
ing in a manner closely analogous to that followed with an ordi- 
nary alternating generator. The rectification of the necessary 
amount of current, makes this method somewhat inconvenient m 



large machines. In snch cases, we may effect a very complete 
automatic regulation by the following means. 

[Diagram of the apparatus is shown in Figure 1.] 
The generator is excited from a rotary converter taking its 
polyphase current from the main machine of which it feeds the 
:field magnets through its direct current side. In the lines be- 
tween the rotary converter and the generator, are inserted induc- 
tive resistances which serve to cut down the voltage applied to the 
polyphase end of the rotary converter. On these choking coils 
are, however, reversely wound turns from the main circuit of 
the machine. The result of this arrangement is, that as the cur- 
rent in the main line fed by the generator rises, the inductance 
in the line which feeds the rotary converter is gradually removed, 

Fig. 1. 

aJlowing the voltage to rise higher and higher, in proportion to 
the current in the main line. 

Fig. 1 gives a clear idea of the arrangement. In this figure, 
a' is the field magnet of the main machine of which b is the 
armature, a the three collector rings, the machine being of triphase 
type ; f f are the field magnets of the rotary converter of which d is 
the armature, 1) the collector rings and s a commutator delivering- 
direct current to the fields of the rotary converter f f and to the 
field magnets a' a' of the generator. The rotary converter may 
conveniently be brought up to speed by its pulley p unless an- 
other triphase machine be at hand by which to start it ; m, m', 
vf are the three inductive resistances, e the windings connected 
with the rings J, d the reversely wound turns connected to the 


main line. Of course transformers may be inserted in the line 
between the inductances and the rotary converter, if the volt- 
age of the main generator renders it desirable. In fact such 
converters wound with cumulative turns from the main circuit 
may replace inductive resistances. I have experimented, rather, 
more, however, with the form shown in Fig. 1. It may some- 
times be convenient to employ the rotary converter merely to 
excite an auxiliary compound winding, in which case it can be 
started up from the generator already worked up nearly to nor- 
mal voltage by its own exciter. This method of compounding 
polyphase generators, seems to promise ready applicability to the 
largest machines and very close automatic regulation of the 
voltage. The arrangement may be varied, but the underly- 
ing principle must remain the same — the automatic variation 
of voltage on the polyphase end of a rotary converter, in re- 
sponse to the varying output of the generator by means of vary- 
ing inductances obtained from coils in the main circuit, and act- 
ing either directly or reversely to govern voltage applied to the 
rotary converter. In practice, the method works quite satisfac- 
torily and effecti7ely. It permits of very close regulation of the 
voltage for all loads at the machine, or of over-compounding at 
the distant end of the line and that even with severely inductive 
loads. I have tried a number of experiments to determine the best 
working conditions of this method of compounding, and the re- 
sults are most striking. 

A certain experimental generator of about 30 k.w. capacity, 
provided with triphase armature was fitted with this method of 
regulation, employing for the rotary converter a small 4-pole 
iron-clad machine fitted with triphase connections. The speed 
of the generator was kept constant at 600, the rotary converter 
running at 1500 ; at no load, the voltage was 119; at full load 120, 
the load consisting of banks of incandescent lamps operated on 
the secondaries of converters. In another experiment with the 
same machine at the same initial voltage, an over-compounding of 
10 volts was easily obtained. Without regulation, the generator 
had so high an armature reaction that it would not regulate 
within forty per cent. On a standard triphase generator, very 
close automatic regulation can be obtained by this method, while 
even with the experimental machine just mentioned above, it is 
possible to reach quite satisfactory results. 



I have a record of experiments made after this paper was 
written, and illustrated in Fig. 2. The generator was first run 
with a non-inductive load at 114 volts initial. The output was 
driven up to 20^ kilowatts and the voltage at the end was 116.0 
(a). It had varied slightly in the earlier portion of the curve, 
the extreme variation from the initial voltage being a couple of 
volte. That was with a poor machine, and lacked the good re- 
sults that could have been obtained had the compounding ar- 
rangement had less work to do. We then tried the same machine 
under inductive load (b). The initial voltage was again 114 and 
it was arranged to over-compound so that at 30 k. w. we got 148 
volts. The device over-compounds just as handily as it com- 
pounds for uniform voltage, and furthermore I may say that by 
proper adjustment of the inductive coils and the rotary con- 

















3. 2. 






verter, it is possible to make the machine compound closely or 
over-compound, either for inductive load or non-inductive load, 
or for a load which is varying, sometimes non-inductive and 
sometimes inductive. The very act of the shifting of the phase 
due to nmning with an inductive load, may be made to help the 
rotary converter overcome the lagging current, as was the case 
in the example 1 have just given, where the voltage rose some- 
thing like 25 volts on a heavy load consisting of induction 
motors running very light. 

All this matter of regulation, is of particular moment in 
installations intended mainly for power purposes where the 
variations in load are apt to be considerable. Where, however, 
these variations are extreme I do not believe that any automatic 
apparatus can altogether obviate the necessity of watchful and 


intelligent hand regulation, especially when waterwheels are the 
prime movers. It should be remembered, however, that the 
variations in voltage which pass altogether unnoticed in ordinary 
service, and are practically of little account, are much greater 
than would be at first sight supposed. An evening passed in 
any station operated by water power teaches a useful lesson in 
this respect. Quite considerable occasional variations, particu- 
larly if slow, are far less objectionable than repeated or periodic 
ones of much less magnitude, such as are produced by "hunting" 
in a governor or overmuch fussing with the regulating devices. 
A governor should be " dead beat " even if something of sensi- 
tiveness is sacrificed to that end. 

In passing from the subject of generators, I need only say that 
polyphase machines present no startling peculiarities and possess- 
no mystical properties. All that is needful to produce a good 
polyphase dynamo is conscientious, straightforward, intelligent 
designing ; fads and overmuch ingenuity generally do more harm 
than good. 

Polyphase Generators as Motors. 

Polyphase, like other alternating current generators make good 
synchronous motors. In fact, they are decidedly better than others 
for this purpose, in that they are self-starting with more or less 
facility, and do not go out of step quite so easily as the single 
phase machines. They are, as it were, more flexible. They start 
really as induction motors ; that is, they may properly be re- 
garded as induction motors having a revolving primary element 
and a non-laminated fixed secondary without windings, exerting 
torque simply by virtue of induced currents in the pole-pieces. 

Naturally they cannot start very efficiently under these con- 
ditions and for motor purposes it is much better somewhat to 
modify the structure, so as to provide secondary windings or other 
devices to approximate the effect of a genuine induction motor. 
Nothing very complicated in this line is necessary, and it is quite 
easy to produce a synchronous motor that will be self-starting- 
even with a considerable load of shafting. In the Eedlands 
tripliase plant for example, the motor of 160 h. p. is belted to a 
short countershaft mounted in a timber frame and carrying twa 
large pulleys. The smaller of these, drives by a 36-indi belt a 
wooden wheel 18 feet in diameter mounted on a crank shaft 
that drives two large ammonia compressors. A pulley on thia 


shaft is belted back to the framework aforementioned, and drives 
a force pnmp for the ice-making machinery, a circulating pump 
for the water jackets of the compressors, and a small ice elevator. 
All this machinery is brought promptly up to synchronism by 
the motor without the intervention of clutches. The starting 
torque is thus quite sufficient for most ordinary uses to which a 
large motor is likely to be put. 

The synchronous type of polyphase motor is especially adapted 
to large units. Being a non-laminated structure it is easier to 
build and somewhat cheaper than an induction motor of the same 
size would be, and furthermore it possesses the advantage of in- 
troducing no lagging current whatever into the line, except at 
the moment of starting. While this lagging current is not of 
great moment on ordinary lines, it may as well be avoided where 
by so doing a niachine equally as good and cheap can be obtained 
without any additional complications. With large units too, there 
is generally less need of a very great starting torque, and con- 
sequently induction motors are far less necessary in the large 
sizes than in the smaller ones. 

There is no practical difficulty whatever in building or opera- 
ting these large synchronous self-starting motors and they are 
likely to come into extensive use. 

I can hardly do better in closing a description of polyphase 
generators and synchronous motors than to give some of the data 
obtained from tests of these machines. 

A 260 K. w. machine showed at full load about 94 per cent, 
commercial efficiency. On a continuous run of 9^ hours under 
full load the heat developed was as follows, the figures given 
being rise in temperature of the several parts above the tempera- 
ture of the surrounding air : 

Field colls 18«C. 

Yoke 7'.5C. 

Armature teeth Si** 0. 

Armature heads 20° 0. 

Taking these figures in connection with the data already given 
for exciting current, a pretty clear idea can be obtained of the 
general character of a modem polyphase generator or motor. 

Induction Motors. 
Perhaps the most striking characteristic of the polyphase sys- 
tem is the use of the polyphase induction motor, obviating as it 


does necessity for moving contacts, and enabling the ready em- 
ployment of forms of winding which give remarkable immunity 
from the ills to which continuous current motors are heir. In 
all that has been said about these motors there has been an un- 
fortunate absence of exact data, particularly as regards their 
ability to start under heavy loads, the current required at start- 
ing, the current required when running light, the lag factors, 
light and loaded, the variations of speed under varying load, and 
other characteristics which are of direct practical importance in 
the use of such apparatus. 

Of the various polyphase motors which have been heretofore 
described, some appear to have had certain of these above-men- 
tioned properties well developed, and others very badly devel- 
oped. None so far as I know, seem to have reached any carefully 
considered balance of the properties necessary to make a good 
commercial motor. 

It is my purpose now to take up the induction motor as it can 
be, and is developed at the present time, and to give some plain 
facts concerning its actual properties ; not determined from single 
experimental machines but from types which have been pretty 
thoroughly tried. I feel it especially desirable to do this in 
order to correct some of the errors into which those who are 
even well informed about polyphase machinery, have but too 
readily fallen. 

The induction motor consists essentially of two laminated 
structures, one fixed and the other revolving, and each wound 
symmetrically for phases more or less in number according to the 
system on which the machine is to be employed. It may be 
considered as a transformer with its magnetic circuit imperfectly 
closed, and of which one member is free to revolve. For me- 
chanical reasons I think it is generally preferable that the primary 
element which receives the higher voltage should be fixed, and 
the low voltage, secondary element, movable. By this arrange- 
ment too, all necessity for moving contacts is avoided. For 
certain specific purposes the reverse of tliis plan may now and 
then be advisable. 

As to the general properties of these machines, I can hardly sum 
them up better, than to say that they behave in a manner strik- 
ingly like well designed shunt-wound continuous current motors, 
having, however, the advantage of being simpler and of having 
no commutator. Even their eflSciency is closely similiar to that 


of continuous current motors of the same size, both as regards it& 
maximum value, and its value under moderate loads. The 
hjsteretic losses and those due to parasitic currents are, however, 
a source of inefficiency that has to be carefully considered in 
order to reach a satisfactory result. 

These losses are located in large measure in the primary ele- 
ment of the motor, and would apparently indicate the desirabil- 
ity of making this the revolving, and naturally smaller part of 
the machine. The advantage, however, of using a very simple 
and substantial winding on the revolving element, is too great to 
forego for the sake of a little saving in hysteresis. 

Induction motors can be made to start readily under load, yield- 
ing when properly designed for the purpose, a starting torque up to 
four or five times the full load running torque. Even more than 
this can be obtained if it be needed, but for most practical pur- 
poses, running torque is quite sufficient, and it is perhaps best 
generally, not to design motors with abnormal starting powers in 
view, regarding such rather as special types. As in continuous 
current work, a motor fitted for unusually heavy strains is not 
necessarily the best all around machine. 

For everything except extraordinary requirements such as may 
be sometimes met in hoisting, a uniform design and rating may 
be conveniently kept, as it is very easy to regulate the torque 
and the current required to produce it within wide limits, by 
varying the resistance included at starting in the secondary cir- 
cuit. I know of no motors without such a starting resistance 
that are capable of giving any considerable starting torque with- 
out an enormous initial rush of current, and even were one de- 
signed to secure a good torque without armature resistance, it 
would be almost certain to exhibit various other undesirable 
qualities that would more than ofifset the advantage. 

The office of the starting resistance is two-fold : First, it limits 
the possible current in the armature so that it will not beat back 
the induction from the field ; that is, it sets a limit on the arma- 
ture reaction. Second, it limits also the lagging in phase of the 
armature behind the field. There is a particular resistance best 
suited to each case, for which the torque is a maximum, at the 
given voltage. Any variation from this value will diminish the 
torque, the current meanwhile rising or falling according as the 
resistance is diminished or increased. This critical resistance 
should be found and used whenever it is necessary to start under 



.{Jan. 17, 

abnormal loads. At a certain second value of the armature re- 
sistance, the torque per ampere will be a maximum, and this 
determines the best resistance to be used for cases where a large 
static torque is not necessary. Somewhere between these points 
will be found the best working resistance for practical purposes. 
The first point named does not call for impracticable current, 



































^ A 



\ — / 



/ y 




































D B 




9 A 





3. TC 



IE r 







Fig. 3. 

noh the latter for inconvenient torque, if the motors be properly 

In using a starting resistance I prefer to fix it within the arma- 
ture spider and so to avoid all need of collecting rings. Save for 
this device, moving contacts of some sort must be used either to 
lead the pripiary current into the revolving element, or to con- 


Bdct the resistance to the secondary, either of which procedures 
is objectionable, particularly the latter. 

There is no subject connected with polyphase work which 
has been the theme of more hasty conclusions and ill-advised 
criticism than the current required by polyphase motors in start- 
ing. The popular verdict pronounces it enormous, an opinion 
generally derived from hearsay, or from experiments with poorly 
designed motors, often with armatures of the squirrel cage type, 
than which nothing is more ineffective in starting, if the motor 
be decent in other respects. 

Nothing can be more grossly exaggerated than this commoB 
idea of immense starting curi'ents. The best way to refute it 
permanently is to give exact experimental figures. The annexed 
curves (Fig. 3) will show very plainly the facts in the case. The 
torques given are genuinely static, being obtained by fitting a 
horizontal brake beam to the shaft of the motor and resting a 
stud on the beam upon a platform scale. The resistances used 
were of manganin strip. The currents were obtained from a 
current indicator standardized from a Siemens dynamometer, 
and the readings were made after the pointer had come to rest, a 
precaution very necessary, as the instrument was not at all dead 
beat The current thus obtained is a time maximum for the 
given torque, the armature being permanently clamped at rest. 

In Fig. 3 the relation between starting torque and current is 
very clearly shown, as well as the importance of the starting re- 
sistance. In the figure the curves Aj, A2, As belong to a 10 h. f. 
triphase induction motor, and Bi, b^, Bs to a similar machine of 
5 H. p. 

Ai shows the eflEect of varying the resistance in the secondary 
on the relations between starting torque and current, the voltage 
being kept normal and constant. A2 shows the variation of 
torque with current for a given fixed resistance, the voltage 
being varied, and the resistance being such as to give heavy 
torque. As is the same as A2 except that the resistance was such 
as to give very moderate starting currents. Full load torque was 
35 lbs. 

Bi, B2, B, are similar curves from a 5 h. p. triphase motor, the 
full load torque being 17.5 lbs. Now examine the curves. In- 
stead of abnormal currents being required in starting, each of 
the motors under examination will develop full running torque 
on considerably less than full load current. At full load current. 



[Jan. 17, 

in fact, each of them gives some fifty per cent, more than run- 
ning torque. And this condition of things is not in the least 
exceptional — it will be true of any properly designed motor 
unless it be intentionally adjusted to have a very great starting 




80 100^ 120 140 

Fig. 4. 


180 200 220 

effort at normal voltage, as shown in Fig. 4 which is a curve 
from a 10 h. p. motor. Here curve a shows the relation between 
current and torque with a carefully adjusted resistance, and curve 
B the same relation without armature resistance. In this latter 
case we have reproduced just the state of affairs that is encountered 




when one attempts to start an induction motor by a rheostat in 
the primary circuit. A comparison of a and b tells its own 
story as to the advisability of this procedure. The results are 
never comparable with those obtained with a resistance in the 
secondary tinder similar conditions. Curve o gives the torque 
of a special 15 h.f. motor, full running torque being 52.5 lbs. It 
may be well here to note that an ohmic resistance cannot be re- 
placed by an inductive resistance for the purpose under considera- 
tion, as the armature current is thrown thereby so much out of 
phase that no even tolerable results can be obtained. In leaving 
the subject, 1 need only say that there is no particular difficulty 
in constructing a polyphase motor that will give any torque that 
can reasonably be asked, and with a starting current by no means 
disproportionate to the result obtained. 





— ■ 








— " 



















1 i 

\ A 




) G 

\ 1 


1 1 

Fio. 5. 

The next thing that comes up for consideration, is the power 
factor which may be expected in polyphase motors. By the 
power factor we mean the ratio between real and apparent watts 
which measures the angle of lag introduced by the motor. It 
goes without saying that a high power factor is desirable both on 
the ground of requiring less current capacity in the lines and 
generators and on accotmt of less inductance in the circuit, 
and consequently less trouble in keeping up the proper voltage. 
In motors of various designs, the power factor is probably the 
point in which there is the greatest and most serious variation. 

Fig. 5 gives three curves showing the variation of power 
factor with load, in three typical three phase motors. Curve a 
is the power factor of a 15 h. p. four-pole motor designed to run 



[Jan. 17, 

at 50 cycles. Curve b is from a 5 h. p. motor of closely 
similar design. Curve o is from another 6 h. p. motor which 
had specially valuable characteristics in the matter of power 
factor. The last curve shows what may be accomplished by de- 
signing with special care for a high value of power factor. 

Now the points to be noticed in these curves are the follow- 

1st. That in all three motors at and near full load^ the power 
factor is closely in the vicinity of 90 per cent. — ^in curve o 
fully 94 per cent. 

2d. The power factor even at half load is still good. In the 
15 H. p. motor it is 84 per cent. ; in one of the 6 h. p. motors it 
is 75 per cent.: and in the other 79 per cent. In fact the half 














i 4' 









— ^ 









e 9 10 11 12K.W 

Fig. 6. 

load values for the power factor, as here shown, are greater than 
the full load power factors of European three phase motors 
which have been described up to date. The Dobrowolsky 5 
H. p. three phase motor^ has a full load power factor of but 
.68, while the power factor of a small Oerlikon motor (as de- 
scribed by Mr. Kapp from actual tests) is but 74 per cent, at full 
load. We must not, however, attach too much practical import- 
ance to very high power factors, for the reason that those shown 
in Fig. 5 are already within the range of first-class commercial 
work. Perhaps we may better investigate the relation of this 
power factor in actual operation by reference to Fig. 6 which 
shows the relative currents required at different loads by three 
1. Electrical World, April 22, 1893. 


sizes of three phaae motors. Curve a is for a 5 h. p. motor, 
curve B for a 10 h. p,, and curve c for a 15 h. p. For 
convenience we will call the ordinates total amperes required. 

Suppose now we have a dynamo running an exclusively motor 
load composed of these three sizes of machines and let us see 
what will be the actual conditions when the motors are running 
fully and partly loaded. Let us suppose the load to consist of 
10, 15 H. p., 10, 10 H. p., and 20, 5 h. p. motors running at full 
load. The current demanded (as by the curves on Fig. 6 for this 
combination, is 1950 amperes, and the average lag factor will be 
at least 88 per cent., which could readily be raised to 90 per cent, 
if it were desirable to pay special attention to thai feature of 

At half load the aggregate current required would be 1125 
Amperes — 57 per cent, of the full load amperes — and the average 
power factor 81 per cent. Even at one-third load the condition 
of things is by no means as serious as it might be, inasmuch as 
the aggregate current is 890 amperes— 45 per cent, of the full 
load amperes — and the power factor is still 72 per cent. The 
generator can readily take care of any of these loads without 
43eriou6 trouble from the lag introduced on the line, and even 
supposing that the total generator capacity be taken at 200 h. p. 
instead of 350, the aggregate capacity of the motorsj it would 
still be able to operate all the motors at half or one-third load, 
without unreasonable over-excitation on account of the lagging 
current, as may readily be perceived by reference of figures for 
excitation and the lagging current which 1 have previously 

Of course it is possible to reduce the lag factor perceptibly by 
the employment of condensers, but it is certainly an open ques- 
tion whether so long as it is practicable to obtain power factors 
in the vicinity of 90 per cent., and even above it, without using 
condensers, the extra gain is worth the extra complication. 
There will certainly be some value of the power factor which it 
will not pay to increase by adding condensers — just what value it 
is hard to predict until condensers have come into more general 
use. Even if condensers be used, they will not necessarily bring 
up the power factors, at moderate loads, to any very startling 

The place where it is most desirable to retain as high a value 
-as possible for the power factor, is where the motors are to be 



[Jan. 17, 

used on long circuits, in which case it is important to keep the 
general inductance of the system low. In this connection, how- 
ever, nearly all the long distance propositions which I have in- 
vestigated — and their number is very great— require the use of 
mixed apparatus— induction motors, synchronous motors and 
lighting, in which case the general energy factor can be kept fairly 
high, particularly as the synchronous motors can even be made 
to compensate in large measure for the presence of the induction 

A word now with reference to efficiency. Fig. Y gives a pair of 
efficiency curves, one of them, a, taken from a 5 h. p. motor, the 
other, B from a 20 h. p. machine. The 5 h. p. motor had four 
poles, the 20 h. p., six, and both were intended to run at 50 









123466769 10 1 

Fig. 7 

I 12 13 14. 16 16 1 

7 18 18 20K.W.. 

cycles. A glance at the curves will show that their full load 
efficiencies were respectively a trifle over 82 and 88 percent., the 
larger motor in particular retaining a very uniform efficiency 
from half load up. These figures can be praised by paying the 
same attention to the iron as in the case of transformers which 
do not have a movable secondary. 

The two in question had stampings of ordinarily good arma- 
ture iron without extraordinary precautions is annealing. From 
a special 5 h. p. motor I have obtained a full load efficiency of 
very nearly 90 per cent. I can hardly refrain from comparing 
these efficiency tests with those of motors of similar size and of 
the synchronous alternating type, as made by Ganz and Co., and 
described in the report of the Frankfort Commission, the period- 
icity being 42. In this case the maximum efficiency of a 25 h. p^ 


motor was Sd per cent, the half load efficiency about 80, while 
the maximum efficiency of a 5 h. p. motor was but 80 per cent. 
All these are, of course, commercial efficiencies. Motors of other 
sizes will bear about the same relation to the figures ^ven as in 
the case of ordinary continuous current machines,^ the two shown 
being thoroughly typical. 

To conclude the matter of efficiency I annex the weight effici- 
encies of fi^e sizes of induction motors : 

H. P. Weight per h. p. 

5 108 

10 66 

16 68 

20 78, 6-pole 

100 66, 8-pole 

These weights compare extremely well with those of any stan- 
dard direct current machines, and were light weight a special ob- 
ject, could readily be considerably improved. 

Much has been said regarding the effect of frequency on the 
properties of induction motors, and I am sorry to say, most 
generally from a purely theoretical standpoint. Judging from 
numerous experiments between 30 and 70 cycles, I am strongly 
of the opinion that within this range not much is gained or lost 
by varying the frequency, provided the motors are designed with 
reference to the particular frequency at which they are to be 
used, although as in static transformers, increased frequency tends 
to increased output. As reasons quite independent of the char- 
acter of the motors which can be obtained, limit the frequency 
advisable in power transmission work to something like the 
working range just mentioned, I do not think the gain is one of 
sufficient importance to cause a choice to be made of one 
moderate frequency rather than another. For example, low 
cycles compel the use of uncomfoi'tably large 2-pole induction 
motors, while at high cycles even very small motors must have 
6 or 8 poles. At 10 cycles the higheet possible motor speed is 
600, at 100 8 poles are necessary to get any decently low speed. 

I will now briefly pay my respects to what are really unsym- 
metrical polyphase motors, that is, the so-called non-synchronous 
single phase motors, which start by means of some phase differ- 
entiating device, whereby a derived phase is employed to pro- 
duce a sort of rotary pole. The result is what may be character- 
ized as an elliptical rotary magnetization, as distinguished from a 


circalar one, and consequent loss of efficiency. In general they 
start and run like bad polyphase machines, have a less output for 
the same size, and a lower efficiency. These statements are amply 
borne out by figures which have been published on the Oerlikon 
three phase and single phase motors, showing that the latter have 
for the same output, greater weight and less efficiency. The 
power factors of such motors are decidedly below those of poly- 
phase motors. I believe that it would be possible, however, ta 
design a motor of this class which should have nearly us good 
properties as the polyphase motors I have described, but it would 
be costly, and would perform much better, if regularly wound for 
two or three phases. In other words the same structure that 
would give a good single phase motor would give a phenomenal 
polyphase one. With single phase induction motors, the use of 
condensers would be decidedly advantageous, and they thus- 
might be made fairly operative even at rather high cycles. 


The static transformers used for polyphase work being, in all 
essential particulars, like those with which the public is already 
familiar, little need really be said on this score except that in 
most cases the average efficiency of transformers in polyphase 
plants, will be found decidedly better than in the lighting plants 
now in operation, principally for the reason that larger units are, 
and will be, generally used. 

The question of frequency is of more importance, however, 
and the general facts in the case are that the low frequency 
transformers, other things being equal, are the more bulky and 
expensive, though not in a very great degree. Within the work- 
ing range for power transmission work, the difference is, as in the 
case of motors, not so considerable as entirely to overshadow 
other considerations which arise in specific cases, such as those 
of permissible inductance, size of units, permissible heating, loss 
of energy generaUy under the particular circumstance considered,, 
and the like. 


The convenient and efficient use of rotary converters is a very 
characteristic advantage of polyphase systems. These machines 
have already been considerably discussed, and it is perhaps suffi- 
cient to say, as regards their general character, that they are, in all 


essential particulars^ closely similar to standard direct current 
machines. They are self-starting, can readily be compounded 
for constant potential, and behave in all respects like direct cur- 
rent generators. It is possible to make a similar single phase 
machine of somewhat smaller ontpat for the same size, and non- 
self-starting. In actual operation they are highly satisfactory 
and appear to give considerably better results than any methods 
which have yet been brought forward for converting alternating 
into direi-t current by any species of commutation. 

As a good many of our friends who are not deeply versed in 
the electrical industry say, electricity is in its infancy, and from 
all I can learn, the art of directly commuting an alternating cur- 
rent and getting a decent direct current is very decidedly in its 

In the use of notary transformers, the frequency is a considera- 
tion of much more importance than in the case of transformers or 
of induction motors. It is a matter of some diflBculty to build 
a large unit for high frequency, the difficulty being encountered, 
as might be expected, in the commutator. It is probably as easy 
or easier to build a 500 k. w. unit for 30 cycles, as it is to build 
a 10 > K. w. unit for 60, so that wliere, for any cause, it becomes 
necessary to use a large number of rotary transformers, this 
necessity may quite control one's choice of the precise frequency 
to be employed. 

In all practical cases of transmission of power, rotary con- 
verters require the use of transformers for reducing the line 
potential, inasmuch as if they are not used, the voltage on the 
main line will necessarily be so low that it would be quite as well 
or better to transmit the continuous current directly. 

The System. 

In planning a polyphase system, one of the first questions that 
naturally arises, is that of frequency in its relation to the machine- 
ry, the line and the service. So far as the first count is con- 
cerned, one can say that while in general the higher the frequency 
the less the bulk of the apparatus, each size of unit has a certain 
frequency which gives the greatest economy in material and 
labor. The larger the unit the less this frequency. The rate of 
change, however, is rather slow, and as an actual result of de- 
signing with economy in view, the largest units as yet proposed, 
6,000 to 10,000 H. p., will show very little difference in economy 


between say 25 and 40 cycles. In discussing frequency, theorists 
have often fallen into the grievous error of considering only the 
generating units. The load of transformers and motors is of 
equal, in fact of greater importance, since the actual aggregate 
6o8t is far greater, and in nearly every practical case, will call 
for a frequency considerably higher than in the case of the 
generating units. One might, for instance, by ignoring this fact, 
aave $10,000 in the generators and lose $50,000 in the trans- 
formers and motors. 

So far as the line alone is concerned, the lower frequencies are 
the better, since they reduce inductance and static effects. 
Nevertheless too much importance should not be attached to 
this, since the vast majority of cases can be handled with perfect 
success at a frequency of 50 or 60 '^. For example, one can trans- 
mit 1,000 K. w. at 10,000 volts a distance of 20 niiles or so on a 
single circuit (three phase) and still have the total impedance 
less than double the ohmic resistance. In practice, such a system 
would generally too, carry a considerable output in synchronous 
motors which can be, and should be, made to serve as gigantic 
capacities, reducing, or even annulling, the inductive drop. 
Finally we come to the service. There is a frequency below 
which incandescent lamps cannot be operated without percep- 
tible flickering. This frequency certainly varies with different 
observers and perhaps also with the same observer at different 
times. Professor Mangarini and others have placed the limit as 
high as 40 or 50 ^. The average eye, 1 think, is less sensitive 
than this. Personally, the limit seems to be about 30 ^ cer- 
tainly over 25 ^ and under 35 '^, and a number of other ob- 
servers unite on about these same figures. It would be almost 
impossible not to notice variations at 25 '^, and they are most 
annoying, not to say intolerable : 30 '^ certainly leaves a small 
enough factor of safety. 

Alternating arc lights are even more sensitive. The very best 
carbons begin to give considerable trouble at 40 '^, and with 
most carbons, flickering is perceptible at 50 or even at 60. 

Inasmuch as most large systems find the arc lighting desirable, 
and practically all must use many incandescent lamps, the fre- 
quency should certainly be kept above 30 ^ and preferably above 
40. To go below 30 ^ is wantonly to throw away the most 
characteristic advantages of the alternating system, and in the 
vast majority of cases is not worthy of serious consideration. 



To my mind the most serious consideration in long overhead 
lines and all underground lines is static capacity. Particularly 
is this the case when the current waves are non-sinusoidal, for in 
such case we can get phenomena of resonance not only from the 
fundamental frequency which is generally low enough to keep 
out of the way, but from the higher harmonics as well. These 
are liable to produce discharges that will rupture almost any 
finite insulation For this reason the sine wave is highly desir- 
able, far more than from any considerations of eflSciency. I am 
sure, however, that a sufficiently close approximation to it can 
generally be obtained from a properly designed dynamo, and the 
inductance that generally exists, helps to muffle the higher har- 
monics. Resonance is generally in evidence on long lines how- 
-ever, and makes itself felt by a tendency to spark and sputter 
beyond the capabilities of the nominal voltage. It may prove 
advisable in some cases when dealing with non-sinusoidal waves, 
to give the line artificially a capacity that will not readily respond 
to the most prominent harmonics. I remember once experi- 
menting with a tuning fork with a sixth harmonic that quite 
drowned the fundamental, and it is quite possible to conceive of 
a dynamo with undesirable characteristics of a similar sort. 


The upper limit of practicable voltage is most uncertain: 
5,000 and 10,000 volts have been experimentally shown to be 
Available, and 15 to 25,000 possible If the conditions to be 
met render these voltages necessary, I think they can be handled 
well enough. The question really resolves itself into the com- 
mercial one of paying for the necessary precautions in insulation. 
A voltage will be reached, however, at which these precautions 
will cost more than the extra copper required for a lower voltage, 
and*here commercial necessity will call a halt. This point, how- 
ever, has yet to be experimentally found. 

Whether these high voltages should be derived direct from the 
machine, or obtained from step-up transformers, is a question 
which has been often discussed. The high voltage dynamo in 
very large sizes has the advantage in first cost over one of low 
voltjige plus transformers, but runs afar greater risk of serious 
injuries. Besides, what is of practical impoilance, is that with a 


high voltage dynamo, if anything happens, the dynamo is gone. 
Take a 10,000-volt dynamo, let a rupture once get started, and it 
is a case of ruined machine practically every time. When yon 
have transformers and a bum-out, you may have lost one or more 
transformers to be sure, but probably you are running banked. 
Indeed it is very foolish to put all one's eggs in one basket in such 
a matter. So instead of losing a 6,000 or 10,000 h. p. dynamo 
you may lose only a transformer of 100 k. w. or something of 
that kind. Although we would all like to use high voltage 
dynamos on account of economy in first cost, until they have 
been practically proved to be suflSciently free from break-downs, 
I should say it would be very poor practice to use them exten- 
sively, although they are now being tried somewhat and I hope 
we shall find the results to be good. 

I am now compelled to disturb a very much mooted question? 
that is, the amount of copper required for polyphase lines. It 
goes almost without saying that all polyphase systems using & 
complete circuit per phase will require the same amount of cop- 
per as an ordinary alternating system. Some statements have 
been going ai ound recently as to the relative amount of copper 
required for the alternating system and for the direct current, 
which, I think, are very largely founded on a misconception. 
They seem to proceed on the principle that in all cases where 
alternating currents can be employed, we may consider direct 
current as a straightforward competitor. This is certainly not so. 
In a vast number of cases where we have to deal with voltages 
somewhere near the limit of insulation, the direct current is out 
of it from the start, and is not to be considered at all. In the 
second place it is a grave question whether the electrolytic 
strains of the direct current are not under some circumstances, 
perhaps many circumstances, fully as bad as the electrostatic 
stresses caused by the somewhat higher alternating voltage. That 
is a subject that will have to be studied very thoroughly before 
we shall know quite where we stand. Now as regards the cop- 
per required for polyphase circuits which are interlinked, I 
went to the trouble, for the sake of informing a few recalcitrant 
persons who do not want to believe a mathematical demonstra- 
tion; of having an experiment actually made, setting up a tri- 
phase generator with a bank of lamps in the laboratory, and try- 
ing the relative conditions as between a single phase system and 
a triphase system with interconnected circuits. The experiment 


was performed in an exceedingly simple manner. Four non-in- 
ductive artificial lines were prepared, and using two of these in 
parallel, a certain amount of energy was transmitted to lamps 
banked at the other end. A single phase current was used, and 
the losses carefully measured. Then one of the lines, this ex- 
periment having been made, was removed, and the remaining 
three wires worked on the triphase system, transmitted the same 
energy at the same initial voltage, with the same loss, showing 
conclusively, as might be expected, that theory in the matter is 
quite correct and that the actual saving of copper in the inter- 
connected triphase system is twenty-five per cent. The experi- 
ment came out within one per cent, of the calculated amount^ 
and this must be true whatever assumption is made regarding 
the conditions under wliich we are to transmit power. Take a 
plain alternating system at any voltage you please, and compute 
the copper on any series of hypotheses that may suit your fancy, 
yet the interconnected three phase will do the same work, and 
do it just as well with three-fourths the outlay for copper. It is 
precisely equivalent in its net result on the economy of the sys- 
tem to raising the voltage about fifteen per cent, without, how- 
ever, any added strain on the insulation, and I think the man 
would indeed stulify himself who would deny that raising the 
voltage affects the economy of the system. Aside from all other 
questions concerning it, an additional advantage of this particu- 
lar type of circuit is the greatly reduced inductance for the same 
energy transmitted under similar conditions, amounting only to 
about 57 per cent, of that found on a single phase circuit. 
This reduced inductance, which after all is in part attributable to 
the less cross-section of copper required, or is rather interlinked 
with it, is perhaps the greatest advantage that this particular 
system has, and makes it of extreme value on all very long lines* 
There are not very many points which differentiate triphase 
from other polypliase systems, and so far as my knowledge goes, 
the two that I have mentioned are by far the most important, 
more especially that which relates to inductance and incidentally 
to capacity — ^getting around as it does the "bugs" which are 
most dreaded on very long distances. So much for some of the 
practical considerations regarding polyphase plants. 

I may say that we now have in this country five polyphase 
plants running, not all of them very big, but perhaps averaging 
as large as the foreign ones. One of them, that of my friend 


Stanley at Pittsfield, is a two phase plant. The others at 
Taftsville, Conn. ; Concord, N. H. ; Hartford, Conn., and Red- 
lands, CaL, are triphase. Of those four tri phase plants, one is 
particularly concerned with running induction motors. It is a 
small temporary generator installed in the present station, and 
taking care of several induction motors. Two others— those in 
Connecticut — are synchronous plants, the Taftsville plant con- 
sisting of a 300 H. p. generator and similar motor, and the Hart- 
ford plant being of like size but an older type of machine. The 
Taftsville plant I started only yesterday. The purpose of the 
plant is to drive a cotton mill. Yesterday afternoon a synchro- 
nous motor was started up — and it did start quite readily — at the 
Taftsville end of the line, the power station being four and a 
half miles distant and the voltage l>eing 2,500. When the motor 
got up to speed, the motor clutch was thrown in so that 
the motor was running in parallel with the engine, and the load 
was then shifted from the engine to the motor without pro- 
ducing any noticeable disturbance at all. The shuttles moved 
sluggishly for a few strokes, and then went up to their normi^ 
speed, the service on the looms, which are occupied with weav- 
ing specially delicate cotton fabrics, being quite uninterrupted. 
In the course of the afternoon when it got quite dark at the 
power station, so that there was not suflScient light to attend to 
the long lines of shafting, the reverse process was put in play. 
The engine was started up in parallel with the motor, and then 
the motor was cut out by its clutch and the plant shut down, all 
without creating any disturbance. 

The Redlands plant is rather the most interesting of the four 
three phase plants, inasmuch as it is a mixed plant running large 
synchronous induction motors and lights oflF the same generator. 
Kedlands, Cal., is a small city not far from San Bernardino and 
at the head of the valley that sweeps down towards the Pacific. 
The power station is seven and one half miles from the centre of 
distribution, and nine and one half miles from the extreme end 
of the circuit. About four and one half miles from the power 
station is an artificial ice plant where is installed a 150 h. p. tri- 
phase synchronous motor. There are two or three small motors 
and a considerable number of lights running in the city of Red- 
lands itself. I started up this plant the 7th of last September. 
That is the first triphase plant of any magnitude that we put in 
operation on this side of the water. My experience with it was 


very satiBfactory. The power house is in a most inaccessible 
location, and getting the generators there was no small job, but 
about a week after they reached Redlands I had the plant run- 
ning and turned on lights. The point in which I was particu- 
larly interested was the performance of the motor, it being of 
the synchronous type and having a very unpleasant load to start 
with. The ice plant was one of what are called the pipe variety^ 
where the compressed ammonia is made to expand in great tiers 
of pipes on which the ice forms in gigantic icicles which grow 
together into great barriers of ice that are afterwards cut away. 
There are about twenty miles of pipe in the plant, and for three 
weeks, perhaps, we had amusement in starting up that motor, 
pumping up pressure on the receivers, shutting down, testing 
pipes, then starting up and doing it over again. So we had a 
fine opportunity to observe how the motor acted when it started,, 
and it started extremely well. On one occasion it started alto- 
gether too well. It was belted to two large ammonia compres- 
sors, and the very practical men who were running the ice plant 
looked with something of contempt on the small size of the 
motor. It did not look nearly as big as an engine ought to, and 
I think they had a sneaking suspicion that it would not start, or 
even if it did start, it would not do so with any regularity. One 
day I caught the superintendent of the plant standing behind 
the cylinder of one of the compressors shutting off the main 
valve, while the motor was running in synchronism. I told him 
that he had better quit, because if he did not, he might go out 
through the side of the house with the end of the cylinder just 
behind him. He quit temporarily. But about a week later, 
when I was in the city of Hedlands, they started up and forgot 
to open the by-pass valves which allowed the motor to come up 
smoothly without any excessive load — purely through accident, 
of course. The result was, that the motor made about ten turns. 
The big driving wheel, 18 feet in diameter, then proceeded to 
get in its work, pulled the pillow-blocks off both compressors, 
snapped the castings which supported them and linked them to 
the rest of the compressor, as you would snap a pipe stem, tore 
the end bearings completely off, dropped the wheel into the pit, 
and sprung the shaft. All that, was the result of about ten turns 
of the motor, starting absolutely from rest and starting as an in- 
duction machine. After that experience the proprietors of the 
ice plant looked on the motor as ''heap big medicine." We had 


no trouble whatever in parallel mnning in the generating plant. 
The generators, 250 e. w. at 2,500 volts would go into step and 
run together perfectly well. No artificial load was used in 
throwing them in. If the load were on one, the other was simply 
brought up and thrown in with it. It was not often that we had 
occasion to run them any length of time in parallel — only for a 
few hours and usually simply in changing over. But there was 
not a particle of difficulty. They ran as smoothly as two railway 
generators would. So that with a machine which has a compara- 
tively small armature reaction and a frequency of about 50, these 
tri phase generators will run in parallel as nicely as if they were 
direct current. 

We were also somewhat interested in seeing if there would be 
any trouble from unbalancing on the line. We had heard a good 
deal about it, and the Eedlands company had been told a great 
deal about it by kind friends, so that we were much interested 
in seeing the effect. The practical result was, as it will be in 
every case where even ordinary intelligence is exercised in plan- 
ning the plant, that it did balance. It is perfectly true that a 
triphase interconnected circuit, if very unequally loaded on the 
three branches is liable to get out of balance somewhat. It may, 
if conditions are unfavorable, get out of balance quite a little. 
If conditions are as favorable as they can readily be made, you 
will never know that there is such a thing as lack of balance. 
It does not begin to be as sensitive as a three-wire system. In 
fact all the abuse heaped on the lack of balance in the three 
phase system was poured on with double vigor years ago when 
the three wire system started. All the sore-heads and old fogies 
swore by all that was holy, that the three wire system would not 
balance, and to-day a very large proportion of all the incandes- 
cent central stations using continuous currents are running three 
wire. I buppose that we are to go through the same experience 
with the three phase. It is perfectly true that the system will 
be unbalanced in very unfavorable conditions, but if ordinary 
sense is used in arranging the plant, you will never hear of any 
trouble whatever from it. 

Another thing that we were very much interested in, was the 
effect of the big synchronous motor on the lamps. It did not 
have any — which was rather a surprise. I should certainly have 
been prepared to find some trouble from that big motor — as big 
as the entire load of lights. But except at the moment of start- 


ing it gave no trouble whatev^er, and inasmuch as there was 
never any need of- starting the motor when the lights were on, 
as we had two generators, it practically worked with entire suc- 

I regard that experience in Redlands as most satisfactory, be- 
cause the machines were thoroughly modern, the plant was laid 
out for a three phase plant and was operated under ordinarily 
favorable conditions. There is one thing I should mention with 
respect to it, which I regard as of great importance, and that is 
the matter of goveraing water wheels. That is the bete noir of 
every electrical engineer. Waterwheel governors mostly do not 
govern, at least with anything like accuracy. When the Eed- 
lands plant was first started, the governor could not be depended 
on to hold the voltage constant within fifteen per cent., and it 
would hunt in the most vicious manner. Afterwards a change 
was made in the governor. The double cone friction arrange- 
ment which had been used to work the exciter shaft which drove 
the constant speed side of a Pelton differential governor, waa 
thrown out after many attempts to make it work, and a small 
Pelton differential governor was put in its place, together with a 
moderate sized fly-wheel. That arrangement is holding the volt- 
age to-day perfectly well. It is the first waterwheel governor I 
have known to be actually operating with results entirely satis- 
factory to the electric company that is running the plant. That, 
after all, is the crucial test of a governor, not that it shall operate 
well before a committee of experts, or when it is being nursed 
by its inventor, but when it is in service twenty-four hours a day, 
and under such circumstances gives satisfaction. 

In concluding I can only say, I am convinced that polyphase 
work in one form or another has come to stay. It may not be in 
the form of two or three phase work just as we know it now ; 
but the principle is pretty sure to stay by us. I do not have 
many fears that the polyphase plants now installed will be 
scrapped in a few months by reason of some invention that will 
entirely supersede them. We have threshed over pretty thor- 
oughly the possibilities of the ordinary alternating current, and 
by far the most practical thing we have as yet, is the polyphase 
in one form or another. You " pays your money and you takes 
your choice." In some form it is going to stay by us long 
enough to make it worth while to develop it a little. 



The Pbesidbnt : — Discussion on Dr. Bell's paper is now in 

Dr. Bell : — I wish Mr. Stanley, whom I see seated over there, 
would tell us a little about his polyphase plant. He has the only 
two phase plant in the country. 

The President : — We would be pleased to hear from Mr. 
Stanley, not only on Dr. Bell's invitation but on our own. 

Mb. William Stanley : — I have been a very attentive listener 
to the very interesting paper Dr. Bell has given us, and I am 
sure I can appreciate a great deal that he has said. Those of us 
who have devoted a little time to this work and have, or think 
we have, got it to the point it has now reached, have met some 
obstacles that Dr. Bell has not mentioned. He passed them by 
very nicelv, but I know that he has had now and again to stop 
in his woric, and perhaps to reconsider his designs and so revamp 
his old ideas. While I agree with what the author has to say 
in general, I also differ in a great many points. I would like 
to speak of one or two. I do not believe m a system of power 
distribution that has a power factor of about four or five-tenths 
under commercial conditions. The average load of a large 

f)ower station varies from 30 to 40 per cent, of the maximum 
oad of all motors. At that load the power factor as given by Dr. 
Bell, if I correctly understand him, would be somewhere from 
45 to 55 per cent. In other words he would be sending out of 
his station as much magnetizing current for his motors, as he was 
sending out for doing work, rfow I do agree with the Doctor 
that it it were possible always to keep our motors loaded, we 
could neglect the lagging currents in the system. It is possible 
— and Dr. Bell has clearly shown us how— to regulate a multi- 
phase generator, but when the current in the generator lags 45 
degrees, the armature reaction cannot be very small, and although 
the generator may be regulated— and it can be as Dr. Bell has 
shown — yet the variation of potential on the system outside of 
the generator is almost fatal where we desire to operate lights 
and motors together. About fifteen or sixteen months ago we 
started in Pittsfield a 80 h. p. two phase motor and light plant. 
We are operating a saw mill, and part of a woolen mill. We have 
a 15 H. p. motor operating a printing press. We have three or 
four machine shops and some other small shops, and we are also 
distributing lights from the same circuit, the lights and motors 
being sprinkled about without any regard to whether the circuits 
are balanced or not. I have had a voltmeter on my desk day 
after day and watched the change of voltage as the lights and 
motors changed, went on and off in the afternoon, and the aver- 
age maximum change that I have been able to discover on the 
system has been a little over 2 per cent. It is the best, I am 
sorry to say, the most constant potential circuit that we have in 
Pittsfield to-day. 

1894.] DISCUSSION. 88 

This constant potential is entirely due to the fact that we have 
condensers on the motors^ supplying the lagging currents to the 
motor magnets. 

I am surprised to hear Dr. Bell advocate synchronous motors. 
I thought we had got by synchronous motors Mr. Kelly, my 
associate, has developed a very clever device for taking care of 
the lag of the magnetizing current on very large motors, which 
is this — if you take a synchronous motor, run it up to synchro- 
nous speed, either by an induction motor or any other means, and 
then over-excite its field so that the back electromotive force 
from the synchronous motor will be in excess of the applied 
electromotive force to it, the current in the synchronous motor 
will lag in respect to the motor, and lead in respect to the line, 
and by using a small synchronous motor in this way, we can re- 
place the condensers and furnish the lagging current for large 
induction machinery. And as it is possible to build large in- 
duction motors economically and to have them start — as has been 
shown — with great torque, I cannot for the life of me see the 
use of synchronous motors. I think we have got by them. 

But there is a point which Dr. Bell passed over which to me 
is verv important. He spoke of the question of frequency. He 
says that we ought to use any frequency practically between 30 
periods and 70 periods. Surely the Doctor knows, and we all 
know, that the torque of an induction motor is directly depen- 
dent on its frequency, and with your permission, I will put the 
formula on the board. 

W k — - ^ '^ ^ ^ (^ ^ ^ — 2 7Z Til) p M^ A? 

^^ //^ + (2 ;r 71 — 2 ;: /I,) D 


N = Number of pairs of poles. 

n = Generator frequency. 

n^ = Motor armature frequency. 

p = Resistance of armature. 

M = Coef . of mutual induction. 

A = Primary current in motor field. 

L = Coef. of self-induction in armature. 

This fornmla gives the work done by an induction motor ex- 
pressed in terms of the primary current. The work varies directly 
as 2 ;r times the frequency of the motor, multiplied into the 
motor slip times the resistance of the armature, times the mutual 
induction squared, into the primary current squared, and the 
work of the armature varies inversely as the impedance squared. 
This 18 the regular formula for the work that an induction motor 
can do. 


Now if we divide this equation by the frequency of the motor, 
we get this formula for the torque — 

for torque = ^ , . ,^ yJ- — -—« . 

Now this is a very interesting equation to me, if I understand 
it. If you double the frequency applied to a motor you do not 
change the numerator of this formula. But how about the de- 
nominator I Your impedance is less, because L is one-fourth (J) 
at double frequency, and as a matter of fact in all high fre- 
quency motors, the armature resistance should be lower with the 
same material used, because the chords across the armature ends 
are shorter, and you have the impedance term on the whole less; 
you also have the ratio of ^ to Z in the armature less, and the 
current in the armature lags lesg. So if you double the fre- 
quency in an induction motor, the lag of the armature current 
goes down very greatly. Now look at it once more. If you use 
the same material in two motors, one designed for double the 
frequency of the oth^r, and combine the material in a number 
of magnetic circuits for constant speed, you can then determine 
the relative armature reaction ft»r the two frequencies. Con- 
sidering the motor as a transformer for the low frequency case, 
we have the magnetizing power on the field A times t ampere 
turns, and on the armature the back magnetizing power is 
A T And amp. turns. Now if you double the frequency of 

the motor, you have 2 A over— amp. turns for your primary 


amp. turns, and for the back magnetizing power on the armature 
A X ^ amp. turns. In other words, the armature turns per 

magnetic circuit, are one-half for the higher frequency case ; con- 
sequently we do not have in high frequency motors the " blow- 
ing out " effect which is the most serious obstacle to motor con- 
struction. So I do not believe in low frequency motors. I 
believe in motors of 130 periods, if possible. We are operating 
our plant at Pittsfield at 130 periods. We are running a cotton 
mill at Ilousatonic at 60 periods, and we are using condensers to 
take care of our magnetizing currents. 

1 greatly appreciate the paper Dr. Bell has given us and trust 
he will continue as successfully as he has shown that he has pro- 
ceeded thus far. 

Mr. Charles P. Stkinmetz : —Having had some experience 
myself with polyphase motors, I may add a few short remarks : 

First, with regard to this whole system of rotary field motors, 
quite generally the opinion is expressed that this way of produ- 
cing motion by a rotarv magnetic field is a very new thing. But 
if you will look back into the records of science to some years 




before the oldest of us here were born — three-guarters of a cen- 
tury back— you will find a complete mathemjatical investigation 
and correct explanation, by Arago, of the experimental, fact, old 
already at that early time, that a disk or a short-circuited con- 
ductor is set in rotation in a revolving magnetic field. You will 
find there the mathematical proof and everything. These were 
the earliest rotary field motors. 

About fifteen years ago a further step in advance was made. 
You find mathematical and experimental proof of how a revolv- 
ing magnetic field can be produced by stationary electromagnets. 
That was in 1879. So lar with regard to the history of the 
polyphase motor 

ft may be of interest, perhaps, to the members, since the 

8 I I 

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\ \ 

\ I 

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Pig. 1.— 100 h. p. Three Phase Induction Motor, 88 Cycles. 

lecturer has so ably told us about the behavior of polyphase 
motors in general, to get some data of a 100 h. p. three phase 
motor, which I designed some time ago, and of which quite a 
number have been built and are now in successful operation. I 
have here plotted a curve giving the torque of the motor at vary- 
ing speeds. As abscissae are given the torque in lbs. at one foot 
radius— 1,000 lbs. corresponds very nearly to 100 h. p. As 
ordinates are plotted the speeds in per cent, of the synchronous 
speed. (See Fig. 1.) 

You see that when the motor is running light, the speed is 
practically synchronous. With increasing load, that is, mcreas- 
mg torque, the speed drops, though very slowly, by only 3 per 
cent, at full load, or 1,000 lbs. torque. With still increasmg 
torque, the speed drops faster and faster until a point is reached, 



[Jan. 17, 

at 1,800 lbs., where the torque curve bends around, that is, the 
torque as a function of the speed reaches the maximum, and if 
the speed decreases still farther, the torque decreases again more 
and more, the motor losing its torque, until at last only 440 lbs. 
torque are left at standstill. 

xhis is the running condition : very constant speed at all loads 
up to the maximum load, which can be carried by the motor, 
and lesser starting torque. 

Now, as Dr. Bell has told us, we can put resistance into the 
armature to increase the torque at low speed. Then we get a 
diflferent torque curve. The speed decreases faster with increas- 
inff torque and has dropped of already by 24 per cent, at the 
full load torque of 1,000 lbs ; but the torque constantly increas- 
ing with decreasing speed reaches the maximum of 1,800 lbs. 













































Fiu. 2.— 15 H. p. Three Phase Induction Motor, 125 Cycles. 

about at rest, that is, the torque curve ii intersects the zero lines 
at about 1,800 lbs. 

These are the two extreme cases : in one case the armature re- 
sistance is as small as possible, very steady speed, 3 per cent, 
drop at full load, and even at 80 per cent, overload only 9 per 
cent, drop of speed, but only small starting torque. 

The other extreme case is : very large starting torque, but 
greater drop in speed. 

In the first case the motor will keep verjr constant speed up 
to the maximum point, at which it can give 1,800 lbs., and 
loaded still further, it will come to rest ; in the latter case, with 
increasing load, the motor speed will steadily decrease until the 
motor comes gradually to rest at its maximum torque. Obviously 

1894.] DISCUSSION. 37 

any intermediate condition between these two curves, tlie curve 
of maximum starting torque and the curve of constant speed, 
can be reached by putting a lesser amount of resistance in the 
armature; and in reality in the 100 h. p. motor which I am 
speaking of here, an intermediate step is provided giving the 
torque curve in. 

Bat one statement I want to emphasize here : while the speed 
corresponding to a given torque can be varied by suitable re- 
sistance in the armature circuit to anything between curve i 
and standstill, no matter what the speed is, the same torque 
always corresponds to the same current, that is, the current de- 
pends upon the torque only, and not upon the speed of the motor, 
and the speed of the motor is independent of the torque or of 
the current, and merely depends upon the resistance in the arma- 
ture circuit, while the torque of the motor is independent of the 
armature resistance. 

This indeed is the case only in a properly designed motor. 
Obviously there is no difficulty in designing, or rather mis-de- 
signing, a motor which does not fulfill these conditions. But 1 
only refer to motors which are properly designed. 

Then, at full speed or at a standstill, the torque is a function of 
the current only; that is, the current is the same for the same 
torque, although the speed may be different, and can be any- 
thing from this maximum curve i to zero. I may add here that 
these curves were calculated theoretically originally, but after 
the motor was built and tested I had no reason to change the 
curve, because the observed values fell into this line i, etc. The 
drop was exactly 3 per cent, and it gave this torque. I may add 
here in fairness, that in reality the pre-deterraination of a poly- 
phase induction motor characteristic can be done with far greater 
exactness than that of any continuous current machinery — the 
behavior under any conditions of load, speed and anything else. 

The motor whose speed characteristic is given here in Fig. 1 
is a 100 H. p. motor running at 33 cycles. The frequency, how- 
BTer, has no influence whatever upon the behavior of the motor, 
upon its output, torque, etc. That is, obviously, one and the 
same motor when run at a frequency for which it is not designed, 
will, in general, work poorly, but what I mean is, that a motor 
can be designed for any frequency whatever, within reasonable 
limits, to give the same characteristics, that is, work at the same 
variation of speed, torque, current, etc., for 125 cycles as well as 
33 cycles, as you can see by comparing the diagram in Fig. 1 
with Fig. 2, which gives the speed characteristic of a 15 h. p. 
motor, which I built for I "26 cycles, that is, nearly four times the 
frequency of the motor given in Fig. 1. 

Hence, a motor designed for a frequency of 125 cycles be- 
haves at this frequency exactly as a motor designed for 38 cycles 
behaves at 33 cycles, supposing always, you know, that the motor 
is properly designed. 


Obviously, if you try to run a high frequency motor at low 
frequency, it will not give any decent result, and if you try to 
run a low frequency motor at high frequency, it will probably 
fly to pieces. 

But as long as you maintain the same correct magnetic and 
electrical design, you can get the same good features at any fre- 

Indeed one restriction has to be made here : if you go very 
high in the frequency, you have either to choose a very high 
speed, which is mechanically objectionable, or you cannot main- 
tain the Fame magnetic disposition. 

Take for instance, a 10 h. p. motor. Kow you do not want to 
imitate the steam turbine, but want to run at a decently low 
speed, say 900 revolutions. This will at 60 cycles per second 
give an eight, polar motor of very good magnetic design. But 
at 125 cycles, you have a 16 polar motor for 10 h. p. This and 
the excessive drop of potential in longer feeders, due to their 
self-induction, and probably also the high speed required in the 
generators, are the foremost reasons which make a reduction of 
the frequency desirable. 

In balancing all the advantages and disadvantages carefully, I 
found that 60 cycles per second will be about the all around best 
frequency for standard alternate current work. 

W ith regard to static transformers and the frequency effect, I 
have investigated and published a few things on this question 
before,* and liave shown that for a given size of transformer the 
output is in inverse proportion to the three-eighths power of the 
frequency, if the transformer is worked at its maximum output 
as aetermined by the heating of the transformer, that is, if the 
loss of energy in the transformer, which, as known, is the limit- 
ing factor of the output in a properly designed transformer, is 
kept the same. But then the efficiency for lower frequencies 
gets lower, and the magnetizing current larger, and if you take 
this into account, you will get as an approximation, that the out- 
put of a given transformer is about proportional to the square 
root of the frequency. 

But this rule only holds goods under the supposition that by 
reducing the frequency you can run the magnetization higher. 
Hence it holds only down to that frequency where the iron of 
the transformer approaches such a high saturation, that you can 
not decently run the magnetization hieher without getting a 
distortion of the wave of the electromotive force and an exces- 
sive magnetizing current. 

The progress aiade in the selection of the iron for transformer 
work, due to chemical analysis and careful testing of the iron 
for permeability and hysteresis, have made it possible to secure 
iron whose saturation curve makes a very sharp bend between 

1. Electrical Engineer, 1898. Electrical World, 1893. 

1894 ] DISCUSSION. 39 

14,000 and 16,000, so that you can run up to as higli a density as 
12,000 without fear of distortion or excessive magnetizing cur- 

This point of saturation of 12,000 is, as practical experience 
has shown, reached at 30 to 33 cycles, in larger units of trans- 
formers. Hence if you go still lower than that in the frequency, 
the output of the transformer decreases directly proportional to 
the decrease of the cycles, and the eflSciency decreases in the same 
proportion. That is, the transformer becomes very rapidly 
bulkier and it becomes impossible to build transformers of de- 
cent efficiency at any other but very large units. Probably in 
the future with the improvement in the production of good iron 
etc , this limit may go higher. Perhaps four years ago the limit 
was at lower frequency, because it was not possible then to 
secure the iron that we get now. As an instance, 1 may men- 
tion that while two years ago Ewing's value of the coefficient of 
hysteresis 5f = .002 was unrivaled, and the best Norway iron I 
could secure gave only tj = .(>023, now the standard transformer 
iron runs from r^ = .0020 up to j; = .0025, and is rejectc d if ^ 
is found to exceed .0025, while some time ago I accidentally even 
got a sample of iron whose hysteretic coefficient was as low as 
7j = .00124, 3S per cent, lower than Ewing's value. I did not 
believe this value at first, and had the test repeated three times, 
but with the same result. I have never got such iron again. 

With regard to another point that came up in the discussion, 
the behavior of incandescent lamps at various frequencies, I had 
occasion to make a set of tests some two years ago. 1 had an 
incandescent lamp fed by an alternator driven by a continuous 
current motor, whose field strength I varied to vary the fre- 
quency of the alternator, and varied its excitations to keep the 
potential the same, and I found that at 1 5 cycles and up to 20 
cycles the flickering was so abominable that "you could not look 
at the lamp without making your eyes ache. The brighter the 
lamp bums, the higher is the frequency where you notice the 
flickering. If you burn the lamp dull, at half intensity or so, 
then the flickenng is still unnoticeable at 25 cycles, but becomes 
noticeable just below this. But if you run the brightness of the 
light up to or beyond the normal o. p., then you notice the 
flickering plainly at 25 cycles, and it disappears only just below 
30 cycles. I did not make any tests with arc lamps, but since 
the temperature of the arc is considerably higher still than that of 
the incandescent lamp filament, probably the flickering is notice- 
able at still higher frequencies. Obviously the frequencies where 
flickering becomes noticeable, depend probably somewhat upon 
the personal equation of the observer. 

Mb. O. T. Crosby : — As there is considerable personal equa- 
tion in the matter of flickering I should like to learn if others 
were present and agreed with the speaker in his estimate as to 
the flickering ? 


Mb. Steinmetz: — I think the sensations of the gentlemen 
present at these tests agreed with me pretty well in that. Mr. 
Eickemeyer was there, and I believe Professor Forbes was there 
also, and some other men. 

With regard to the parallel running of alternators, that is 
quite an interesting point, because that has been brought up 
quite frequently as a disadvantage of the alternating system that 
alternators cannot run well in parallel. 

To settle this question 1 carried out a lengthy investigation, 
covering frequencies from 25 cycles up to 125 cycles, and alter- 
nators and three-phasers of very low armature self-induction, as 
smooth core machines with very few turns on the armature, and 
iron-clad armatures of high self-induction, and found in no case 
any diiBculty in parallel running, even under very extreme con- 
ditions, with properly designed alternators. 

Frequency and self-induction have directly nothing whatever 
to do with the ability of the alternators to run in parallel, and I 
found that it was a verv difficult matter indeed, if two alter- 
nators are running once m parallel, to make them drop out of 

Even equality of potential is by no means necessary in the 
machines which shall be synchronized, although desirable for 
equal distribution of load. 

It is known that Mordey has succeeded in running a 2,000 
volt and a 1,000 volt alternator in parallel. 

I went even a step further and took two 1,000-volt alternators, 
high frequency machines (since many people still share the 
superstition that high frequency machines do not run as well in 
parallel), excited one machine up to 2,000 volts and left the other 
machine unexcited, at zero volts, and then closed the synchroniz- 
ing switch, thereby throwing a 2,000 and a zero volt alternator 
into parallelism. Both macnines dropped into step directly and 
ran in synchronism at a potential of 1,075 volts at the bus bars.' 

In the notion that for successful parallel running self-induction 

1. It may be of interest here to give the results of a set of tests I made on 
the parallel running of iron-clad high-frequency alternators at very different 

Two 60 K. w. 1,000-volt alternators, iron-clad high-frequency machines of 
the General Electric Company's make running at their normal speed of 125 
cycles per second, were thrown in parallel at different excitations. 

Columns 1 and 2 give the electromotive force at the terminals of the two 
machines before synchronizing. 

Column 8 gives the difference between one and two, that is, the difference 
of electromotive force between the two machines in the moment of throwing 
them in parallel. 

Column 4 gives the voltage at the common terminals of the machines after 

Column 6, the cross current flowing between the machines. 

The machines fell into step and kept in synchronism without any difficulty 
even under these extreme conditions, except that in the case where the one 
machine was entirely unexcited, a certain fluctuation was noticeable in the re- 




is necessary, there is something true and something not true. 
The maximum synchronizing power will be exerted between the 
two alternators, if in the cross circuit formed by the armatures 
of the alternators, the resistance equals the ohmic inductance 
(not as it is frequently stated erroneously, if in the external cir- 
cuit this condition is fulfilled), but it is out of the question to 
use that, because if the inductance is so low as that, and you 
throw them together and they are not at absolutely the same 
phase, the synchronizing power will be so great, that they will 
probably be torn to pieces. But fortunately there exists no 
alternator that fulfills this condition, since in good alternators 
the armature inductauce is far in excess of the resistance. The 
larger the inductance, the weaker the synchronizing tendency, 
that is, the less you need to be careful to get the same phase and 
voltage in throwing them together. But you cannot in any way 
with any decent machine get such a large self-induction that they 
will not run in synchronism. 

With regard to the unbalancing of the three phase circuits I 
may refer to the paper I read before the Chicago Congress where 
I gave a mathematical investigation of this question, showing 
that according to the conditions of the circuit, the resistance and 
inductance, you can get it to zero or as high as you want or not 
want. The avoidance of the unbalancing of a three phase sys- 
tem depends entirely upon its proper design. 

With regard to the synchronous motor, I have very fully in- 

sultant voltage, which periodicaHy varied by 
approach to the limits of synchroiiizing power. 

± 70 volts, showing (he 



6o K. W. 125 CYCLES. 




M. p at the Common 
Terminals of Both .Ma- 
chines A f ter Synchroniz- 



xcess of Nf omentary Cur- 
rent at the instant of 
Synchronizing over the 













































x,6oo • 




















X.075 ± 70 



Full load curfent a 52,0 amperes. 


vestigated that also. Since I have bnilt quite a number of indue* 
tion motors and they are running successfully, nobody can say 
that I am prejudiced against the induction motor. But I believe 
and am fully convinced that wherever a synchronous motor can 
be used, it is a serious fault of engineering to use an induction 
motor, because the synchronous motor is so far superior to the 
induction motor, even with condensers, in the reaction upon the 
line and in the efficiency and the absolute constancy oi speed, 
that wherever the disadvantage of a lower starting torque is not 
of very serious consideration, especially for larger units, the only 
proper motor to be used is the synchronous motor, and only 
where a very large starting torque is required and, therefore, the 
synchronous motor cannot be used, or for smaller motors, where 
simplicity of construction and of handling is of foremost con- 
sideration, the use of induction motors is advisable. 

The condenser effect of the synchronous motor that Mr. Stan- 
ley spoke of is nothing new to me, nor probably to the members 
oi the iNSTiTUTE, because if you look back in the Transactions 
to the discussion of Mr. Kennelly's paper on impedance at the 
April meeting of last year, you will find the statement made by 
me in the discussion "That a synchronous motor at certain con- 
ditions of excitation acts like a condenser of very large capacity.'* 
That is all I think I can say at present. 

Dr. Bell:— Simply referring to something Mr. Stanley said; 
being in the back part of the room and being a little hoarse myself, 
I think he misunderstood the values which I gave for the power 
factor at light loads. I picked out a commercial case to illus- 
trate it. Supposing that, as Mr. Stanley stated, the load is some- 
where between thirty and forty per cent, of the rated load of 
the motor ; takings the three sizes of induction motors from 
which I gave the figures the average power factor at one-third 
load is just about 72 per cent., so that the case is by no means as 
bad as it might be supposed at first. The induction motors at 
very light loads have a bad power factor, even the best of them, 
when it comes down to extremely light load, one tenth, one- 
eighth, or something of that kind. Anywhere over quarter 
load they are really quite good as to power factor. 

I should say that 1 fully agree with Mr. Steinmetz that the 
synchronous motor is the advantageous thing to use when it can 
be used. As a matter of fact trie synchronous motors do not 
work so nicely in the small sizes as the big ones. 1 should say 
that for motors of 100 h. p. or above, it would in nearly every 
case be practical to use a synchronous motor, unless we come to 
railway work or something of that kind. Then we may have to 
use the induction motor in order to get the big tor/jue necessary. 
Most of the smaller work I believe will have to be done by 
the induction motors, and most of the larger work by the 

In respect to the question of frequency, it was perhaps suffici- 


ently discussed by Mr. Steinmetz. It simply falls in with my 
own experience, except that I rather confined it to the limits 
within which most of the transmission work will have to be 
done. That is, a little above that which enables yon to run in- 
candescent lamps, and below that it gets you into serious diffi- 
culty with induction. 

Mb. Staklby: — I think perhaps we are talking on a little 
different point with regard to frequency. My point was that 
with the same material in two motors designed for two fre- 
quencies the lag of current in the armature at low frequency 
must be greater than at high frequency. The power factor 
actually measured at the Pittstield station — the motor plant at 
the Pittsfield station, is 94 to 96 per cent., by actual tests, with 
the condensers in. 

Mr. C. O. Mailloux : — As we have here this evening many 
authorities on the subject of alternating currents, I think it 
would be well to have tlie facts brought out regarding the limit 
of voltage at present imposed where it is necessary to use cables. 
I quite understand that it may be possible to use very high 
voltages where the wires run overhead. But there are many 
cases involving or suggesting the use of alternating currents 
where it is, nevertheless, necessary to use cables. Now the ex- 
perience abroad has shown that they were not able to use suc- 
cessfully the extreme voltage which had been contemplated ; 
furthermore the question must be influenced, as was very clearly 
set forth by Dr. Bell, by the cost of the extra insulation and pre- 
cautions required for the rise in voltage. It all really comes 
back to the question of cost. It would be interesting to know 
what the extra cost is of the extra precautions, as the voltage is 
increased, and especially to know what at present is the commer- 
cial limit, so to speak of alternating currents used in under- 
ground cables, for two phase and three phase. I apprehend that 
for three phase the cost would be a little higher for the cable, 
because the mechanical difficulties of placing three conductors in 
one cable, if used concentrically, which I imagine would be best 
on account of its better elimination of the impedance ; and if 
there is any experience which has been had in this country at 
present, I think it would be very interesting to the fraternity to 
have the result of it. I have been given to understand, from 
having casually had occasion to look into the subject in connec- 
tion with a practical case, that about 2,000 vt»lts was as far as it 
was expedient to go at present in using underground cables. 

The President: — I will call on Mr. Frederick Darlington to 
make some remarks on this subject. 

Mr. Frederick Darlington : — If I understand the gentle- 
man's question, what he asks is the limitation of the conditions 
that you get when you go underground to the use of high volt- 
ages and high frequencies also. 

Mr. Mailloux: — Yes, frequencies also. 


Me. Daklinoton : — Dr. Bell touched on that question when 
he said in his paper that the eflEects most likely to trouble you 
were the resonance of the circuits and the capacity of the cir- 
cuits. I cannot give you any information based on practical ex- 
perience as far as very high voltages are concerned. I can say 
in reference to the cost of insulation that it is usually customary 
for various reasons, under practical conditions, in putting down 
a cable for say 1,000 volts, to have margin of safety enough to 
run two, three, four or tive thousand volts on the cable. One 
important reason for this (especially where you have aerial con- 
nection) is that if there is any possibility of lightning discharges 
on your line and you are working either 1,000 volts or 5,000 
volts you want to have sufficient insulation on the line to enable 
static discharges to be taken oflf safely. Except on very long 
lines you wilinot find the charge or discharge currents of cables 
enough to injuriously aifect the working of the system at 3,000 
volts or less at the ordinary frequencies — anything less than 130 
cycles. The matter of resonance I do not think will cut any 
figure at all at 3,000 volts or 5,000 volts, unless it may be, pos- 
sibly, on some very irregularly shaped current wave. The capacity 
of ordinary electric light and power cables varying in sizes from 
No. 3 and No. 4 B. & S. up to No. 0000 B. & S! is about one- 
third to one-half a microfarad per mile of conductor. When 
you are working a circuit you usually have two insulated con- 
ductors ; and this capacity given is the total capacity measured 
to earth for both conductors. Suppose you have four-tenths of a 
microfarad per mile as the capacity of your cable. The capacity 
of eich side of the circuit will be half the total capacity, as each 
side of the circuit contains but half the cable, and since you have 
two dielectrics in series, making two condensers each having half 
the capacity of the whole cable, the capacity between the con- 
ductors will be one-quarter of the total capacity of the cable in 
the circuit. If you have a little over two miles of circuit you 
have a little over four miles of conductor and that would give a 
capacity measured to earth of about two microfarads. Measured 
to earth for one conductor it would give a capacity of about one 
microfarad and give the capacity between conductors in actual 
working of one-half microfarad. That would make one- 
half microfarad capacity being charged and discharged all the 
time, and that gives for 1,000 volts on 135 cycles about one- 
half ampere charge and discharge current. It is evident that 
in the assumed case the static capacity does not make the false 
current in that circuit very great. If you are working on a cir- 
cuit with more or less retardation, the capacity may come in as an 
actual advantage by very nearly neutralizing the retardation. 
To sum up the commercial feature of it, 1 find that up to 
6,000 volts, using such cables as are readily obtainable in the 
market, you can buy any one of half-a-dozen good makes of 
cable that are safe for 5,000 volts. I do not find it economical 

1894.] DISCUSSION. 45 

OD l,000yolt circuits to use a thin insulation gach as would b& 
unsafe for 3,000 or 5.000 volts 

Mb. Stkinmetz : — First I want to say one or two words on this 
power factor. If jou use the same magnetic disposition you 
get the game powef factor and same torque, current and every- 
thing, whether you have a high or low frequency, i roper design 
supposed indeed. But by going down to lower frequency 
you are enabled to use a more favorable design. Consequently 
you can reduce the lag, increase the power factor and get a better 
eflSciency and better output per lbs. of weight; hence a low fre- 
quency is preferable — within certain limits indeed ; obviously 
nothing is gained, but much lost at least in weight efficiency,, 
and in flexibility, if you go down too far, for instance, below 30 

With regard to the cable, it is indeed true that in circuits 
with lagging current the capacity of the cable will, by taking a 
leading current, counteract and supply the lagging current in 
the circuit, so that occasionally more current comes out of the 
cable than is sent in. 

A simple analytical solution of the problem of a circuit con- 
taining distributed capacity, self-induction, resistance and leak- 
age, I nave given in my paper read before the Chicago Congress,, 
with curves showing tne periodical increase and decrease oi cur- 
rent and of electromotive force along the line. 

But I would rather prefer to keep the la^ and not introduce 
this very dangerous compensation, because this capacity is not 
only in shunt to the self-induction of the receiving circuit, but it 
is m series to the self induction between the capacity and the 
generator, and in the generator, and in this case, if capacity and 
self-induction are in series, as soon as they balance each other 
they annul each other and yon get a current as large as corre- 
sponds to the resistance only. Say you have a generator and a 
line which normally consumes 2 per cent, of the voltage. Then 
at open circuit, if the capacity of the line is just balanced by the 
self-induction, the curn'nt will increase to the value which it 
would have by short-circuiting the generator by the line with no 
self-induction, that is, to fifty times the normal value, and across 
the self-induction and across the capacity, that is, from line to 
line, you get the voltage corresponding to this abnormal current, 
that is, fifty times the normal voltage. That means resonance, 
and that means destruction. 

Usually you do not get resonance with the normal wave of cur- 
rent, but may quite likely get resonance with one of its higher 
harmonics, which is of lesser amplitude and, therefore, causes a 
lesser rise, but in high potential circuits, it may probably be high 
enough to destroy. 

Mr. Daklinoton : — In speaking of the results from capacity 
and resonance effects, I spoke more from experience than from 
theory, and th-^ conditions under which I have had experience- 


in opei*ating circuits underground have been very varied. In 
many instances I have put a very short underground circuit on a 
dynamo and had a small capacity in series with the self-induc- 
tion of the armatures. In other cases I have had a large static 
capacity made up fiom several underground circuits on one 
armature. 1 watched very carefully under both those circum- 
stances for any effect of resonance or rise of potential or any- 
thing that would tend to injure the cable and I have never seen 
it to any degree at all. 

Mb. btbinmbtz : — I may give you some data on an experiment 
I made some time ago, on resonance at very low potential and 
very low frequency. That was on a 100 volt alternating circuit 
of 25 cycles, where the line had a large self-induction, but small 
resistance. The line was feeding a bank of incandescent lamps, 
and across the terminals of the lighting circuit I put a con- 
denser or rather an apparatus that was equivalent to a condenser 
of about 7,000 microfarads. Then I found that with an electro- 
motive force of some 40 volts at the generator, at the end of the 
line I had something over 100 volts, when a current of 100 
amperes was passing. That was resonance. 

Dr. Bell : — I am inclined to think that resonance of the 
higher harmonics is the rule rather than the exception. I think 
there are comparatively few long lines of any kind where one is 
not likely to find a great deal more tendency to sparking and 
sputtering around the switchboard and on the line than would be 
accounted for by the normal voltage of the machine, even where 
the atmospheric conditions are not such as can account for it. 
There is quite frequently enough resonance to make it noticeable 
— a tendency to get some sort of abnormal quasi-static effect on 
a line of any considerable length. I am inclined to attribute it 
in many cases to the actual existence of this resonance mostly 
of higher harmonics of the e. m. f. 

Dr. M. 1. Pupin: — I have observed peculiar resonance effects 
on short lines — only about six feet in length, that is to say, the 
alternator was only about six feet from the transformer. They 
seem to me to bear on the matter of sparking on long lines. The 
resonance effects which I refer to, never occur when there is a 
big load on the transformer. It always occurs when there is no 
load at all, or a small load. It looks as if there was an oscilla- 
tion between the alternator and the transformer, which did not 
extend into the alternator or into the transformer. Of course 
on this short line containing a small coil without iron there was 
a condenser in shunt with the primary of the transformer. Now 
it is quite possible to have resonance on a long line when there 
is some distributed capacity there — and there always is — pro- 
vided the self-induction of the line be such as to give the length 
of the line the periodicity of some of the upper harmonics. 
The oscillation on the line may, and according to my investiga- 
tions, will occur extending into the motor, or into the trans- 

1894.1 DI8CU88I0N. 47 

former or into the alternator. It is entirely local. I have every 
reason to believe, although I have no conclusive proof as yet, 
tha- wnce this resonance effect, whenever it occurs, occurs always 
when there is a big self-induction in the transformer or motor, 
that it is due to some sort of a reflection ; that is to say, the high 
frequency wave belonging to some upper harmonics strikes, as 
it were, a solid wall when it encounters the large self-induction 
of the motor or transformer and is reflected back. These inter- 
ferences between the direct and the reflected waves may quite 
easily produce the sparking observed on long lines, especially 
when these long lines are worked by an impressed e. m. f. of 
several thousand volts.^ 

[Communicated aftee Adjournment by Chas. P. Steinmetz.] 

The analytical proof, tliat the frequency has no direct influ- 
ence upon the action of the polyphase induction motor, is the 
following : 

Leaving aside secondary phenomena, which can. be neglected 
in a properly designed motor, the maximum output which an in- 
duction motor can furnish is given by the equation : 

w- P^ 

where • 

jp = number of phases, 

E = electromotive force per phase, 

r = total effective resistance, 

u = total impedance of the motor circuit, per phase, that of 
the secondary circuit being reduced to the primary by the ratio 
of transformation.^ 

The impedance : 

u = V^ + (2 ;r i\^ Lf 


N = frequency, 

1 Dr. Bell calls this pheDomenon sputtering and not sparking. I have studied 
this phenomenon at some length and caUed it fiaky dincharge, because it con- 
sists of minute silent sparks looking like small snow flakes, which, when a 
large conducting surface is brought near the wire may take the form of a faint 
brush discharge. This brush discharge will take place even at considerable 
distance, so through half inch of fibre, hard rubber or dry wood, even if the 
potentials employed are only a little over a thousand volts, provided that the 
frequency is high enough, say over 800 periods per second. I intend to dis- 
cuss this phenomenon at some length in a paper which I am now preparing 
for the IifsTiTXJTB.— M. I. P. 

2. It may be mentioned here that this formula is the fundamental equation 
of the output of an alternating current circuit containing resistance and in- 
ductance (the latter being positive as magnetic inductance or negative as capa- 
city inductance, while the resistance is the * ' effective resistance in the sense 
as explained in my paper read before the Chicago Congress). It applies to the 
maximum output of transformers as well as of generators, synchronous motors, 
or the whole system in general. 


L =z coefficient of ^^-indnction (that is, coefficient referring^ 
to the magnetic flux interlinked with one, but not with the other 

Witn varying frequencies, if the same magnetic disposition ia 
maintained, the coefficient of self-induction L is inverse propor- 
tional to the frequency. 

Hence ^it N L^ and therefore u and TTare constant and in- 
dependent of the frequency. 

Thus the maximum output of an induction motor of given 
speed and size, and consequently its torque, is independent of the 
frequency, if the same magnetic disposition is maintained. 

The same holds lor the angle of lag of the motor, which at 
the moment of maximum output is given by 


hence is independent of the frequency also. 

In reality, as secondary phenomenon, a slight variation takes 
place with varying frequency, and r gets a fittle larger, and u 
a little smaller at low frequency ; that is, while the maximum 
output remains the same, the angle of W gets slightly less at 
lower cycles, and the power factor a little nigher consequently. 

However, if the same favorable magnetic design is maintained, 
at a frequency of from 70 to 80 cycles the peripheral speed of 
the motor becomes higher than is desirable for mecnanical reasons^ 
This is one of the reasons which induced me to recommend 60 
cycles as standard frequency for alternate current circuits for 
light and power distribution. 

Schenectady. N. V., February, 1894. 

The PREsroBNT : — If there is no further discussion I will call 
for the report of the Committee on Units and Standards. 


New York, Nov. 15th, 1893. 
To the President and Council^ of the 

American Institute of Electrical Engineers. 

Gentlemen: — Your committee on "Units and Standards" begs to 
recommend to the Institute the provisional adoption of : — 

The term •* gilbert'* for the c.o.s. unit of magnetomotive force, the 
same being produced by 0.7958 ampere-turn approximately. 

The term '*weber" for the c.g.s. magnetic unit of flux, sometimes 
described as the c.g.s. line of flux. 

The term '• oersted " for the c.g.s. unit of reluctance. 

The term "gauss " for the c.g.s. unit of flux density, or one weber per 
normal square centimetre. 

The committee, it will be remembered, in its previous report, dated 
June 20th, 1 891, advocated that the above terms should be accorded to 
magnitudes in conformity with the "practical" electromagnetic system, 

1894.] DISCUSSION. 4d 

and therefore following in natural order and extension from the volt, ohm^ 
ampere, and other units in universal use. 

As, however, so important a series of new unit magnitudes could only 
meet with general recognition and favor under the authorization of an 
International Electrical Congress, which authorization has been withheld at 
the recent Congress at Chicago, and since objections have been raised to 
those magnitudes, your committee considers that the urgent need for 
names specifying the principal quantities dealt with in magnetic circuits 
can best be met with general favor, by adopting for those names the 
fundamental unit magnitudes of the international c.g.s. system after the 
precedents already established in the cases of the c.g.s. units of force and 
work, entitled respectively the '* dyne " and '* erg." 

Yours very respectfully, 
Committee on Units and Standards. 

F. B. Crocker, 
W. E. Geyer, 

G. A. Hamilton, 

A. E. Kennelly, Chairman, 

Thb President: — Gentlemen, you have heard the report. 
What action will you take on it ? 

Mr. Townsend Wolcott: — It does not strike me that those 
names follow the precedents already established. The names of 
individuals are applied to c. q. s. units in no other case. 

Mb. Mailloux : — There is another fact which I think ouffht 
to be brought to the attention of the committee, and that is that 
the term " weber " is already preempted. That was done at 
the International Congress of 1881. I think there was some 
discussion as to the substitution of the word "amper^" for 
" weber " which was then the accepted term for the unit of cur- 
rent, and it was agreed, and, I think, entered on the record at 
the time, that the word " weber " should be used for the abso- 
lute unit of current which is 10 amperes, and, I think, the term 
is still in vogue or in force as the name for the absolute unit of 
current (10 amperes). Hence before we could appropriate that 
term for the unit of ma^etic flux it would be necessary to have 
some action rescinding its use for the unit of absolute current. 
The unit of absolute current is in reality seldom, if ever, referred 
to by name. It was a very good way to relegate that term to 
obscurity to use it for this unit, because we always speak of 
amperes and not tens of amperes or webers. At the same time, 
unfess the way is made clear by undoing the work of that con- 
gress, I think we shoald hesitate to make use of the term for 
another unit until we have a clear title to it. I have no objec- 
tion at all to the term " weber " for that purpose, if we can have 
the right to use it. 

Mb. Stbinmetz : — I do not consider the proposal of our com- 
mittee a happy one, and should not recommend the adoption of 
these new names, for the reason that, when we introduced the 
name " henry," we were aided greatly by the fact, that the name 


*' quadrant " proposed before, was not in conformity with the 
established system of denotation, which applies to the practical 
units the names of eminent scientists, and denotes the absolute 
units with Greek names. Here, now, we fall in the same error 
and propose the names of scientists, not for practical units, but 
for absolute units. Tlierefore I fear no congress would adopt 
these names since they do not agree with the established practi- 
cal units "ampere." '*ohm," etc. 

Furthermore, 1 really cannot see any urgent need for these 
new terms. For instance, the first one — *' gilbert " — the centi- 
metre-gramme unit of magnetomotive force will probably never 
be used in practice, because everybody calculates with ampere- 
turns, which is more convenient than (c. g. s.) units. As to the 
term " weber," you simply replace one name by another name, 
but the term 'Mine of force'' is generally used and cannot be 
mistaken for the practical unit, and it serves the purpose just as 
well. Then with regard to the term " gauss " you can just as 
well speak of lines of force, of kilolines or megalines. For 
" oersted " the term of magnetic reluctance, the same holds as 
for " gilbert." Reluctance is not generally used in engineering 

practice, and if it is used, it is applied to : : — . There- 

^ ' » rir ampere turns 

fore I should not recommend proposing such names, the more, 
as just after our success with tne name " henry," we ought to 
be very slow and careful not to lose the advantage that we gained 
by successfully introducing a new name, in proposing without 
full consideration and investigation new names, which have 
little, if any, chance to be adopted finally, and should rather 
leave the matter as it stands c. o. s. units, lines, kilolines, and 

Mr. a. E. Kennblly: — What Mr. Steinmetz has said in re- 
gard to the absence of occasion for the use of the quantities 
now under consideration for names, has been up to the present 
time unfortunately only too true ; for the reason that we have 
not had names to call them by. That has been the experience 
not only in the magnetic system but also in the preceding elec- 
tric system, that there was no active general development of the 
ideas connected with the quantities of each science until we had 
names upon which to build those ideas. It is only when we are 
able to express our thoughts in clear, simple terms, and only 
when we possess such terms that these ideas can extend and 
generalize. If we did not have the names " volt," "ohm," and 
" ampere," we should not have electrical science and arts in the 
condition they are in to-day. There is surely a very urgent need 
for names of some kind in connection with a magnetic circuit, 
because we are constantly seeing the strenuous efforts people now 
make to avoid expressing their ideas relating to magnetic cir- 
cuits in a quantitative manner. If I take up this book in my 
hand and want to express the weight of it, isn't it far better to 

1894.J DISCUSSION. 51 

jsay, this book weighs three hundred grammes, than three hun- 
dred units of weight in the c. g. s. system. Contrast the concise- 
ness and deiiniteness of these two statements. 

In regard to the objection as to names taken from eminent 
electricians or names taken from Greek roots, it is true we have 
not a sufficient number of ^eat Greek electricians upon whom 
we can fall back for suitable names. If any one will suggest 
suitable Greek names that are likely to meet with support and 
favor, I am sure we would only be too pleased to hear them. 
But as we do not possess the facility for creating Greek names 
in this country that will meet with general apprehension and 
support, how can we do better than select these well known and 
honored names that have been such stars on the pathway of the 
development of this science. Surely there can be no question 
concerning the relative advantages oi Greek derivations that not 
one speaker in a hundred might understand, compared with such 
names as those we advocate, which are household words among 
us all. We cannot at the present time expect to create new unit 
magnitudes. That is the province of an international electrical 
congress. But we can, without inflicting any disadvantage 
upon our neighbors, provisionally adopt names of this kind for 
units already established by electrical congresses — the c. o. s. 
units that we constantly employ— and we believe that by so do- 
ing, we can greatly aid the science and art of electrical engi- 

Mb. Mailloux : — It seems to me that the objection might be 
to some extent obviated by regarding these terms as applying to 
practical units instead of o. g. s. units. They might, if we chose, 
be looked upon as being coincident with tne c. g. s. value. At 
the same time in calling them practical units we would not be 
departing from the established precedent in that respect. We 
have a perfect right to confer such names as these on practical 
units. I think myself that the objection against invading the 
prerogatives of pure science is somewhat valid. I think that 
there is a tendency, in our science especially, to a certain jum- 
bling of terms by not giving careful attention to what might be 
called the "proprieties" of lexicography, and I think that cer- 
tainly it would be a step which would command the approval of 
a greater proportion of the members and of scientific men gen- 
erally, to consider these things as practical units, rather than as 
c. G. 8. units, even though they might have the same value. For 
instance, it was a mere accident that we were using one ampere, 
and that we gave it a special name which was one-tenth the 
value of the absolute electro-magnetic unit of current. In the 
case of the proposed new units it may be a coincidence that we 
happen to use the same value as the absolute unit for the practi- 
cal unit. 

Another point that I would like to call attention to, is the fact 
that the expression .7958 ampere-turn is a very awkward one to 
handle. Tnat is one objection in fact to tne adoption of the 


term " gilbert " as now defined by the committee. It would not 
be used probably as much as the term ampere-turns to which we 
are now accustomed, for the reason that tne conversion involyes 
a rather awkward fraction. There is also a more or less definite 
objection to the use of any term for reluctance, because the 
term reluctance itself does not express any concrete value unless 
we take into consideration the particular facts and circumstances 
surrounding the particular case. 

Thb Pbesidbnt: — What action will you take on this report, 
gentlemen ? 

Mb. C. S. Bradley :— There seem to be two objectors and 
there were four members of the committee. I think the 
majority is in favor of the report. I move that it be provision- 
ally adopted. [Seconded.] 

Mr. Mailloux : — I move that the matter be laid on the table. 

[The motion was seconded and carried.] 

The President : — I call for the report of the Committee on 
Eevision of the Eules — Dr. Herzog, Chairman. 

The Secretary : — This report was handed in by the Chair- 
man, Dr. Herzog, who could not remain to present in person. 

The President: — It contains a notice of certain proposed 
changes in the by-laws. The Secretary will please read it. 

The Secretary read the following report : 


At a meetins: of the Committee, duly held, it was unanimously resolved 
to advise that the rules relating to elections be immediately changed as set 
forth below. 

In pursuance of this resolution and of the provision in Section VIII., 
controlling the manner in which amendments may be made, the prescribed 
written notice is hereby given by the Chairman on behalf of the Com- 

At the next or at some subsequent regular meeting of the Institute the 
following separate amendments of the rules will be brought up : 

Resolved, that Section V. be amended as follows : 

ist change — After " a " in line 13, add the words ** second list headed." 

2d change — Line 18, after "choice" add "opposite the name of each 
nominee in each list shall be printed a number indicating the number of 
nominations received by him, and a suitable explanation of these numerals 
shall be placed on the sheet." 

3d change — Lines 33 to 36, shall be changed to read " sealed, unmarked 
and unidentified * Inner envelope ' of any suitable character, to be in its 
turn enclosed either in the * Voting envelope ' (received from the Secre- 
tary) or in any other envelope marked on its face * Non-official Voting En- 
velope-Enclosing a ballot only.* The outer envelope of either class must 
be identified by the signature of the member on its face, and must be sealed 
and mailed to the Secretary." 

Respectfully submitted, 

[ F. Benedict Herzog, Chairman. 
Jan. 17, 1893. Signed, j T. C. Martin. 

' F. R. Upton, Assenting. 


New York, February 21, 1894. 

The eighty-fourth meetinff of the Institute was held this date, 
at 12 West Slat street, and was called to order by President 
Houston at 8 p. m. 

The Secretary read the minutes of the last meeting and on 
motion they were approved. 

The Secretary read the following list of associate members 
elected, and of associate members transferred to full membership 
at the Conncil meeting held February 21st. 


Babcock, Clifford D., 

Barstow, William S., 
Clough, Albert L., 
Crosby, James W., 
Forbes, George. 
Frantzbn, Arthur 

Oerry, Edward M., 
Oesseaumb, Charles 
Harrison, Harold 

Address. Endorsed by. 

203 East 87th Street, Chas. A. Doremus. 

New York City. Wm. J. Jcnks. 
L. Stieringer. 

General Supt., Edison Electric Chas. Hewitt. 

Illuminating Co., 360 Pearl St., James Hamblet. 
Brooklyn, N. Y. J. P. Wintringham. 

Box 114. Manchester, N. H. 

Electrical Engineer. 

Hix, Crosby & Co., 

128 Broadway. 
Electrical Engineer, 

34 Great George St., 

London, England. Horatio A. Foster. 

Inspector, Electrical Engineering R. H. Pierce. 

Dept., World's Columbian Ex- Lemuel S. Boggs. 

position, 662 Shober St. Chicago, G. Sacco Albanese. 


Wm. L. Puflfcr. 

Geo F. Curtiss. 

Caryl D Haskins. 

Wm. J. Hammer. 

Joseph Wetzler. 

Wm. J. Jenks. 

T. C. Martin. 

Joseph Wetzler. 

Weston Electrical Instrument Co., 
114 William St., 

Newark, N. J. 
Chief Draughtsman, Newark 
Factory, Westing house Electric 
and Mfg. Co., Newark, N. J. 
New York Representative, 
Slater Engine Co., 

Montclair, N. J. 

James Hamblet. 
R O. Heinrich. 
Edward Weston. 

L. A. Osborne. 
Philip A. Lange. 
F. N. Waterman. 

Wm. E. Geyer. 
F. A. Pickemell. 
James H. Bates. 


Hix, E. Randolph 
LiGHTHirK, James A., 
Morehouse, H. H., 

Potts, Chas. Edwin 
Richardson, Albert E. 


Snook, S. D., 
Trafford, E. W. 
Treadwell, Augustus, Jr, 
Wendle, George E., 
Total 19. 

Hix, Crosby & Co., Electrical 
Engineers and Contractors, 128 
Broadway, New York City. 

District Engineer, General Elec- 
tric Co., 15 First Street. San 
Francisco, Cal. 

General Manager and Electrician, 
Alumbrado Eiectrice de Quezalte- 
nango, Apartado.Quezaltenango. 
Guatemala, C. A. 

Student in Electricity, 

1248 Dean Street, 

Brooklyn, N. Y. 

Lecturer in Science, County of 
Surrey, 55 Coleridge Road, 
Crouch End, London, Eng. 

Post-Graduate Student, Columbia 
College, 247 W. 138th Street, 
New York City. 

Manager. Williamsburg Exchange, 
N.Y. and N. J. Telephone Co.. 
14 BoerumSt., Brooklyn. N.Y. 

Electrical Engineer, Richmond 
Railway and Electric Co,, 104 
N. 7th St., Richmond, Va. 
., Private Assistant. Polytechnic 
Institute, 448 3d St. , Brooklyn, 
N. Y. 

Instructor in Electrical Engineer- 
ing, Lehigh University, 705 
Dakota St., So. Bethlehem, Pa. 

Wm. J. Hammer 

Jos. Wetzler. 

Wm. J. Jenks. 

F. F. Barbour. 

Louis Bell. 

Elihu Thomson. 

C. O. Mailloux. 

H. A. Sinclair. 

Jos. Wetzler. 

Samuel Sheldon. 

O. R. Roberson. 

James Hamblet. 

R. W. Pope. 

T. C. Martin. 

Jos. Wet/ler. 

M. I. Pupin. 

F. B. Crocker. 

W. H. Freedman. 

W. D. Sargent. 

J. C. Reilly. 

R. W. Pope. 

A. M. Schocn. 

C. E. McCluer. 

M. B. Leonard. 

Samuel Sheldon. 

Chas. Hewitt. 

G. W. Gardanier. 

E. J. Houston. 

F. B. Crocker. 

R. W. Pope. 


Approved by Board of Examiners, December 7th, 1893. 

Electrician, New York and Pennsylvania Telephone 
■ - * " ^ ~ 1, N. Y. 

WoLVERTON, Byron C. 

and Telegraph Ca, Elmira, 
Van Trump, C. Reginald Engineer and Manager, Wilmington City Electric 

Co., Wilmington, Del. 
General Manager New York and New Jersey Tele- 
phone Co., Brooklyn, N. Y. 
Assistant Electrical Engineer, Buffalo Railway Co., 

Buffalo, N. Y. 
Electrical Engineer, General Electric Co., Boston, 

Sargent, Wm. D. 
GiFFORD, Clarence E. 
LovEjoY, Jesse R. 
Total 5. 

The Pbesident : — The next order of business will be the re" 
port of the Committee on Revision of the Rules governing 
Elections. Is it your desire to take this up now, or after the 
paper? If there is no desire expressed, the Cliair will decide to 
take it up after the paper. 

I believe there is also a report of the Committee on Units and 
Standards, Mr. Kennelly Chairman. 


Mr. Kennelly : — I beg, sir, to give notice of a motion to be 
made at the next meeting of the Institute, that the report of the 
committee be taken from the table at that time. 

The President : — It has been suggested that Mr. Maaro will 
read a paper concerning a Change of Policy in the Administra- 
of the Patent OflSce, prior to Mr. Leonard's paper, as Mr. 
Leonard's paper will be illustrated by experiments. I take pleasure 
in introdncing to you Mr. Philip Mauro, of Washington. 

Mr. Mauro: — Mr. President and Gentlemen. It may not be 
amiss, I hope, before coming directly to my theme, to express the 
gratification! feel in meeting for the first time, my fellow mem- 
bers of this Institute. Although, as I say, this is the first time 
I have enjoyed that pleasure, I have, nevertheless, through the 
medium of your transactions noted with a great deal of satisfac- 
tion the progress of your body in keeping pace with the marvel- 
lous advance in the branch of human activity to which most of 
your members are devoted. 

I understand that the rules and practices governing your 
procedure here, permit the author of a paper, which has presum- 
ably been read and to some extent digested in advance, to present 
briefly the points and propositions that he desires to advance, in 
order to leave larger time for discussion. I shall the more gladly 
avail myself of this privilege, because, there is another paper to 
be submitted, which will probably be of more interest to the 
body than the paper I present, and because I am particularly 
interested in having those persons who are concerned with the 
subject that brings me here this evening, express their views in 
the fullest manner. 

[Mr. Mauro's paper appears in full on the following pages.] 

A paper prtsetUtd at the 84ih mttting of the 
Americam iMsiiiMtt of EUctrical Engineers^ 
New VerJkf February g/st^ 1894. President 
Houston in the Chair. 



The viewB presented in these pages were called forth by the 
announcement or rumor that the present Commissioner of 
Patents had decided to inaugurate a radical change of policy in 
his office, in the treatment of applications for patents where the 
margin of novelty is small, or the exercise of invention doubtful. 
The old rule, unwritten but tacitly recognized, has been ; when a 
substantial doubt exists to give the applicant the benefit of it. 
This rule, it is said, has been reversed. 

The policy and purposes of the head of this important bureau 
are matters of deep interest to the public in general, and partic- 
ularly to the industrial portion thereof ; and while the present 
incumbent has not seen fit to make any public declaration of his 
policy in the treatment of applications, the impression that very 
generally exists, to the effect that radical changes are in contem- 
plation, furnishes a suitable occasion for examining and consider- 
ing the relations of the Patent Oflice to the industrial arts, and 
the influence it exercises upon the development of the country's 
resources. It is the natural desire of every citizen to see that 
influence increased, and the affairs of the Patent Office so admin- 
istered as to produce the greatest possible benefit to the public. 
It may, therefore, be taken for granted that any changes which 
the Commissioner of Patents may contemplate in the adminis- 
tration of his oflBce, will have that object in view ; but the conse- 
quences of changes of this sort c^n never be wholly foreseen, and 
frequently are of a nature quite unexpected. 

This is my excuse for putting before the Institute of Eleo- 


TRiOAL Engineers ray views as to the probable consequences of 
«uch change of policy in the Patent Office as is supposed now to 
be going into effect. 

The particular point of inquiry is, whether the examining 
-corps of the Patent Office has been so lavish, lax and imprudent 
in the issue of patents, particularly where the novel improve- 
ment sought to be covered was of a trifling character, that the 
public interests have been detrimentally affected. If so, what 
are the particular evils that have resulted from this undue libe- 
rality, and how far should the Patent Office shift its ground in 
the other direction in order to avoid them ? 

Upon the mere statement of these questions it is apparent that 
they will not be easy to answer in a conclusive and satisfactory 
manner ; yet it is my hope and belief that, after a fair considera- 
tion of them, the conclusions will be that there is no ground 
whatever for apprehension of damage to the public or to indi- 
viduals by reason of undue liberality on the part of the patent 
examiners, but that, on the contrary, the only damage that has 
been, or will be caused, proceeds from those members of the 
corps who by nature and habit are disposed to take the narrow 
-and illiberal view of inventions. 

In so large a body of men as the examining corps, there is, of 
course, great diversity of character, disposition, and mode of 
action. In the exercise of judgment upon applications for 
patents, we find the two extremes of undue liberality on the one 
hand, and excessive strictness on the other, and this will always 
be so; but no one competent to judge will deny that, up to the 
present time, the work of the bureau as a whole has been 
characterized by fairness, just discrimination, and due apprecia- 
tion of the rights of inventors, with a leaning rather in the 
<Jirection of the more illiberal and narrow decisions which have 
in recent years emanated from judges of small experience in 
patent matters, and of slight acquaintance with the actual steps 
of the process whereby the development of the useful arts is 
effected. The patent system of the United States owes its 
present position of usefulness and importance to the happy cir- 
cumstance that its principles received their first interpretation, 
and its purpose their first judicial declaration, from broad-minded 
and far-seeing men ; and so long as the development of the sys- 
tem follows the impetus and direction given it by the earlier 
decisions of the Federal courts, its beneficent influence upon 
national prosperity will extend on every side. 


Uniese the actions of the examining corps as a wliole have 
been lax, careless, and unduly liberal (which certainly is not the 
case), it is clear that the sum of all the effects of a change in the 
direction of greater stringency must be detrimental and injurious. 
The easy-going and indulgent examiner (how many such are 
there ?) may be restrained from improvident grants, but the man 
of fair mind and sound judgment will feel impelled to refuse 
patents which, in the untrammelled exercise of his discretion, he 
would ordinarily allow ; while the strict constructionist, whose 
dominant motive appears to be hostility to inventors, will be 
confirmed and encouraged in his disposition to perceive an antag- 
onist in every applicant for a patent, and to dispute and place 
obstacles in the way of every claim that is submitted for 

The proposition at this point is simply that the policy of the 
Patent Office as a whole in the treatment of applications has not 
heretofore been liberal to the point of laxity or improvidence. 
The only basis that I am aware of for any opinion to the contrary, 
is the fact that many patents have been held by the courts to be 
void or illegal grants, on the ground that the subject-matter was 
not patentable, or did not in view of the evidence and character 
of the results achieved, rise to the dignity of an invention, or in- 
volved merely the exercise of mechanical skill. But it would be 
hasty and illogical to conclude from this fact that the Patent 
Office has been too liberal in deciding upon applications, and that 
it would be proper to inaugurate a less liberal policy. In the first 
place, assuming (which is rarely the case) that the court in annul- 
ling the patent has before it the same evidence upon which the 
decision of the examiner was made, we venture to assert that, in 
the large majority of such cases, the examiner was right and the 
court wrong. Without disparaging the qualifications of judges, 
appointed to the bench for their learning and experience in other 
branches of the law, to deal with what has been aptly termed the 
metaphysics of the science, we would maintain with great confi- 
dence that the majority of the examining corps are better qualified 
by experience and educated judgment to pass upon the patenta- 
bility of inventions than the average Federal judge. 

That this is not a rash or ill-considered statement must be evi- 
dent upon refiection. The patent examiners, as a rule, are men 
of scientific attainments, many having enjoyed in addition a 
legal education. Each one has been devoted, for a longer or 


shorter time, to the study of a particular art or class of invention, 
and in the course of each day makes more decisions upon ques- 
tions of patentability than will ordinarily be presented to any one 
judge in the course of a year. On the other hand, the judiciary 
18 composed almost entirely of lawyers who before their eleva- 
tion to the bench, if charged with similar patent cases to those 
they are then called upon to decide, would have considered them 
selves incompetent to conduct or argue them, and have been 
obliged to employ a specialist in that branch of the law. 

Furthermore, it must be remembered that we are not now 
considering decisions that expound the meaning of the statutes 
or declare legal principles, as to which, the voice of the court is 
the only authority that can be recognized. The question whether, 
in view of the state of the prior art, a given improvement was 
an inventive act, or differed from mere mechanical skill, is a 
question of fa<;t^ which in all trials at law, is decided by the 
twelve men whom the chance of lot may have placed in the jury 
box. In the nature of things, a decision that a particular me- 
chanical expedient or departure did not involve invention, can 
have little or no effect or value beyond the settling of the ques- 
tion for that particular case. For example, the decision that to 
put a rubber tip on the end of a lead pencil did not involve in- 
vention, or produce a patentable article (Reckendorfer v. Faber, 
92, U. S.) gives no aid in determining whether it was an inven- 
tive act to put a torsional spring on a telegraph sounder, there to 
behave in the manner usual with torsional springs. If the first 
case has any bearing upon the second, it would, of course, lead 
to the conclusion that the latter involved no patentable change. 
Yet the Supreme Court held otherwise (Western Electric Co., v. 
La Rue, 139, U. S.). 

Finally I would ask those who desire to find and follow court 
precedent in the class of cases now under consideration, to re- 
member that patents, involving changes apparently as slight as 
any that ever issued from the Patent OflSce, have been sustained 
by courts and judges of the highest reputation and authority, so 
that, if precedent be sought, it can be found in abundance and 
to the liking of the seeker. The example given above is a suffi- 
cient illustratiou. 

In drawing deductions from decided cases, however, it should, 
in justice both to the judges and to the examiners be said that in 
the case of most of the patents which have been found invalid by 


the former, new evidence not accessible to, or perhaps overlooked 
by the latter,- has been presented ; so that in but a small number 
of cases can it be said that the decision of the examiner has been 
reversed by the court. The [conclusion, therefore, is that 
decisions of this sort constitute no reflection upon the work or 
judgment of the Patent Office and no justification for any change 
of policy in the direction indicated. 

But admitting the full force of the fact that certain examiners, 
in certain instances, have erred on the side of excess of liberality, 
what are the consequent evils ds compeared with those of errors 
in tlie other direction ? The grant of a patent is, in ninety-nine 
cases out of a hundred, an act without any consequences what- 
ever. But so potent for good is the hundredth invention — ^the 
one that contains the germ of vitality and usefulness — to such 
an extent does it stimulate the exertions of other inventors that it 
more than pays for all the failures. The chances, then, of issu- 
ing one patent too many, are infinitely small as compared with 
the chances of prematurely stifling and suppressing what might 
be productive of benefit ; so that the greatest care in conducting 
the work of the Patent Office is needed to guard against actions 
which both work injustice to meritorious inventors, and at the 
same time injure the public by depriving them of the advantage 
which inevitably accrues from the grant of a patent for a useful 
novelty, however trivial. 

As to the ultimate career of an invention, the judgment of the 
most experienced persons is ordinarily worthless. Frequently it 
is the things that promised least, from which the best results have 
followed, and vice versa. It appears strange at first, and yet en- 
tirely explicable upon reflection, that the novelties which contain 
the greatest amount of "invention" and ingenuity are often of 
the least practical benefit. Machines which are marvelous pro- 
ducts of inventive skill, and full of the most intricate and com- 
plex mechanism, for which a patent will be granted with 
enthusiasm, become frequently but curious exhibits of misdirected 
inventive imagination; while on the other hand the inventor 
who aims to effect but a slight departure or simplification of 
what already exists \& the one who really benefits himself and the 
community. It is by the accumulation of small changes of this 
nature that the industrial arts advance, step by step, in ever-in- 
creasing usefulness. 

It is in partial appreciation and recognition of this fact that the 


accepted policy of the Patent Office has heretofore been to give 
the inventor the benefit of the doubt in marginal and doubtful 
cases. Experience shows this to be the safe and wise policy. 
The examiner who knows something of the history of patentable 
inventions will, in cases like this, be influenced by the considera- 
tion that the resvlts of the grant alone can determine whether 
the device in question has the quality of invention or not ; that 
if it have that quality the inventor deserves his patent, and that 
if it lacks it, no material harm can result from its grant. He 
will also be influenced by the consideration that the grant confers 
after all only a pri/ma facie right ; and in proportion as the courts 
are the more ready to try anew, without regard to the decision 
of the examiner, the question of patentability, the more freely 
will the latter exercise his discretion in doubtful cases. 

But we have of late heard the reverse of this policy termed 
" giving the benefit of the doubt to the publicP This expres- 
sion thinly conceals the fallacious idea that, in rejecting a patent 
for a new but slight improvement, it is thereby given to the 
public. Nothing could be more delusive or contrary to actual 
experience. It is the grant of the patent, not its refusal^ that 
gives the invention, great or small, to the public ; and even the 
grant is but a step in that direction. After that, it requires the 
utmost persistence, the most favorable conditions, the enlistment 
of capital and enterprise, to make the blind and heedless public 
see that the change will be beneficial, and to force the stolid and 
reluctant public to adopt it. The notion that an improvement 
comes into possession of the public when the discriminating ex- 
aminer had decided that it is too trivial for a patent, is one that 
cannot exist in any mind after a most superficial consideration of 
the facts. The very contrary is the case, namely, that the most 
effectual way to prevent its ever coming into the possession of 
the public is to thwart the inventor's efforts to secure a patent 
for it. 

Take any case of actual occurrence that will illustrate the 
point, as, for example, Butler v. Steckel (137 U. S., 21), which 
involved an improvement consisting simply in producing, by 
mAtchinery^ a bretzel having the appearance of a hand-made 
bretzel. For some reason, there is a prejudice on the part of 
those who are partial to that delicacy, in favor of the looks of a 
hand-made bretzel ; and the inventor in this case had the idea of 
satisfying that prejudice and yet effecting the great economy of 


machine production. The Supreme Court, which has also judici- 
ally decided (McLean v. Ortmayer, 141 U. S., 419), that *' inven- 
tion " can7wt he defined so as to determine in any given case 
whether the " inventive faculty '' has been exercised or not, de- 
cided that there was no '* invention " in making a mould to 
produce an apparently hand-made bretzel. 

We may assume that the Supreme Court, while not knowing 
what " the inventive faculty is," but indeed declaring it to be 
unknowable, yet is gifted with some means of knowing when it 
has been exercised, and was right in this case, and consequently 
that the examiner who granted the patent was wrong. The 
question that concerns us is, what consequences resulted from liis 
action in granting the patent i It is easy to see that the results 
of this error of judgment, if it were one, were distinctly bene- 
ficial. The grant and publication of the patent made the im- 
provement known, and stimulated the patentee and his associates 
to introduce it to the public and demonstrate its merits. These 
were recognized, so far as to encourage others to take up the 
manufacture, thus accomplishing the great purpose of the patent 
law in spreading the benefits of the improvement, and inciden- 
tally bringing about a suit for infringement. Then, the case com- 
ing before the Supreme Court for application of the divining 
rod, or intuitive faculty, or whatever means that august tribunal 
employs to detect the presence or absence of '' invention," the 
subtle quality was not perceived, the patent was declared void, 
and the whole matter — fully develo])ed to the manufacturing 
stage, thanks to the examiner — was thrown into the public do- 

This is, and must be, the result in every similar case ; and it is 
quite safe to say that if the examiner had assumed to pronounce 
that the "inventive faculty" had not been exercised in this mat- 
ter, the public would never have known anything about it, and a 
useful idea, even if not a patentable one in the opinion of the 
judges who decided the case, would have been strangled in its 

If, therefore, the judges have sometimes differed from the ex- 
aminers as to what constitutes a patentable invention, I can see 
in that, no reason for hesitation in the granting of patents for 
fear the courts may find an occasion for such difference of opinion. 
The chances are that the judges were mistaken in many of these 
cases ; and if they have corrected errors in others, they have sim- 


ply discharged one of the purposes for which courts are estab- 
lished, and were certainly, with the evidence on both sides before 
them, in a better position to pass the final judgment than the 
examiner could be. 

Let the Patent Office, then, pursue its course courageously, 
leaving to the courts their proper functions, and not risking, in 
the attempt to avoid a harmless error, the perpetration of a cruel 
injustice to the individual and a serious damage to the public. 

Why refuse a patent because the invention is a " little" one? 
Why take away from the humble inventor his small invention 
on the ground that it is so trivial that the public ought to have it 
gratis, especially when it is thereby buried in the musty pigeon- 
holes of the Patent Office beyond the influence even of the res- 
urrection trump ? Why not give him the " little " patent that 
he seeks for his " little " invention, and encourage him to cultivate 
and tend and promote his idea, on the chance that it may be 
nurtured into something useful to mankind, even in a "small ' 
degree ? The Patent Office need not fear the consequences of 
making a mistake in so doing, for there is every ground for 
assurance, that if the inventor succeeds commercially, the court 
will be ready enough to take away his patent if the invention has 
not the magnitude to bring it within the mental perception of the 
judge who tries the case. 

After all, the patent has but the dimensions of the invention 
which it covers. If they be limited, the patent is correspondingly 
narrow. Therefore, the Commissioner and his examiners are not 
called upon to exercise the same discrimination as if a patent 
were an award or premium of definite value, only to be granted 
when an invention is found to posses a certain degree of 

But I cannot turn from the discussion of the relations between 
the courts and the Patent Office, without briefly referring to the 
other side of the subject, and endeavoring to point out where 
the real damage has been inflicted, and where the real danger lies. 

The trend of judicial decisions furnishes no occasion to narrow 
the field of patentable invention and of inventive enterprise. On 
the other hand, there is every reason to broaden the spirit in 
which the laws are administered in the Patent Office. 

The wrong that has been done in adherence to the policy of 
trimming down each patent to the narrowest dimensions, is incal- 
culable. The courts, while ever ready to restrict patents by the 


state of the prior art, never broaden them by interpretation be- 
yond the language of the claims, which bind the patentee, but not 
the infringer, nor anyone else. There was a time when correction 
of mistakes by enlargement of claims unduly limited, was per- 
mitted through reissue of the patent on the payment of another 
tax, and when the refusal of this privilege, even without an 
express statute, was denounced by the great Chief-Justice 
Marshall as an act that would be '* disreputable in an individual " 
and which " a court of equity might interpose to restrain " (Grant 
V. Raymond, 6 Peters). But the " courts of equity " have since 
swept that privilege away, and the inventor's only chance now is,, 
with perhaps incompetent solicitors, and in the face of an alert 
and often hostile examiner, to secure claims sufficiently broad in 
the first instance. 

If we ask where a material injury has been done by an excess, 
of liberality in the decision of an examiner, it would be difficult 
to find an instance. If we ask in how many cases have patents; 
for meritorious inventions failed, because of the persistent and. 
successful efforts of examiners to narrow the terms of the 
claims, it would be impossible to determine the enormous total. 

The catalogue of the reissue decisions contains the history of 
grievous wrongs and injustice, due in many instances to the in- 
ability of the inventor, through lack of means or of competent 
solicitors, to combat successfully the opposition of an examiner. 

The grant of a patent to an applicant for more, or other than 
he can sustain before the courts profits him nothing, and deprive8> 
the community of no right. The failure of any inventor, who^ 
has communicated to the public his discovery, of whatever magni- 
tude, to secure a grant to the full extent of his right, is occasion 
for profound concern, against which the officials of the Patent 
Bureau should be constantly on the alert. This part of an ex- 
aminer's duty we have reason to think, is one that sits lightly 
upon his mind; and the exercise of official vigilance to which we* 
are most accustomed has quite a different motive and object. 
Theoretically, the obligation above referred to is uniformly rec- 
ognized. Practically, the examiner's duty is usually discharged 
to his entire satisfaction when he has made a rejection. 

If, by the exercise of unusual watchfulness and careful scru- 
tiny, the issue of a few hundred worthless patents be arrested, the- 
result may be creditable to the administration, but can hardly be 
regarded with satisfaction for any practical benefit accomplished.. 


The discovery and remedy of a single case of injustice, where 
the inventor has paid, perhaps, his last dollar for the preliminary 
fees, and is helpless to contest the too ready letter of rejection, 
would afford, to my mind, a far better basis for a claim upon 
public gratitude ; and who can dispute that the opportunities for 
the head of the Patent Office, are much richer in this direction 
than in the other ? 

I have noted with much concern the growing disposition of 
the patent examiners to follow the lead of some of the Federal 
judges in rejecting applications, where novelty was conceded, 
on the ground that there was *' no invention in doing this in 
view of that," or as sometimes expressed, because the matter 
" does not involve the exercise of the inventive faculty." This 
tendency has developed quite recently to an alarming extent, and 
being a serious matter, which hitherto has received but scant 
attention on the part of those whose interests are involved, it 
may not be amiss to devote a brief time to its consideration. 

If, in addition to the exhaustive and fatiguing labors of novelty 
searches, the thirty-six examiners are to determine, in the caae of 
every novelty submitted to them, whether the new thing specifi- 
cally pointed out and distinctly claimed, is an " invention " or 
not, it is manifestly necessary that they should be provided with 
a clear and comprehensive definition of what an " invention " is, 
and that each and every examiner should recognize the same 
definition. The authorities do not, and confessedly cannot, fur- 
nish such a definition. Professor Robinson (than whom there is 
probably no person more competent to frame the needed defini- 
tion in words) in his exhaustive work on patents, defines inven- 
tion '^ as the result of an inventive act," which does not assist 
me personally to a conclusion which I much desire to reach. 
The Supreme Court, as we have seen, declares that invention is 
indefinable, and surely it is not profitable to search further. 

We all know, moreover, if we have reflected at all on the 
subject, that whether the "inventive faculty" has been exer- 
cised in any case, is a question that lies outside the perceptive 
faculties and beyond the investigation of the reasoning powers 
of mankind. Now the law manifestly did not intend to charge 
the Commissioner of Patents with the duty of granting an ex- 
clusive franchise whenever he should find a thing which is im- 
possible to define, and which he could not recognize if presented 
to him. It charges him with the duty of investigating questions 


of novdty and utility^ chiefly the former, and gives him the 
means whereby he can discharge that duty efifectively, and to the 
public benefit. But what is " invention ? " Who has ever seen 
** inventive faculty " at work, and by what signs can we distin- 
guish its product from that of "ordinary mechanical skill?" 
There are no answers to these questions. There is no diflference 
in kind between the one class of results and the other, and the 
dividing line will never be drawn. The Supreme Court has ex- 
pressly and repeatedly declared that — "The patent ih prima 
facie evidence both of no'Velty and utility. ^^ (Lehnbenter v. 
Holthaus, 106, U. S.) Gandy v. Main Belting Co., 143, U. S. 
Western Electric Co. v. La Eue, 139, U. S. These are some of 
the most recent decisions of that court, and as the proposition is 
purely one of law, it applies equally to all cases. We find here 
a recognition of the duty of the Commissioner under the law, 
to investigate and decide the novelty and utility of the improve- 
ments in arts, machines, manufactures and compositions of mat- 
ter, for which patents may be sought ; but I am not aware of any 
decision declaring or implying that the Commissioner is called 
upon to decide in any case whether " the inventive faculty " has 
been exercised or not, and it is impossible to suggest any reason 
why the Patent Office should assume so onerous a duty. 

In making investigations and advising applicants of the results 
of such investigations, to the end that they may not through 
ignorance claim things that are really old, or already patented to 
others, and for want of such information be led to difficulties and 
loss, the Patent Office is performing a magnificent service to the 
country. For that service it is equipped with facilities and with 
a trained corps of experts, the like of which exists nowhere else 
in the world. It is in this respect that our patent system is in- 
comparably superior to any other. To what end are these 
elaborate investigations made, and for what reason are they 
beneficial to the public ? He who supposes that the main object and 
beneficial result is to suppress in defence of public interests the 
issue of patents that could not be sustained, is surely in grievous 
error. That sach is not the case is proved by the workings of the 
English patent system for over a hundred years, and by the 
practice of every country of Europe where, with the exception 
fo Geraiany, patents are granted without any investigation what- 
ever. Nothing but actual or wilful blindness can prevent 
recognition of the fact that, to arrest the grant of a doubtful 
claim, for fear the patentee might in some way use it unjustly or 


mischievously, is the least of all the purposes which the Patent 
Office is expected to fulfil. No, the object and the merit of the 
examining system is, that it advises inventors of the state of the 
art^ and thus prevents them, not from imposing upon the public, 
but from deluding and injuring themsel/oes. If, with the results 
of the examiner^s researches before him, and with but a slender 
margin of novelty remaining, the applicant assumes the risk of 
a favorable judgment by the courts, and is willing to pay the 
required fee for a patent of doubtful value, I can conceive of no 
possible reason why the Commissioner of Patents should interpose 
objection. So far as I can see, after the best consideration I am 
able to give to the matter, the only question involved is a fiscal 
one ; and while it would often, in such a case, be a friendly act 
to the inventor to prevent his paying twenty dollars into the 
treasury of the United States, that is surely his affair. 

If then, there ought to be a general rule in such cases, as I 
think is manifest, why would not the best rule be, to give the in- 
ventor in every case where he is willing to pay for it, a patent to 
the extent of the novelty of this improvement ? This is an im- 
portant question, and if there be any reasons why such a rule as 
this should not be established, I should be glad to hear and 
consider them. Of all that could be urged in favor of it, I will 
here suggest but one thing more; namely, the intelligibility and ease 
of application of the rule. Of late years the efficiency of our 
Patent Office has been at a minimum, because of the enormous 
accumulations of work, and the unreasonable time that must elapse 
between the application and the grant of the patent. Ko 
one, who has ever had business before that office, need be told of 
the prodigious waste of time consumed between examiners and 
solicitors in the hopeless and unprofitable discussion of what is, 
or what is not an "inventive act." The disputants in such cases 
must be aware that they do not know, and never can know the 
truth of the matter ; and surely it would seem that the time con- 
sumed in searching for and citing inappropriate decisions, which 
serve only to cloud a subject already hopelessly obscure, conld 
more profitably be employed in those searches for novelty for 
which the office was created, and for which, out of the pockets of 
inventors the Commissioner and examiners are paid. 

Finally, not only are examiners (being but human) incapable 
of deciding whether a departure involves "invention" in the 
metaphysical sense, but manifestly it is particularly unfair to re- 
ject on this ground an application for a novel improvement, how- 


ever seemingly trivial ; because to decide that question at the 
stage of development which an invention has reached while yet 
under examination in the Patent Office involves prejudgment. 
When the court decides this question, it looks and gives heed to 
the results that have followed from the alleged invention and 
patent. This is but the application of the maxim of divine 
wisdom that a tree shall be known by its fruits. But to pass 
upon this question in the Patent Office, requires the examiner to 
judge by the fruits before the tree has sprouted, and to do that 
he must have, in addition to the gift of second-sight, that of 
prophecy. No one, I think, will dispute that this is too much to 
ask of a body of hard working and faithful public servants, 
particularly at the rate of compensation now fixed by law. 

I submit then to my associates in this Institute, whose mem- 
bers are working in a field where, of all others, it is most difficult 
to predict the results of trifling departures from established 
practice, and to whom, therefore, the questions that I have so 
inadequately discussed are of the deepest interest, that the 
Patent Office can best justify the wisdom of its founders, and 
best promote the welfare of the whole people, by adhering to 
the rule of granting to every applicant a patent for all that is, 
or appears to be, novel in his particular improvement. If my 
conclusions be sound, and my reasons have anything like the 
force that I suppose, there is clearly room for a beneficial change 
in the policy of the Patent Office, but it does not lie in the 
direction which at this time it appears to be taking. 


The Secretary read the following communications from Messrs. 
Vansize and Thompson : 

Mr. W. B. Vansjze : — The matter called to our attention by 
Mr. Mauro is of great importance. I understand that the pres- 
ent administration of the Patent Office is enforcing a policy 
which is undoubtedly novel. Our patent laws and the practice 
of the Patent Office have heretofore been regarded as liberal, just, 
generally satisfactory, and fully within the scope and spirit of 
constitutional authority. It seems that the novel policv recently 
inaugurated embodies a general rule of action to be followed by 
the various departments of the Patent Office, according to whicn 
an invention or improvement fully described and properly 
claimed, shall be rejected and a patent refused whenever the 
means sought to be patented is deemed to have been attained 
without the exercise of the inventive faculty, or when by com- 
parison with the state of the particular art the examiner is of 

1894.] DISCUSSION. 69 

the opinion that no " invention" was involved in its production. 
This is equivalent to determining that if the particular examiner 
or department in question were called upon to supply a certain 
means to attain a certain end he would immediately, upon read- 
ing the prior patents or publications, supply the demand with the 
arrangement of apparatus described and claimed by the appli- 
cant for a patent. Of course this conclusion would differ with 
the different examiners. We cannot reasonably accuse each and 
every one of the thirty-six examiners of having this high de- 
gree of intelligence and technical skill. It would seem very 
natural and very equitable that in case of doubt in the mind of 
the examiner, such doubt would be resolved in favor of the ap- 
plicant, and that the application would be allowed, but I under- 
stand from Mr. Mauro, and it is my observation from my own 
recent practice, that the reverse is the case. 

It it very difficult for me to see why this should be so ; it cer- 
tainly is not in harmony with the practice of courts of equity 
when called upon to pass upon the validity of a patent in dis- 
pute. The courts are, and always have been, controlled by the 
doctrine that " A patent should be construed in a liberal spirit 

" to sustain the just claims of the inventor Liberality, 

*' rather than strictness, should prevail where the fate of tne 
" patent is involved, and the question to be decided is whether 
*' the inventor shall hold or lose the fruits of his genius and his 
*' labors." (Kubber Company vs. Goodyear, 9 'Wallace, 788 ) 
" Patents for inventions are to receive a liberal construction, 
** and under the fair application of the rule, ut res magis val'eat 
^' qucmi pereaiy are, if practicable, to be so interpreted as to up- 
" nold, and not to destroy the right of the inventor." (Turrill vs, 
*' Railway Co., 1 Wallace, 491.) 

Those are the declarations of the Supreme Court of the 
United States relative to the construction of patents. Keasoning 
upon that doctrine controlling the treatment of patents, it would 
seem that the same doctrine snould control the Patent Office in 
dealing with an invention upon which a patent is asked to be 
issued. The Patent Office is bound and controlled by the de- 
cisions of the courts upon any contested question. Why is it not 
bound and controlled in cases where the practice is so clearly 
parallel and coincident \ 

The novel policy of the Patent Office will often operate to 
" destrov the right of the inventor," and cuts off all chance for 
the application of any such liberal rule unless you choose to in- 
cur the expense of going to the court to secure the grant of your 
patent. This puts the Patent Office in the position of obstruct- 
ing rather than encouraging advancement in the useful arts. I 
gather from Mr. Mauro's remarks that the Patent Office has been 
moved to initiate its novel policy by reason of the fact that 
several patents have recently been found by the courts to be void 
for want of invention. This causes us, naturally, to inquire: 


Would it not be better policy and better practice for the Patent 
Office to follow the very liberal doctrine declared by the Supreme 
Court in pursuance of which an inventor might secure his patent 
rights, and this, even in cases where there existed reasonable 
doubt on the so-called question of "invention"? In this case 
the possible error of the Patent Office could be rectified in the 
courts. If you deny a patent, yon cut off all chance which the 
inventor might have of securing suitable protection and remune- 
ration for his possibly meritorious invention. You condemn his 
invention and you deny that you may in error. Our papal friend 
in Rome cannot exceea that doctrine. In my humble opinion, 
if change is desirable, it would be far better to abolish all exami- 
nation as to merits, and grant a patent to any applicant upon 
payment of the proper fees. That is the English custom, and it 
certainly avoids the rank injustice into which this novel policy is 
forcing us. 

Of course, I am cognizant of the fact that you can appeal 
from the primary examiner to the Board of Examiners, and fail- 
ing in the Patent Office apply to the court. This is very expen- 
sive in time and money. Why not grant a patent in the first 
instance and then go to the court and test any doubtful ques- 
tions^ It is certaiiily more satisfactory and less liable to result 
in that loss and injustice likely to occur in many cases fn»m the 
denial of adequate protection to meritorious inventions should 
the novel policy be insisted upon. 

Mr. Edward P. Thompson : — What the author terms a rumor 
as to rejection of applications for want of exercise of the inven- 
tive faculty and for giving the doubt of patentability to the 
t)ublic, is more than a rumor, as I can testify that comparatively 
ately I have had more applications rejected for alleged want of 
invention than formerly. The examiners do not deny novelty 
but declare lack of invention, in more cases than formerly. This 
is my experience. I agree with Mr. Mauro that this policy is not 
for the public benefit. 

While I have had applications freely rejected upon the ground 
of want of exercise oi inventive faculty, I can compliment the 
examiners upon their fairness in reversing their decision upon a 
proper showing and argument. In general, I argue that, inde- 
pendently of the decisions of the courts, independently of the 
commissioners' decisions and many other authorities and cases, 
the United States patent statute 4,886, shows very clearly what 
the examiner's duty is. Let us learn the exact wording. It 
states that : *^ Any person who has invented or discovered any 
" new and useful art, machine, manufacture or composition of 
" matter, or any new and useful improvement thereof may ob- 
" tain a patent therefor." The statute states other matters as 
to foreign patents, public use, etc., which have no relevancy here. 

That which is new and useful is an invention. As soon as the 
Patent Office, United States courts, and other authorities will 

1894.] PISCUSSION. 7^ 

take this statute as their guide, they will find nothing whatever 
as to exercise of inventive faculty. 

In no other department of law would the merits of a case be 
decided except upon facts, especially when facts exist. The two 
facts to be set forth are novelty and utility, which if existing 
prove invention. The degree of novelty can be determined and 
admitted by the examiner. The degree of utility can be known 
by affidavits and more accurately only after the invention has 
been used by the public. Let novelty and utility determine pat- 

Mk. Theodor J. W. Olan : — I have lately had some experi- 
ence >vith reference to the Patent Office, and the practice of di- 
viding up patents, in the way examiners have tried to do it, has 
been especially pressed upon my attention. I lately had an ap- 
pUcation in for one patent — I snpposed it was one — but the first 
commnnication I had from the examiner informed me that I had 
twelve inventions there instead of one, and he wanted me to di- 
vide it up into twelve applications. He said that the different 
parts of this invention had alreadj' entered into the art as sub- 
jects for different inventions, and it was unreasonable to expect 
that the Patent Office would grant a single patent on so many in- 
ventions. I could not find that tliis examiner's view was sustained 
by the law, so I wrote a letter in which I told him that I failed 
to find any section of the patent law, or any section of the rules of 
practice of the Patent Office, which would allow him to take such a 
view of the matter. I asked him : " What could not be said to have 
entered into the arts as subjects for different inventions.". " If," 
said I, "one inventor whose inventive capacity should turn 
'* around a head of a pin, should ask that a patent be granted to him 
" for a certain form thereof which he thought useful for one 
" purpose or another, should now another inventor, therefore, be 
" obliged to file his application for another patent relating to a 
"complete pin in two different applications r' I said that I 
thought there was no other way than this to find out which was 
an independent part in a patent case : namely to see if for any 
special part of an invention a special and independent patent 
could be granted without injury to the entire invention. That 
is to say, that the different patents which might have been issued 
for different parts, could, without injury to any of those parts or 
without injury to the whole invention, come into the hands 
of different contesting owners. I said that if they could not 
do that, then that was a proof that the paints in question were not 
separate inventions and that the inventor could not be called 
upon to file so many applications for what he thought was one 
single thing. I then received an answer from the examiner. 
He said that he maintained his views, but that he made it three 
instead of twelve. I said again that in order to remove this ob- 
struction, I will cut away the claims he had asked for under pro- 
test. I had also said, in my previous letter, that 1 hoped in my 
own interest, and in the interest of other inventors, that should 


tlie examiner not approve my views there expressed, Congress 
might do it before long. Then shortly after, 1 saw in a Wash- 
ington paper that the Commissioner had just tliought of altering 
the practice, and I wondered if that did not have something to 
do with this practice of the examiners of cutting up and dissect- 
ing the inventions so much. It might not be so much their wish 
to refuse small patents as their desire to get as many fees from 
the inventor as possible for one single thing by dividing it up. 

The President : — I see Mr. Forney, the editor of the Amer- 
ican Engineer, here. I know tlie Institute would be glad to hear 
him on this subject on which he is abundantly capable of speak- 

Mr. M. N. Forney : — I do not know that I have anything that 
I could add to this discussion which would be of interest to the 
gentlemen here. I have gone through some of the tribulations 
which most inventors go through at the Patent Office. I liave 
suflEered from the division and sub-division of my patents, and I 
have also suffered, as others hnve who are in the habit of going 
to Washington for patents, in sometimes having my applications 
rejected. The fact of there being a new rule adopted in the 
Patent Office is, however, new to me. I was not aware that any 
new system had been introduced there, and it probably accounts 
for some things that I could not account for in my own experience 
recently. Anything, 1 think, which would take away from the 
liberality of our patent laws ought to be very much regretted, 
for the sake of the general advancement of the arts and sciences. 
Few of us realize, perhaps, how much this country owes to the 
patent system whicli was inaugurated by those wise old fellows 
who founded our government a great many years ago. The 
question has very often come up as to what the result would 
be in case the patent laws were abolished. I think some of us, 
perhaps, by citing our own experience can give an indication of 
about what would happen. I Icnow in several instancies in which 
I have had inventions, of probably very little merit, but at any 
rate, I made application for patents for tliera in the Patent Office, 
and it has happened, in a number <>f instances, that I have dis- 
covered that someone else had anticipated my inventions. The 
result of it was, I simply dropped the whole scheme, paid no more 
attention to it, and did nothing to develop it, altliough at the 
time I had the impression that the inventions were of value. Now, 
if that same principle is applied all over the country, to all in- 
ventors and to all inventions, the obvious result would be that 
invention would stop, and then instead of inventors devoting 
their time and thought and energy to the subject, they would 
simply devote their time and energy to some other purpose. 
They would go into trading or into speculating or something sim- 
ilar. The object of inventing to most of us is not entirely the 
love of invention, but because we hope to realize some profit 
froin it. Therefore, it seems to me that any policy of the Patent 

1894.1 DISCUSSION. 78 

Office which looks to a less liberal construction of tlie patent 
laws or the practice would be very disastrous not only to inven- 
tion generally, but it would be a step backward in the prosperity 
of the country. 

Mr. Joseph Sa^chs:— The rejection of an invention for want 
of patentability I really do not consider so very undesirable a 
feature of Patent Office practice. To my mind the examiner 
has in view, in doing this, to discover whether the inventor him- 
self really believes that he has discovered any new process or 
machine By showing the inventor, or trying to show the in- 
ventor, that he has not, and citing certain instances where similar 
devices have been used in similar ways before, he brings forth 
from the inventor a series of ideas by which the inventor tries 
to show that he has invented something, and if those ideas which 
the inventor puts forth go to show that the invention is actually 
a valid one, tiien in most cases the examiner will take back his 
former decision and grant a patent for the invention. 

I have found withm the last two or three years that of very 
nearly fifteen applications that I have made, the greater part of 
them have been rejected for the want of patentability, the want 
of invention. I have never been quite as lucky as one of my 
predecessors in having found that there were twelve inventions 
in what I thought was one ; but I frequently found that the ex- 
aminer thought there was no invention at all. That in view of 
patent number so and so in combination with patent number 
something else, the mere addition of a screw or spring or some- 
thing else did not constitute invention. But upon my showing 
that this spring or screw or something else was absolutely neces- 
sary to gain this new effect, the patent was generally allowed. I 
really tfiink that the mere citing of instances to bring forth ideas 
from the inventor, showing that his idea is a new and valid one, 
is not detrimental at all to our inventive advancement. I think it 
gives the inventor strength and gives him opportunity to show 
up the points of advantage in his invention, and if his invention 
has no points of real advantage he should not be granted a patent 

The President : — The Chair may perhaps be pardoned if he 
adds his little to the history of the annoying experience in the 
Patent OflBce that may be summed up under that very disagreeable 
phrase, "lack of invention." Very early in the history of the 
art he attempted, in connection with Elihu Thomson, to take out 
a patent for what was practically the first transformer ever ap- 
plied for in this country. We showed an induction coil with a 
long thin primary and a short thick secondary, and the erudite 
examiner rejected the application on the statement that it con- 
tained or snowed no invention. I remember the phraseology 
fairly well, as it made quite an impression on me at the time, be- 
cause I knew that we had a valuable new idea. The examiner 
informed us that it did not constitute an act of invention merelv 


to eliange the relative proportions of the resistance in the primary 
and secondary wires. We know that it was, so to speak, a great 
invention as it gave to the world the transformer in place of the 
ordinary Ruhmkorff coil. The great trouble in this reepect in 
the Parent Office comes from the fact that the examiners are in- 
adequately compensated for their services. We should pay suf- 
ficiently high salaries to get unquestionably first class men. A 
broad-minded man that knew anything of the art never could 
have made a mistake like the one I have mentioned. I do not at 
all wish to be considered as sitting in judgment on the examiners 
in the Patent Office, especially in the very difficult department 
of electricity. They are excellent men. But I do think that a 
great improvement would come in urging the government to set 
aside a fair proportion of the profits of the office and apportion 
them more among the examiners in the way of increased salaries. 
I think a real reform could be worked in that direction. 

[Communicated aftkr Adjournment by Mr. Almon Robinson.] 

Those of us whose specialty is the making of small inventions 
owe the author a considerable debt for setting forth so clearly 
and forcibly our claims to recognition. 

It is generally admitted that inventors of the other sort, who 
patent their untried dreams and get broad claims on them, de- 
serve encouraojement ; hut it is thought that the more carefully 
considered things, which show fewer unheard of features, will 
come along by themselves. Anyone who has had occasion to 
closely watch the way in which new devices and methods come 
into use knows that this is a mistaken view. 

I call to mind a case in which a manufacturing firm made a 
long and persistent effort to obtain a patent on a well tested im- 
provement in their owfi line of work. Failing on account of 
alleged lack of invention, they decided to drop the thing entirely, 
not caring to fit up for making it without the protection of a 

Another case can probably be paralleled from the experience 
of many members of the Institute. A crude electrical ideawaa 
carefully spread out by a skilful patent lawyer. An independent 
inventor offering the same idea worked into practical shape, waa 
told that there was no patentable difference. Neither of the de- 
vices are in use. 

The necessary result of the threatened restriction would be ta 
take away all inducement for trying to make something useful 
out of the impractical anticipation which is always standing in 
every one's way. 

The real trouble, however, with the supposed plan of the Com- 
missioner, is not that he is fighting an imaginary evil, but that 
the office will unavoidably work injustice in carrying out hia 
ideas, and this will come from something that lies deeper than 
any personal shortcomings of the examiners ; from the fact that 

1894.] DISCUSSION. 75 

an examiner has loaded upon him the distinct and incompatible 
dnties of state's attorney and judge. He is first called upon to 
hunt up every possible objection to the granting of the patent, 
and must then sit in judgment upon his own work. It is not in 
human nature for him to judge fairly. 

It is easier to point ont the diflSculty than the remedy, but I 
venture to suggest a modification of a plan that has been before 
brought forward. Let the examiner do his worst and set forth 
all the objections known to him, and give the applicant the privi- 
lege of taking out a conditional patent, on which all the exam- 
iner's references and objections are endorsed, and print these 
with the claims in the Gazette. 

Endorse on the printed copies and publish in the Gazette any- 
thing fnrther which comes to the knowledge of the examiner so 
that the full state of the art as he understands it shall be at all 
times accessible to the public. Then provide in the Patent Office 
a board of appeal before which the patentee must take all 
matters in dispute before attempting to collect damages of in- 

I ask attention to one feature of this plan. It leaves the state 
of the art in full public view. Most workers in the electrical 
field can appreciate the advantages of this. 

Lewiston. Me., February 27, 1894. 

The President: — Are there any further remarks on this 
paper ? Shall we proceed to the next paper, or shall we now 
consider the election rules ? 

Nothing being said, I shall consider that it is the desire of the 
meeting to hear Mr. Leonard's paper. 

Mr, H. Ward Leonard then read the following paper entitled 
" How Shall we Operate an Electric Railway 100 Miles from the 
Power Station." 

A pa/tr pretemttd at the S4tk Meeting of the 
American Institute of Electrical Engineers^ 
New Vork^ February 2ist^ 1S94. President 
Houston in the Chair. 



Let U8 suppose that we are called upon to act as engineei's for 
a steam railway desiring to operate its line by electric locomo- 
tives. There exists a very economical source of power, possibly 
a water power, so situated that the length of railway to be 
operated in either direction is 100 miles. 

Let us determine the leading points of the specification for 
such a road, based upon our experience to this date, and after 
making the specification, let us see whether we are to-day able to 
comply with the specification, and if not, what must be done 
before we can comply with it. 

The following features seem desirable, if not essential, in such 
a railway : 

1st. A single trolley contact shall be used for supplying 
current to the locomotive. 

2nd. The e. m. f. upon the trolley shall not exceed 500 volts. 

3rd. There shall be no apparatus in motion and requiring 
attention, between the power station and the locomotive. 

4th. No commutator, rheostat or controlling device on the 
locomotive shall be subjected to a higher e. m. f. than 250 volts, 
and there shall be no sparking on any of the apparatus under 
any normal conditions. 

5th, The entire control of the locomotive in either direction 
shall be effected by the movement of one lever. 

6th. The load shall be started from dead rest by an amount 
of energy taken from the source of supply, which shall not ex- 




ceed one quarter of the energy required to operate at full speed 
on the level. 

7th. The retardation of the load in coming down grades, and 
in stopping, shall be effected by converting the motors into 
generators, which shall feed back current to the line, and thereby 
assist the power station in operating other locomotives. 

8th. The motors must be reversible when operating at full 
speed, without damage to the motors or other apparatus. 

Fio. 1. 

Am Si^le phnsc *Uertiat>n« cUTTtrvl generator of i.doc voJu. 

^1 StBf^itp trRfiafonncT' frtini t^ooq to arj,op^ volts k 

C. TFiUJimliakin circuit ai lio^coo volt*. 

T^, Sip?>-Jown irflnafoTmcr, ^o^ooo m joa vo)t*. 

E. Tfolley. 

F, Trolley wire, joo volts. 
G» Ofoutid, 

H. Synchfunouft flinKle pbtme trkitor* 

I. Contifiuou* cturmi cvrntmiiiaior of 250 vuli* snpuMnB 

fields of H. Kaitd L. 
K. Cif»«tiOiJoys riirftrnt ij^neisnur^ 3«io vck*. 
h. Con ti nuptis currsTTi ■ n^. -r ■ ■ - . / n o vol ts 
M. Reversing rheostat m separately excited field of K. 
N. Driving wheel of locomotive. 

9th. The efficiency of the system from power on the genera- 
tor shaft to the draw bar pull of the locomotive, shall be at least 
50 per cent. 

10th. The locomotive shall produce at least 500 h. p., when 
operating at a speed of 80 miles per hour. 

It will be evident that we must use a high e. m. f. for operating 
over such great distances. The average distance over which the 


power is to be transmitted is 50 miles, and we find that in order 
to operate with a loss in conductors of 20 per cent., we must have 
an initial e. m. f. of 20,000 volt8,,in order to make the cost of 
copper about $20 per k. w. which is about the best figure for cost 
of copper under the conditions. 

The alternating current must evidently be used for such an e. 
M. F. as this, and the single phase alternating, since we have but 
one trolley contact. 

Let us start (see Fig. 1) with the standard 1,000-volt single 
phase alternators in our power station, and convert by step-up 
transformers from 1,000 to 20,000 volts required for the trans- 
mission circuit. Since we are limited to 500 volts upon the trol- 
ley, we must insert at suitable points, say every two miles, a 
converter, which will transform the energy at 20,000 volts in the 
transmission circuit, to energy at 500 volts in the trolley circuit, 
one pole of which latter circuit will be the rails. 

We have our energy delivered at our point of use with reason- 
able cost and efficiency and by simple and well tried apparatus. 
But the energy is in the form of a single phase alternating cur- 
rent which is not very flexible. 

We can operate a synchronous alternating current motor by 
this current, but it cannot be regulated in speed or reversed in 
direction, and cannot be started under load, and will be thrown 
out of step if a large load be suddenly applied. As all of these 
conditions are required of the locomotives, a motor operating by 
the alternating current evidently cannot be used directly. 

But it is a simple matter to start the synchronous motor with- 
out load and when it reaches its synchronous speed it will perform 
work eflSciently and satisfactorily, provided it be not subjected 
to violent fluctuations in the load applied to it. 

Evidently, then, what we need is some form of gearing between 
the synchronous motor and the axle, which will give us the de- 
sired control and enable us to operate at any speed and in either 

It is quite possible that this can be accomplished mechanically, 
and many ingenious devices for this purpose have been invented, 
but none seem to be suflGiciently simple, reliable and lasting 
for use on such a large scale. 

The equivalent of such a mechanical gear can, however, be 
secured if we will make use of the synchronous motor merely to 
drive a continuous current generator on the same shaft at a con- 


stant speed, and use the continuous current so generated to 
«upply the propelling motors connected with the axles of the 

Since the generator is used for the motors on one particular 
locomotive only, we can vary its e. m. f. at pleasure, and 
hence can produce a low s. m. f. for low speeds, and inqrease the 
E. M. F. to increase the speed and by this means avoid the loss of 
energy which is wasted in rheostats when motors are started 
under load, and when connected as usual upon a source of 
constant e. m. f. 

In order to secure rapid changes in the e. m. f. of this continu- 
ous current generator at will, it will be best to have its field 
separately excited which will also enable us to reverse its field at 
pleasure. The propelling motors can be series, shunt, or sepa- 
rately excited. The best results will be obtained by separately 
exciting the field, and keeping it fully and constantly excited and 
reversing the motors by reversing the field of the generator which 
of course will reverse the current in the armature alone of the 

To secure this exciting current for the synchronous alternating 
motor, and also for the fields of the continuous current genera- 
tor and motor, it will be best to drive by means of the alternating 
motor armature, and if desired in the same field, a continuous 
current winding connected to a commutator, from which will be 
led the current for exciting the fields of all three machines. 

Let us wind the fields for 250 volts, and also use this voltage 
for the continuous current armatures. This pressure is perfectly 
safe and can be handled with impunity. 

Suppose now the locomotive to be at rest. The synchronous 
motor is running and driving the generator armature at full speed 
in a field of no intensity, hence the propelling motors receive no 
current. We now make the first contact upon the rheostat in 
the generator field circuit and let the resistance in the rheostat be 
such as to produce say 25 volts at the genemtor brushes. 

This 25 volts will supply a very large current to the motor 
armature at rest in its saturated field, and consequently will pro- 
duce a sufiicient torque to start the entire load and continue to 
move it at a slow speed. 

We are using 25 volts and let us say 2,500 amperes in this cir- 
cuit ; this means 62,500 watts and disregarding transformation 
losses for simplicity, this means a current of 125 amperes from 


the trolley. When operating at the rate of 500 h. p. at full speed 
we shall need say 1,800 amperes and 250 volts in our propelling- 
circuit, which is 450 k. w. and means roughly 900 amperes from 
the trolley. It is evident therefore, that we can start the load 
with but a small fraction of the energy required for operation at 
full speed, and that there will be no danger of throwing the al- 
ternator out of step by applying but about one sixth of its full 
load and applying that gradually as will be the case, as the load 
will follow the increase of the generator field strength, which 
although rapid, is gradual and not instantaneous. 

If we are operating at full speed, and desire to bring the loco- 
motive to rest, we gradually but rapidly reduce the strength of 
the generator field by manipulating the rheostat in its field cir- 
cuit so as to reduce to zero the current exciting this field ; the 
E, M. F. produced by the generator then rapidly falls below the 
counter e. m. f. of the motors, which are being driven in a con- 
stant field by the momentum of the moving load, and the motors 
consequently become generators, and supply current to the 
former generator which now becomes a motor, and driving the 
alternator, feeds current back through the trolley, thereby not 
only bringing the locomotive smoothly and rapidly to rest, but 
saving the energy usually wasted upon the brake shoes. 

Under this arrangement, if we are using steam engines as the 
source of power, we never subject the engines to the violent 
fluctuations ordinarily met with in electric railways, and by 
reason of having a comparatively steady load, can secure very 
high economy in the consumption of steam, and since we have 
eliminated the excessive load in starting, we can very much re- 
duce the capacity of the engines, generators and conductors over 
usual requirements. 

The reversal of the motors is very simple and smooth by this 
method. The lever of the rheostat in the generator field circuit 
is moved, so as first to reduce the current to zero, and then in- 
crease it again to its maximum but in the opposite direction 
around the field. Tlie reversal of the motor armature, follow- 
ing the gradual change in the strength of the generator field, is 
extremely smooth, and the armature is not subjected to any sud- 
den strain. No sparking will be met with under any condition, 
upon either the generator or motor commutators, or upon the 
field rheostat. 

The combination of apparatus, and method of use I have de- 


flcribed, enable us to conform fully with the specification given 
above, and while it is possible that the future may make this 
arrangement appear clumsy and crude, it has the present advan- 
tage of making use of apparatus we are all familiar with, and 
manufactured by a score of different concerns, and such an ar- 
rangement as 1 have described will serve a useful purpose until 
we can get the perfect single phase alternating motor, or the 
motionless transformer for continuous currents, which we have 
needed and waited for so long, and which many people even yet 
expect will eventually be realized. 

Personally, I have for some years believed firmly that the 
transmission of large amounts of energy over long distances 
must be done by the alternating current, and that the continuous 
current is the only suitable one for the eiBcient operation of 
motors which must be varied in speed, torque and direction. 

Hence, I believe that the lines I have described above will be 
the lines of future practice ; namely, the use initially of an alter- 
nating current which will be converted upon the locomotive to a 
continuous current, and used in this form in the propelling motors. 

After reading the paper, the author described his apparatus, 
which was in operation upon the platform, as follows : 

The two bnishes on the armature of this motor are connected 
directly to the two brushes on the generator, there being nothing 
in the circuit of the armatures, and the field of the final motor 
being directly across the line, and consequently being continu- 
ously and fully excited in one direction only. Of these instru- 
ments — ^in order to give you an intelligent idea of what we have 
here, this is merely a starting rheostat for starting the motor gen- 
erator under friction load. These two instruments read the vol- 
tage and current of the supply circuit, and I have selected an 
instrument for reading the current for supplying the whole 
system, with a rather large index, so as to clearly show the small 
current required to start the load. These other two instruments 
are connected with the armature circuit, the voltmeter and the 
ammeter. Both of them have their zero at the center and will 
read in either direction. As the current in this armature circuit 
is reversed, you can read the volts and amperes in both direc- 
tions ; the only instrument probably that you could observe the 
readings of, except perhaps later by closer examination, is the ii - 


etrament reading amperes from the supply line at a constant po- 
tential of 110 volts. Now we have the motor generator in 
operation with its friction load, with its field excited, and with 
the field of the final motor fully excited also, but witli no current 
around the field of the generator — the intermediate machine. I 
have here a brake which will enable us to give the final motor its 
full torque. But I will first remove the brake to show the per- 
formance of the armature under conditions of no load whatever. 
I have placed a chalk mark on the inside of this pulley, with the 
idea of having you see that the armature is in rotation. I have 
also made a chalk mark on the head of the armature at this end. 
It is now turning at perhaps one turn in four or five seconds, 
xmder merely friction load due to the residual magnetism of the 
iield of the generator. There is no current in the field of the 
generator, but there is a little residual magnetism. I find from 
reading the instrument that the voltage is now about two volts, 
and the amperes something like half an ampere, and there is, of 
course, no work of any kind being done, but the very slow rota- 
tion of the motor armature in its bearings. Now under the con- 
ditions that we have in this final motor, it having a constant 
field, the torque will be proportional to the current, and as we 
are in a position where we can vary the voltage supplied from 
the generator, the speed will be proportioned altogether to the 
electromotive force supplied, and since the 'product of the volts 
and the amperes represents the electric energy that we are using 
in that circuit, and since the speed times the pull in pounds, rep- 
resents the work which is being performed by the motor, the 
conditions that we have here are such that, disregarding the exci- 
tation currents, we have a perfect eflBciency imder any conditions 
of speed or torque in either direction. There is no waste of 
energy in rheostats, as is usual, and the very strong field of the 
motor fixes the lines of force so that there will be no sparking 
upon the motor commutator, and although a great many have 
anticipated that there should be sparking upon the generator 
commutator, there is no sparking upon that wnatever, and I will 
briefly state what appears to me to be tlie reason for this. In the 
case of a motor of constant potential, we know that if we weaken 
the field with a large armature current it will spark very badly, 
and it is probably from this knowledge that it was anticipated 
that the generator under similar conditions would also spark. 
But the conditions are diflFerent in this respect. In the ease of a 
motor we have the full electromotive force upon the commutator 
and therefore practically a constant "volts per bar" and then 
weaken the field under these conditions. In the case of the gen- 
aerator the volts are a function of the field, and as we weaken the 
field of the generator, the volts per bar are reduced simulta- 


neously and proportionately, although there is a very marked dis- 
tortion of the field generator, and a very strong lead of the neu- 
tral point under the conditions of a weak field and a very strong 
armature current, the neutral point bein^ perhaps distorted thirty 
or thirty-five degrees from the line on wnich the brushes rest, the 
volts being brolcen by the brush are so slight on account of the 
low total £. M. F. being produced that no sparking is met with. 
Now as we cut out the resistance in the generator field circuit 
step by step, the amperes required by the motor will be practi- 
cally constant as the torque is practically constant, but the volts 
on the armature circuit as we cut out the resistance will gradually 
rise, and the speed proportionately. Now the machine is running 
at full speed in one direction, and now we quickly reverse it to 
full speed in the other direction under full load, and as will be 
noticed without any sparking. 

One point that is spoken of in the paper is the restoration of 
energy to the line of retardation of the moving load. I will now 
lift the brushes of the motor while it is running at full speed 
without load. The motor continues to run for a very long time, 
as the friction of its bearings is the only thing that is tending to 
stop it, and it is moving at a very high rate ot speed, something 
like 1,800 revolutions per minute. Sut under the conditions of 
practice, hj moving the generator field rheostat to the center, that 
18, weakenmg the field of the generator, the motor being driven 
by its momentum, produces an electromotive force which soon 
becomes higher than that of the generator, which is rapidly fall- 
ing, and it therefore feeds current back. Consequently you will 
see that the motor comes to rest very quickly, and in so doing its 
entire effort is in the production of energy to drive the interme- 
diate dynamo as a motor. While it is running at full speed in 
that direction, we can instantly reverse it to full speed in the other, 
as you see. 

Now, the full brake load of the machine, that is, the full 
torque, is given it by this weight applied to this point. You will 
notice the index of the ampere meter here, and everything be- 
ing at dead rest, this small current would represent the amount 
of energy that would be required to excite the field and over- 
come the friction load. Now, making the first contact here, 
we give the generator field a very small current. We are send- 
ing an amount of current through this motor armature which 
tends to make it go. The amount «f current that it is receiving 
is six amperes, aod it is not a sufiicient torque to start under the 
brake losud. The next contact gives us a little more than eight. 
It now starts and is turning very slowly, with an amount of cur- 
rent which is a little more than this motor is designed for. It 
has the full load and it can be made to move at a speed which is 
very slow, about 15 revolutions per minute, and, as you have no- 
tic^, the ampere meter here in the supply line has moved almost 
nothing, less than one ampere, from the position in which it was 


originally. As we now increase the field strength of the gene- 
rator, we gradually get an increa^e of electromotive force from 
the generator and the energy from the line goes up just a^ we 
increase the load. Now we are running at full speed and doing 
fnll work. While running at full speed we now instantly reverse 
the field and go nt full speed in the other direction. 

Now, under condition of the ordinary rheostat control of ap- 
paratus, this full working current would be required for accele- 
rating the motor under full load. Here I am recording in the 
armature circuit an amonnt of current which is something like 
12 amperes, which is about 60 per cent, more than its full brake 
load, but the b. m. f. is only 20 volts. That same amount of cur- 
rent would be required to ^ive the same torque if it were used 
in the rheostat method, and tliis ampere meter from the supply 
line in starting from dead rest under fnll load would read about 
60 per cent, more than its full load and full speed reading. In- 
stead of that, starting the load with this system makes only a 
deflection of less than an ampere from the line. Although I get 
in the armature circuit here something over eight amperes — ^by 
the way, in speaking of that I will point out one fact that T 
omitted— that the armature circuits of these machines are 260 
volts here, so that in order to make any comparison of figures 
between the current from line, which is 110 volts, we must give 
due consideration to that. The reversal of the load takes place 
without any sparking whatever and is perfectly smooth. It is a 
feature of this system that the fields of both the getierator and 
the motor have no connection whatever with their armatures — no 
electrical connection of any kind. Consequently in the handling 
of the apparatus there is no tendency to sparking at the brushes 
due to any rapid changes of the field magnetism or any breaking 
of the field magnetism. Another point is that at the time the re- 
versal occurs, the electromotive force produced by the generator 
is zero and there is no tendency to spark. You will notice that 
the current from the supply line goes up perfectly smoothly in 
proportion to the work it is doing. It does not jump beyond 
where it should and then finally come back again. Of course, if 
we were handling anything like a train or any body of large mo- 
mentum the movement would probably be tolerablv slow as com- 
pared with the handling I am giving it now. I do not think of 
any other points that I wish to speak of in connection with the 
apparatus unless some questions are asked in regard to it. 

The Pkesibent: — Mr. Leonard's excellent and instructive pa- 
per is now open for discussion. 


Mr. Charles G. Curtis: — I would like to ask Mr. Leonard 
why it would not be the better plan to place the armature field in 

Mr. Leonard: — Its armature and its field ? 

Mr. Curtis: — Yes. In other words, in starting, a great deal 

1894.] DISCUSSION. 85 

of power is required to overcome the inertia, and the amperes 
required in the armature connected with the wheel would be ex- 
ceedinfcly high. Don't you think so ? 

Mk. Lbonajeu): — Yes. 

Mb. Curtis: — Well, in railway motors ordinarily, it is found 
almost necessary, unless the field is intensely strong, to put the 
field in series with the nrmature, so that the field would have a 
very strong current flowing through it when the armature does. 

Mr. Leonard: — Well, we have a field which is saturated, and 
I do not believe it would be increased materially by any increase 
of current. The field is constantly excited and fully saturated. 
It is directly across the line, and in this case it is the regular 
shunt winding of a shunt motor disconnected from the armature. 
It is connected directly across the line. Of course, if we were to 
Attempt to work with a series wound motor for the last one, the 
reversal of the field of the generator would not enable us to re- 
verse the motor, as it would reverse both the armature and field 

Mr. Curtis :— That could be done by a separate switch. 

Mr. Leonard : — Yes. But I do not see that there is anything 
to be accomplished by that, and you certainly get a variation of 
the field of the motor which is one of the most undesirable 

Mb. Curtis : — ^It seems to me, Mr. Leonard, if you apply a 
very heavy motor to the armature of your generator and weaken 
its field so as to get a very great reduction in the electromotive 
force, as much as 75 per cent, reduction — you would necessarily 
get a distortion of the field. I cannot see any difference between 
the case of a generator and the case of a motor as regards spark- 

Mr. Leonard : — Well, I do not know that I can do anything 
bat try to make it more clear by repetition. In the case of this 
motor here, there are 260 volts across the brushes, and if we 
weaken the field of the motor it would certainly spark very 
badly. But in starting the load there are across the brushes of 
this generator but perhaps twenty volts, and its field is very weak. 
Now with a full current in the armature, that is, the full starting 
-current, there is a very strong distortion of the field, and as I 
said before, it probably amounts to something like 36 degrees. 
We would find that the line of maximum difference of potential 
is some 36 degrees from the line where the brushes are. But at 
the point where the brushes are, the whole electromotive force 
around the commutator being but one-tenth of its full e. m. f., it 
is equivalent to multiplying the commutator bars by ten, at any 
rate, and it really has a much better result than that. There is 
absolutely no sparking from the generator brushes under any 
conditions where I have ever applied it as yet, and I have applied 
it under very severe conditions and in the movement of very 
large loads in electric cranes and elevators. Of course the distor- 


tioD will be first in one direction, and then when the field is re- 
Tersed it will be in the other direction. Therefore your brushes 
should be set for no load whatever. 

Mr. Curtis : — Have you tried it on very large machines — 
large armatures ? 

Mr. Leonard : — Machines of fifty horse-power. 

Mr. Curtis : — How much do you weaken the field when you 
are getting the first part of the starting torque ? 

Mr. Leonard : — There is a resistance in series with the field, 
in a motor of 250 volts and of such a horse power as fifty, of 
perhaps a thousand ohms in scries with the field. 

Mr. Curtis:— How weak will the field be compared with the 
full strength ? 

Mr. Leonard : — About one twentieth. 

Mr. Curtis : — Do you find under those circumstances that it 
won't spark any ? 

Mr. Leonard : — Not a particle. I must smile a little at that, 
because it is the same question that everyone since I first had 
anything to do with the method has raised, and I do not know of 
a single person who has not expected that that generator would 

Mr. Curtis : — I never saw a generator yet where the field is 
weakened that would not spark where you do not shift the 
brushes, and I do not see any difference whether that is feeding 
current to a railway motor or something else. 

Mr. Leonajid : — It is not that. But if you will think a mo- 
ment you will realize that it has been very rarely that a generator 
has been used in the past, where its field would likely be weakened 
to a very great extent, and where its field was separately excited. 
Separate excitation of the field may not be an essential factor 
for non-sparking, but it is infiuential in regard to having the 
armature entirely free from any disturbing field kicks, etc. 

Mr. Cuktis: — Commutator sparking is due to the presence of 
magnetism. In those machines there I should think that in 
all probability the field was so very strong, compared with the 
turns on the armature, that you would not get any field dis- 
tortion unless your field was practically nothing. 

Mr. Leonajid: — It was on these identical machines that I 
spoke of a measurement of 35 degrees distortion. The motor 
armature has a full field, and its lines of forces are necessarily 
kept tolerably straight. But the generator has, at times, no field 
practically, and the lines are distorted tremendously. 

Mr. Cdrtis : — How can you move the coils of the armature 'i 
How can you move it in the presence of lines of force without 
getting sparking ? 

Mr. Leonard : — Well, we are moving it through such a field 
that the lines are so very few that the electromotive force devel- 
oped by the coil which is passing under the brush is so slight 

18W.] DI8OU88I0N, 87 

that the passing of those bars, perhaps, only produces a breaking 
of an electromotive force which is no greater than it would be 
at the neutral point with ten times the total electromotive force 
then in use. 

Me. Cubtis: — Well, 1 cannot agree with yon, Mr. Leonard. 

Mb. Lbonabd : — It may be that I have not the right theory 
about it. 

Mb. Curtis : — It may be immaterial. That is to say, in order 
to make this an efficient mode of operation it would not be neces- 
sary to reduce the electromotive force more than 80 per cent., 
perhaps. Then you would be working with considerable effic- 
iency and the field might stand that very well with 20 per cent, 
of its normal strength. Although I never saw a generator yet 
that had many turns on its armature, with any such capacity as 
that, without burning up the brushes. 

Mb. Leonard : — Well, you can in this case. 1 know that in 
practice this has been used in connection with almost every 
dynamo that is on the market. 

Mb. Cubtis : — What sort of machines have you used it on ? 

Mb. Leonabd : — On the Crocker-Wheeler, the Eddy, the " C. 
& C," the Edison, the Thomson-Houston, the Waddell-Entz, the 
Eickemeyer, the Bilberg, and several others. But in each of 
these it has performed exactly as it has in every other case. 

Mb. Curtis : — Did you ever try those machines as motors and 
see if they spark as motors with weak fields ? 

Mb. Leonabd : — They will unquestionably spark as motors. 

Mb. Curtis: — Did you ever try them? 

Mr. Leonabd : — Yes. I tried these very machines with weak 

Mr. Curtis : — But those machines have an exceedingly power- 
ful field, and weak armature. 

Mb. Leonabd : — They have more turns on the armature than 

Mb. Cubtis: — Compared with turns on the fields? 

Mb. Leonabd : — Turns on the armature. That is, the magne- 
tizing effect of the armature current is rather more in these than 
in many other machines on the market. 

Mb. Curtis : — This is all I wanted to bring out — that when 
you get to machines of any size, I think you will find that the 
magnetizing effects of the armature turns are so much in excess 
of what they are on the smaller machines that you will get 

M. Leonabd: — What size do you mean ? 

Mb. Cubtis: — Take a multipolar machine of fifty, or take a 
railway motor. 

Mb. Leonabd: — Take the Waddell-Entz machine ? 

Mb. Cubtis: — Have you tried it on a multipolar? 

Mb. Leonard: — Yes. 

Mr. Cubtis: — How much have you weakened the field ? 


Mr. Leonard: — The same as here. From zero up to the full 

Mr. Curtib: — How much current did you put through the ar- 

Mr. Leonard:— Enough to lift 50 tons on a traveling crane. 
It is a 40 H. p. motor. 

Mr. Curtis: — How much above its normal current on the ar- 
mature 'tf 

Mr. Leonard: — About double. 

Mr Curtis: — And it did not spark? 

Mr. Leonard. — Not a particle. 

Mr. C. O. Mailloux: — I might mention a bit of experience 
whic^h is a propos of this very subject and may tend to throw 
some light on it. I have found that a generator will be able to 
carry a much heavier current when worked at lower potential 
than it normally would if it were working at its normal electro- 
motive force. The particular machine was a railroad generator 
having lower potential than usual, about 300 volts, and capable 
of carrying some 800 amperes. The armature insulation was 
found very low when tested, apparently because the armature 
wat» not suflSciently baked when finished and the shellac was not 
quite dry. There being no better way of drying or baking it, 
we determined to heat it electrically, by making it generate a 
very strong current. The method, by the way, proved quite suc- 
cessful, and the armature in due time became quite dry and the 
insulation increased until it became perfect. In order to avoid 
undue potentials that might cause a leakage through this low in- 
sulation, the machine was run at as low a potential as we could 
possibly run it, in order to get the necessary current. In other 
words, what we endeavored to do was to run the very heavy cur- 
rent through the armature at the lowest possible potential at 
which we could generate it, so as to have plenty of heating ejBEect 
and very little potential that would cause any leakage through 
the armature or to the core. For this purpose we proceeded in 
two ways, first by reducing the speed of the engine which ran the 
dynamo to the lowest practicable speed. But as it was a Corliss 
engine, or an engine of the slow speed type, which does not ad- 
mit 01 being reduced in speed very greatly without danger of 
** stalling" at the dead centre, we had to make the rest of the 
reduction by reducing the field of the dynamo. It was a com- 
pound machine, and we reduced the current through the field 
until we had only about one third the number of ampere turns 
and possibly less. We could not measure it exactly, because 
the amount of current was rather small and the ampere meters 
we had at our command would not give us very great precision. 
At any rate, the potential was reduced to something like 50 volts 
from 300. Under these conditions we found that we carried not 
only the full current that the machine would normally carry at its 
iuli potential, but we could carry a good deal more, 15 or 20 

18d4.] DISCUSSION. 89 

per cent, more, without any sparking at all, poeeibly less than 
with full load at normal e. m. f. I think that the explanation 
given by Mr. Leonard is fairly consistent witli the facts. The 
auionnt of energy that is concerned in the reversal is small, be- 
canse the voltage is veir small, so that the energy involved is a 
very small quantity. Under those conditions the neutral point 
seems to be much wider. It is quite evident that with the full 
p<>tential there would be a much greater difference of potential 
per segment of the commutator. At full e. m. f. the difference 
of potential between the first two segments on either side of neu- 
tral line, multiplied by the current carried, would have been a 
greater amount, and naturally would iiave caused a greater dis- 
turbance at the commutator. I simply mention this fact to ver- 
ify the observation of Mr. Leonard that it is possible to run a 
machine with a much higher current than the same machine can 
be run at a higher potential. 

Mb. Nelson W. Perby :— I would like to refer to the seventh 
condition mentioned by Mr. Leonard : " The retardation of the 
" load in coming down grades, and in stopping, shall be effected 
" by converting the motors into generators, which shall feed back 
" current to the line, and thereby assist the power station in ope- 
" rating other locomotives." Mr. Sprague tried some experi- 
ments, I think, on the Third Avenue Railroad some years ago, 
to determine what portion of the energy consumed was usefuilv 
employed, or employed in operating, and how it was employed. 
My recollection is, that he found that about 83 per cent, of all 
the energy consumed was utilized in overcoming gravity and the 
inertia oi trains, leaving about 17 per cent, for traction. It is 
evident, if we can accomplish this and throw the energy absorbed 
onto the line, it will accomplish a very great economy, because 
on a hilly road there is as much down hill as there is up hill, 
and a car stops as often as it starts ; so that theoretically we have 
got a road reduced to a level and the trains of constant speed, 
not varying. Now the question is, whether Mr. Leonard has ac- 
complished this in his plan. Observe, that on each car, what 
may be called the prime mover is a synchronous motor. A 
aynchronous motor does very little useful work unless it is in 
step with the generator. Suppose we are operating that syn- 
chronouB motor as an alternating current generator. Its speed will 
vary with the speed of the car. If we are checking our car it 
goes from maximum down to zero. Now, the second car that is 
on the road, in order to do any useful work at all, would have to 
keep step with the generator. But we see that it is changing in 
the number of its alternations per second constantly, so that it 
seems to me that it would give no benefit at all, probably, to the 
second car, because that synchronous motor would have to keep 
in step with the other, because it is constantly going down to 
zero. Then the question comes up, can he throw any energy on- 
to the line in that way ? He has got to have an electromotive 


force which is equal to that of the line. Otherwise he can 
throw no current onto the line at all. Everybody knows that 
in coupling up generators in multiple arc, in our generating 
stations, we have got to take great precautions conuecting across 
from the armature of one to the field of the other, so that one 
will not drive the other as a motor by a slight increase of electro- 
motive force. There is only one condition in which he can 
throw energy onto the line by reversing his synchronous motor, 
and that wm be when the armature is revolving at such a speed 
by producing 500 volts, if that is the voltage of his trolley wire. 

Mr. Sprague has also said that by reversing the motor and 
converting it into a dynamo he conld throw energy onto the 
line, but f do not see how he can, unless that motor generates an 
electromotive force of 500 volts. In series arrangements, if you 
reverse your motor and make a generator of it, it will contri- 
bute energy to your line up to the last turn of the armature. 
But on multiple arc I do not see how it is possible to throw it on 
except in a very special case. 

Mr. Leonard : — I think that Mr. Perry has not understood the 
function of the synchronous motor. He speaks of it as varying 
in speed from zero to full speed. A synchronous motor is neces- 
sarily running at a synchronous speed constantly in one direction, 
and there will be a theoretical change in speed between its per- 
formance as a generator and a motor, but it will be very slight 
indeed. When the locomotive is being brought to rest it will be 
exactly equivalent to having two alternating current generators 
operating in multiple with each other, each producing current as 
a generator. But it will perform just as when a motor, and con- 
tinue in synchronism and at the same speed as the generator. 
There is a theoretical slight falling off. There is not exactly a 
falling off in speed, even then. The armature moves a little in 
its relative position in the field. But the number of waves per 
second is the same as before and its speed will be identically tnat 
of the generator. As regards putting energy back into the line 
as against the voltage of the line, I agree with Mr. Perry, that it 
is impossible for any single motor on the multiple arc system to 
put energy back against, we will say, 500 volts, down to a con- 
dition of rest, because your electromotive force will necessarily 
fall below 500 volts before you come to rest, and at such a time 
as^that you can put no energy back to the line. Therefore it is 
necessary to have something in the shape of a transformer, so 
that as your energy which was originally of 500 volts falls down 
from 500 volts to zero, it will by means of some intermediate 
device have that energy continuously transformed up to 500 volts 
and a little higher in order to send current back into the line, 
which is what we have in this arrangement. If you take this 
final motor and drive it so as to produce 20 volts, you can make 
the first machine there prodnce the full electromotive force that 
it receives from the line, and more. It would produce much 

1849.] DISCUSSION. 91 

more except for the retardation of its armatare by the work that 
it is doing in feeding current back. We take 500 volts from the 
line to the first motor and through the transforming arrangement 
we produce 20 on the final motor. We can reverse that. We 
can produce 20 by the last one as a generator and have 500 feed- 
ing into the line from the first one operating as a generator. 

Mr. Pebrt : — Mr. Leonard misunderstands what I said in re- 
gard to tlie synchronous motor. What I meant was that you are 
driving through a connecting link — through the momentum of 
the car acting on the car wheel. Now, as Uie car slackens up the 
armature of your synchronous motor, now converted into a 
generator, will slacken up. 

Mr. Leonard : — No. You have not understood the arrange- 
ment, Mr. Perry. The final motor in the diagram, l, connected 
with the wheel is the only one whose armature has any relation 
to the speed of the car. It is connected with tlie wheel of the 
car and it will slow down and speed up as the locomotive does. 
The other two will run continuously at a constant rate of speed, 
regardless of whether the locomotive is at rest or in motion. 

Mr. Perry:— The middle machine is excited then by the cur- 
rent generated by the street car motor, is it not? 

Mr. Leonard: — No. It is excited as shown in the diagram 
there. There are various means of accomplishing that. 

Mr. Perry: — As the armature of the car motor slackens down, 
the electromotive force of your generator, of your motor, will 
slacken down and its speed will be reduced, and it is connected 
with the armature of your synchronous motor, is it not? 

Mr. Leonard: — Since they are both motors and generators at 
different times, which machine do you refer to ? 

Mr. Perry:— As the armature l slackens down, the annature 
of K will slacken down. 

Mr. Leonard: — No, the armature of k continues at a con- 
stant rate of speed under all conditions. 

Mr. Perry :— Not if it is run by n. 

Mr. Leonard : — It is only run by n when n furnishes electro- 
motive force sufificient to operate k at its full speed and tends to 
drive it faster. 

Mr. Perry :— But under all conditions constant? 

Mr. Leonard: — That is the only condition under which it 
will come to rest. 

Mr. Perry : — Now as to the svnchronism, the motor which is 
supposed to be helped along will have to keep step with that. 
You admit it will not feed back unless it generates an electro- 
motive force of 500 volts ? 

Mb. Leona^rd: — Yes, but I did not assume that the speed of 
that machine k is going to change at all, practically speaking. 

Mr. Perry : — It will not be when you are running that as a 
generator, because the electromotive force of l will vary with its 


Mr. Leonard : — There is no mechanical connection between l 
and K. When I have a low electromotive force produced by l 
as a generator, and supply to the armature of k as a motor, the 
field of K is very weak — ^so weak that the low electromotive 
force of that armature does run it at its full speed still. 

Mr. Pkrry : — I see. 

Mr. Curtis : — In order to have the electromotive force of the 
motor L — in order to have h a generator, when that car begins to 
slow down, it is necessary that the field capacity of l should be 
capable of being enormously increased, isn't it? 

Mr. Leonard : — No, sir. The reverse is equally true, that you 
can make it a generator by weakening the field of k, which is 
what is done. 

Mr. Curtis : — Suppose it is a generator, suppose you are go- 
ing down hill and you want to have l generate current and feed 
it to the line. When you are running at full speed it will do 
that all right of course. But as you merely reduce your speed 
and net down to say about 25 per cent, of your original speed, 
in order to make that feed into the line, it is necessary to increase 
the speed. 

Mr. Leonard : — No, sir. When you come to slow down you 
do it by weakening the field of k. 

Mr. Curtis:— \ on do not have to feed against 500 volts. You 
feed against a correspondingly reduced voltage. 

Mr. Leonard : — 1 es, considering the flow of current from l 
to K. But as regards the flow of current from h to the line, that 
is continually 600 volts. 

Mr. Curtis :— rBut you weaken your direct electromotive force 
from K Just as fast as l does ? 

Mr. Leonard: — Yes. Perhaps after this discussion the opera- 
tion of this apparatus can be better understood. When that 
motor was running at fnll speed, and the field rheostat horizon- 
tal, to bring it to rest I broke the fleld of k rapidly but gradually 
through a large number of steps. We will say that k was pro- 
ducing 250 volts and the counter electromotive force of l was 
perhaps 240. The moment I began to weaken the field of k, the 
momentum of l kept its counter electromotive force up tempo- 
rarily and the counter electromotive force rapidly became larger 
than the impressed electromotive force of k. Consequently the 
current went back into k which was retarded in its efforts to go 
faster by the fact that it is driving n which becomes a generator 
to feed current against the line. 

Mr. Curtis :— In one case k is feeding a surplus of electro- 
motive force to L with a varying amperage and rising electro- 
motive force and diminishing amperage, and when you are 
slowing exactly the reverse takes place, tnat is l feeds k. 

Mr. Leonard : — That is right. 

Mr. Curtis: — ^What net result of eiBciency have you secured 
as compared with a rheostat control ? Take a case, for instance, 

1894.] DISCUSSION. 08 

where you are operating a traveling crane under ordinary cir- 
cumstances, constantly starting up and reversing, and so on. 

Mb. Leonard : — Well, the efficiency of a series motor that is 
used on a traveling crane by the rheostat methods is practically 
proportionate to its speed. The field is saturated by the mini- 
mum amount of current that any load requires. There is but a 
slight change of field strength from the current required to 
handle the lightest load and the current required to handle 
the largest load. Consequently the field is continually satu- 
rated, and if it is saturated, the counter electromotive force, 
which is directly proportioned to speed, is the measure of effi- 
ciency. Consequently, theoretically my efficiency would be iden- 
tical with theirs under the condition or full speed and would be 
ten times as great at one-tenth speed, twice as great as theirs at 
half speed, etc., and the tests made by William Sellers & Co., of 
Philaaelphia, who are using the method, show that that is borne 
out exactly in practice. Every loss that was anticipated was 
exactly where it ought to be, and there was no loss and no result 
which was contrary to what was expected. 

Mr. Curtis : — What I meant to ask is what is the net result on 
a thing like a traveling crane of using these three pieces of 

Mb. Leonard : — ^Well, the amount of energy saved, which 
would otherwise be wasted in the rheostat, may not be a very 
important factor. Of course it is all saved, whatever it is. 
There is no waste in this. 

Mr. Curtis : — Have you made any test to show that ? 

Mr. Leonard : — Yes, but I cannot tell you what the efficiency 
is except by involving the speed. The efficiency in this system 
— barring the fixed losses of C^ R in the armature and the 
excitation of the field and the friction, its efficiency is constant 
regardless of speed. 

MB. Curtis :-^Tou have no figures then of the net advantage 
of that mode of controlling ? 

Me. Leonard: — No, I have not any at my tongue's end. The 
test made by William Sellers & Co. was this: They placed on the 
floor of their shop a jack-shaft running at about 360 revolutions 
a minute, upon which they placed a Drake and also a large fly 
wheel of a punching machine which had about four feet diameter 
and about five inches square of metal in the rim. The jack-shaft 
was driven by a ten horse power 220-volt Sprague motor, whose 
current normally would be about 40 amperes maximum. This 
fly wheel was then driven at full speed in either direction and 
reversed at will. The biggest duty that it had, probably, was in 
accelerating and retarding that fly wheel. When it was at full 
speed in one direction, and while the brake was ojS, and therefore 
the effect of the momentum would be a maximum, the field con- 
troller of the generator was instantly reversed. Then the en- 
deavor of the motor was to reverse, but the fly wheel insisted on 


its going forward temporarily as a generator! Finally the gener- 
ating action was sufficient to cause the motor to be broae^ht to 
rest, and then it started ap instantly to accelerate the fly wheel to 
full speed in the other direction, and there was an entire absence 
of sparking. At that time of reversal of the motor armature, 
and at the time when the feed was first reversed, the armature 
•current was 102 amperes while the rated full load current for the 
motor was 40 amperes. 

The feature of the method, which in the case of traveling 
<;rane8 makes it a point of advantage, is not the amount of cotd 
that is saved or the elSect of fluctuating load on the engine so 
much as it is nicety of control by this mechanism. No brake is 
used in handling a load. The retardation is effected electrically. 
That same thing is applied to electrical elevators. When 1 first 
introduced it both William Sellers & Co. and Otis & Co., who 
are using it, said that they were not at all inclined to use this 
method tor braking, because while theoretically it might be all 
right they had not had confidence enough in it to retard fifty 
tons with it while running above the workmen in a shop, and in 
the other case to stop an elevator full of people and moving 260 
feet a minute. But in normal practice they are using it without 
any mechanical brake at all, because the braking action in this 
device is far superior to what can be gotten by a mechanical 
brake. A mechanical brake should be applied with the maxi- 
mum torque at the beginning. We are all familiar with the way 
a street car operator will put his brake on — very hard at the be- 
ginning and release it a bit as the car slows down. The braking 
torque should be a minimum as it comes towards rest. With the 
ordmary brake shoe it is a minimum at high speed. In this in- 
stance, the amount of current for the reversal of this fly wheel, 
the retarding torque is 102 amperes in a constant field in the 
first instance, and as it came to rest it was gradually reduced to 
almost nothing. So that that the effect of it with a moving load 
is extremely smooth, and far more smooth than can be accom- 
plished by retardation by a friction brake. 

Mb. Curtis: — How much fiuctuation do you find that that 
makes in the primary current? 

Mft. Leonaed: — Very little. The primary current in any case 
I have seen is a maximum, with minimum load at full speed. 

Mr. Curtis: — But when you reverse, dont you get an increase 
in the maximum ? 

Mb. Leonard: — No, we get a very large current in the sec- 
ondary at that time but a correspondingly low voltage. I re- 
versed it repeatedly there, and the minimum speed represents 
the minimum current, from the supply line, under reversal or 

Mr. Curtis: — It can put an additional load on the generator, 
can it not — the primary generator of your system, the genera- 
tor connected with your alternating motor? 

1894 ] OrSCUSSIOK 95 

Mr. Leonakd : — It puts a very large current on that, but that 
larffe current is produced by very few volts. 

Mr. Curtis : — I understand. But doesn't it rise above the nor- 

Mr. Leonard : — Do you mean tlie full load ? 

Mr. Curtis : — When you reversed this fly wheel, for instance, 
what were you feeding with — an alternating current? 

Mr. Leonard : — No, a continuous current. 

Mr. Curtis : — And it did not affect the generator there at 
all ? It did not affect the motor that you fed from your primary 
source of current ? 

Mr. Leonard: — I do not quite follow you there. But per- 
haps I can answer your question in this way. Supposing we were 
running at full speed under a brake load, for instance. We might 
have 40 amperes taken from the line If we reverse the motor 
that supply current would come down gradually to zero and then 
go up again to 40. When we are reversing and have no volts 
there are no amperes on that circuit. 

Mr. George Hill: — The paper starts with the statement: 
*' Let us suppose that we are called upon to act as engineers for 
*' a steam railway desiring to operate its line by electric locomo- 
*' tives." This, it seems to me, removes the paper altogether 
from the realm of theory, and brings the method of operation 
down to the question of dollars and cents. We already have in 
our capital account the cost of machines that will carry a pas- 
senger from A to B with a certain expenditure of coal. The 
change then must be accomplished in such a way that the inter- 
est on the capital account shall be less than the cost of the fuel 
consumed by the steam locomotive, plus a certain amount for in- 
terest, repairs, depreciation and things of that sort. This is a 
question that the paper does not in any way touch on. It seems 
as though it were a matter of course that the capital account for 
such a complicated installation as is here given must give an in- 
terest account very largely in excess of any possible saving of 
fuel. So far as I can learn, the question of restoring energy to 
the line is one which works out very beautifully, theoretically ; 
but as a practical result it is represented by zero, and in the pre- 
sent case is of no importance since the power costs nothing. The 
efficiency called for under heading 9, 50 per cent, seems to me 
to be very much in excess of anything that is practically possible. 
If we take the successive steps given on the diagram, Fig. 1, 
page 77, and assign an efficiency of 95 per cent, to generator a, 
and 95 per cent, to the transformer b, 80 per cent, to the line, 
which IS Mr. Leonard's own figure, and then 95 per cent, to 
transformer d, 90 per cent, to the line f, 90 per cent, to the 
synchronous motor h, 90 per cent, to k, 80 per cent, to l, and 
then 80 per cent, for transmission, we get a resultant efficiency 
of 32.2 per cent., which is somewhat below the 50 per cent, 
limiting condition given by Mr. Leonard. If instead ot that we 


take what is commercially probable, and run our efficiencies back 
90, 80, and so on, we get 16 per cent., which is probably correct 
for the best possible commercial conditions. So tliat if we were 
acting as engineers for a line, the first thing we could do would 
be to figure up our capital account and see whether the entire 
cost of fuel wnen capitalized would afford a sufficient amount to 
install any apparatus, and then we would be in a position to take 
up the question of efficiency, when we would find that we would 
have to nave an efficiency higher than any apparatus operating at 
the present day, to get as high as 40 per cent.; while if we took 
usual conditions as a guide we woula probably run down some- 
where around 10 which is only a little bit better than the abso* 
lute efficiency of the steam locomotive. Looking at the ques- 
tion from the very broad point of view of whether or not, in 
order to improve the character of the service, increase the speed, 
or for any other desirable change, we should advise a change, we 
would at once be confronted with a host of other difficulties. No 
one can be more desirous of seeing electric appliances brought 
into general use than myself, nor would I desire to take the posi- 
tion of captious criticism of anything proposed, but I do tnink 
that we should bear in mind the intensely practical nature of the 
age in making suggestions, and develop them along the lines in 
which we can reasonably expect success. Mr. Leonard's method 
of motor control under the conditions of operating printing ma- 
chinery of various kinds, electric elevators under special condi- 
tions, cranes and other similar uses, is, no doubt, much the best 
that we know of at the present time. Whether it is the best for 
railway operation remains to be seen. The plan proposed, cer- 
tainly contains many unknown quantities, and they should be 
solved before an attempt is made to apply the system. For ex- 
ample, what would happen to the syncnronous motor if the trol- 
ley should accidently leave the line ? How would we insulate the 
20,000 volts? Why not put the synchronous motor and continu- 
ous current generator in power houses, say 15 or 20 miles apart, 
and send 50u-volt continuous current through the line instead of 
the alternating current, thus putting our complicated machinery 
where it could be attended to, having on the car nothing but a 
motor. If our power costs nothing, the further Question would 
come up of the desirability of using Mr. Leonard s device since 
it is strongest from the fact that it is economical in its consump- 
tion of power, and power, in the assumed caae, is valueless. 

Me. Charles IIewi'it : — There is one point — I do not know 
whether Mr. Leonard has brought it out in this paper or not, but 
he haB, in describing this method, intimated that by using it and 
avoiding certain fluctuations which are characteristic of street 
cars, that he can use smaller units. Now the size of the unit is 
limited rather by the grades on a road than it is by the starting 
effort, and the same would apply to a train that is true of a street 
car. Any machine that will overcome grades at satisfactory 

1894.] DIISCUSBION 97 

speeds on ordinary roads ought to be sufficient and will be suffi- 
cient to start the car. Therefore, as far as the units on the train 
itself are concerned, we cannot save anything in their capacity. 
With the old type of apparatus on street cars something might 
l)e saved perhaps in generators, but I do not see that it can in 
motors. On a steam railroad of 100 miles in length I do not be- 
lieve we can save anything in generators. The two problems of 
the steam railroads and the street car roads are entirely different. 
The conditions are entirely different. In the first place I think 
we are all satisfied that we cannot compete with the steam loco- 
motive, except for very high speed service. Until we are ready 
to put a service of 1 25 miles, say, or something above what we 
can do regularly with steam, I do not think any of us will at- 
tempt to compete, so far as original cost of installation or cost of 
operation is concerned. But tlie hope for electric traction on 
long distance roads is in high speeds which cannot be obtained 
with a reciprocatin£r engine, ana on such roads as that stops are 
very infrequent. 1 believe Mr. Crosby has shown in one of his 
articles that we cannot afford to stop a train running at that 
speed in distances less than say 100 miles. Well, the starts and 
stops on such a road as that would be a matter of insignificance ; 
so that in considering such an apparatus as this, we must com- 
pare it only with other electric systems which we can use, such 
as the direct application, as we use it in the street car, or some- 
thing developed from that— some simple arrangement. We 
would have to leave out of account the question oi economy and 
compare this with the application of simple apparatus, and in 
that case it becomes a question as to wnether the advantage 
gained in starting and stopping once in 100 miles would compen- 
sate for the extra cost of such an arrangement a& this. 

Mr. Leonard : — The gentleman who first spoke, figured out 
the efficiency. He called attention first to the opening para- 
graph, but he forgot to read the next line following : " There 
exists a very economical source of power, possibly a water 
power." There is no intention, although I do not grant that it 
IS not possible — there is no intention in this paper to try to prove 
that the production of power by steam and its utilization in this 
way is going to be more economical than that of a steam locomo- 
tive. That is not the point. The point is that there may be 
instances where a very economical power, such as a water power, 
is running to waste and the cost of using it practically nothing 
after being once developed, and we are therefore putting that, 
and not coal, in competition with the present cost of steam, and 
furthermore the requirement of high speed service is probably,, 
as Mr. Hewitt has pointed out, going to be the means of bring- 
ing electric locomotives forward if anything does. No one i& 
going to change his equipment of steam locomotives for electrie 
locomotives merely in a hope of economy in their operation 
under usual conditions. It must be to accomplish somethini^ 


that cAnnot be done by a steam locomotive, or to use some kind 
of power which is so much more economical than coal that the 
net result is better. 

As regards tlie question of eflSciency, I went through the same 
steps in arriving at the figure 50 per cent, specified, as Mr. Hill 
did. But my figures were based upon commercial apparatus 
such as makers of apparatus of first-class type would be willing 
to guarantee, and I did not assume for large transformers of say 500 
horsepower an efiiciency of 95 per cent., nor an efliciency for large 
generators of 90 per cent. The fact is, that you can secure trans- 
formers of a size such as this, which will have a full load eflSciency 
of 97 or 98 per cent., and generators which will have an eflSciency 
of 95 per cent , and there is no reason for supposing that the 
motor L will have an eflSciency of 80 per cent. The eflSciencies 
as quoted by him were unnecessarily low. Taking the figures 
such as would be guaranteed by makers, and remembering that 
the motor generator has much less loss by virtue of friction than 
two machines ordinarily belted, etc., the result which I obtained 
ijvas an efliciency of 52 per cent, for the combined apparatus, 
even with 20 per cent, in the transmission line, but admitting, 
for the sake of argument, that it is 40 per cent., which may be 
80. still we were trying to operate a long railway 100 miles long. 
Now the question is, how are we to do it? And this paper is a 
suggestion in that line. Mr. Hewitt says we should use the 
simple method of to day. By the " simple method of to-day," I 
suppose he means 500 volts. 

Mr. Hewitt: — Not necessarily 500 volts. 

Mr. Leonard : — Well J do not know how bv any *' simple 
method of to-day " we are going to operate a railway 100 miles 

Mr. Hewitt : — I simply meant a motor built on the axle. In 
fact I have no definite plan in view, but I mean the development 
of some such plan as a simple device. 

Mr. Hill : — I should just like to call attention to the fact that 
in my statement for comparison I did assume that the fuel would 
cost nothing. I said that an engineer must necessarily compare 
the interest of the increased capitalization of the plant with the 
saving in fuel, which I think eflEectually meets Mr. Leonard's 
point. Concerning the efliciency which he gets, that is purely 
a secondary matter. 1 fiixd it, in practice, exceedingly diflScuft 
to get makers to guarantee machines for efficiencies ten per cent, 
less than I assigned here. 

Mr. Kennblly : — I would like to ask why, in the opinion of 
the last speaker, the practice of engineering for railroads should 
depart so widely from what has been the recognized practice in 
ocean locomotion. Consider, for example, the journey from Liv- 
erpool to New York — a saving of twelve hours in transit would 
■certainly not justify, on any basis of economy, the enormous in- 
crease in the volume of coal burned on the more rapid journey. 

18W.] DISCUSSJOI^. 99 

There could be no economical arguofieut for any steamship con- 
struction to reduce by a few hours the transatlantic passage, when 
it is recognized that the amount of coal burned per hour, and the 
engine capacity required, increase approximately as the cube of 
the ship's velocity. Nevertheless we find that experience, which 
is the safest guide in these matters, is continually urging on steam- 
ship builders, higher rates of speed and further coal consumption. 
Surely, if the electric locomotive will enable us to attain a higher 
speed than existing methods produce, the considerations which 
have justified the builders of ocean steamships in seeking for 
higher speeds at the expense of increased coal consumption 
should be equally influential in favor of the adoption oi the 
electric locomotive for land transportation. 

Mr. Mailloux : — There is one point that seems to have es- 
caped attention in this discussion. Assuming that we are able to 
convert the power back from the car axle to the line and that we 
finally get it to the line, what will it do there ? Those whet have 
investigated the problem of regulating water-wheels for railway 
purposes would certainly nqj have much use for it. Nor do 1 
think it would be of much more service where steam engines 
were used. If I am not mistaken, it has been found by actual 
experiment that the eflfect of restoring energy to the generating 
source in railway work is to interfere greatlv with the regulation 
of the generator, if not to make it entirely erratic, because, as 
we know, the curve of supply of current on railway service is 
itself extremely erratic. There are periods when the consump- 
tion is very great, followed rapidly by periods when it is ex- 
tremely small, or even zero What may be the eflfect of current 
being restored to line when there is no consumption on the cir- 
cuit ? We can readily see, since the energy must go somewhere, 
it will go back to the station, and will tend to make the engine 
" race," just as a corresponding increase of load would tend to 
slacken its speed. In a water-wheel we can do nothing but shut 
off the supply of water. Our devices at present are quite in- 
adequate to prevent the water-wheel from racing, even when we 
take the load oflf quickly, to bslj nothing of what it must do when 
we put a negative load on ; m other words, when we apply a 
force which tends to make it revolve without the application of 
any water power. We readily see that in the present state of the 
art, the question of restoring energy to a railway circuit, where 
the rate of consumption is at all unequal, is purelv visionary and 
impracticable, because there is no means of utilizing that energy 
in such a manner as to render it serviceable without introducing 
veiy serious causes of disturbance. It will only be when we 
have means of balancing the circuit by some means of storing 
energy in the circuit, or some portion thereof, that we shall be 
able to properly and satisfactorily utilize the energy restored. 

With regard to eflSciency, it may not be out of place to men- 
tion the fact that what we have to deal with in railway practice 


is not the efficiency of full load by any means ; that it is on the 
contrary the efficiency of a load whicn, when averaged for the 
whole day is a very small portion of the full load. 

Mb. Hkwitt:— !rardon the interruption. That applies on 
street cars and not on a long distance road. It would not apply 
even on a suburban road. 

Mb. Mailuoux : — Mr. Hewitt is correct on that point ; but the 
remark still applies to the line transformer l which would not 
work at constant load, unless the number of trains be always 
equal to the number of such transformers, and unless the trains 
are always under the proper headway to keep each section of the 
line and each transformer constantly loaded. 

Mr. Wm. Elmeb, Jb.: — I would like to aek a question. The 
author of the paper says, when the field is reduced to zero, the 
armature of the motor, being driven by the momentum of the 
car will send the current through the armature of what was be- 
fore the direct current generator, and that will drive the alter- 
nator. I do not see how it can act as a generator when there is 
no current in the field. 

Another point I thought of was, that supposing an engineer 
should be in danger of collision : he would suddenly throw his 
switch from one side to another, the generator would be thrown 
out of synchronism and the whole thing would be left dead ; and 
how can the generator be started \^ hen the engine is to be taken 
out of the round house in the morning ? 

Mb. Leonabd : — In regard to the question of the performance 
of the intermediate machine as a motor, if you are running under 
condition of full speed and you gradually weaken the field of 
the generator to zero, that field does not instantaneously reach a 
condition of zero, but goes down gradually, and the more it 
tends to go down the more current tends to go into it as a motor 
and tends to drive it fast, and the greater the braking action 
becomes upon the armature on the locomotive axle, because it is 
producing a very large amount of current in that constant field ; 
and, of course, that acts as a brake to stop it. I do not quite 
understand what the last speaker meant about throwing the 
alternator out of step. If the machine were running at full 
speed — the train— and the field of the generator were reversed 
so that the propelling motor of the train had a tendency to in- 
stantly reverse, the only result would be that the alternator, 
instead of running as a motor, would be driven as a generator 
to feed current to the line, but there would be no rapia change 
of load, nor would there be any excessive load on the alternator 
80 as to tend to throw it out of step. The intermediate machine 
would tend to speed up, but it would not speed up because it 
would be continually feeding current into the line which would 
be acting as a brake for itself. 

There are so many ways of bringing up a synchronous motor 
to speed without load that I did not indicate any particular 


method. One simple method would be, eliminating altogether 
the performance of the machine as an alternating current motor 
at slow speeds, to have a motor of perhaps two or three horse 
power connected to the alternating current machine, and a few 
cells of storage battery, which would run that little motor. Tliis is 
eliminating all alternating currents and showing one means which 
it is self evident would work. A few cells of storage battery 
would run a small motor, which would run the alternating motor 
up to synchronous speed. After it is in step it will run that 
same small motor as a generator to keep the storage battery 
charged and to excite the field of the synchronous motor. An- 
other method would be to use such a device as is used on the 
alternating current motor of the type of the Dahl Company. A 
third way would be to have the field wound for perhaps 50 volts 
and the armature wound for 500, and first connect it in series 
with the armature, in which case it would start up readily, and a 
switch could be arranged for connecting the commutator of a 
continuous current winding in the same field, to supply it when 
at full speed. There are half-a-dozen well known ways which 
are possible for starting an alternating current motor which is 
only to start under friction load, and which, when running at full 
speed, excites its own field. 

Mr. C. J. Field: — I came here to-night seeking information. 
1 think we have come to a time in electric railroad work where 
we have got to take these problems iip, not only on long 
distance transmission but in city work. We are having enor- 
mous investments of capital in cables and other means, and we 
have got to take up some method of higher tension, or some 
method similar to Mr. Leonard's of alternating current to do our 
work. What we ought to do is to try to get more information 
on the subject and fiSvance more. If Mr. Sprague, seven years 
ago, had objected to everything, as the majority have done 
to-night, I do not think we would be in the position with 
electric roads that we are in to-day. There are a number of 
points in Mr. Leonard's paper that are good, but there are quite 
a number of objections to oe cleared away. One is the question 
of insulating a single trolley circuit of 500 volts with the alter- 
nating current. Those of us who have had experience trying 
to insulate a direct current with 500 volts would want to go to 
some extraordinary means to take care of a grounded circuit with 
500 alternating volts. The proposed apparatus would go very 
well on a large electric locomotive ; where would it be put on a 
double truck 36-foot car? That would virtually be having a 
small central station in the car. I do not want to be taken as 
trying to criticize, but I want information. How much room is 
the apparatus going to take up to operate an ordinary 34 or 36- 
foot car, and vmere are you going to put it ? Furthermore, have 
we got sufficient advantages over every other means which are 
now being proposed, and with which some of the large compa- 


nies are experimenting and claim they are about ready to put, 
in — that multipliase motor ? Of course, the objections to tliat 
the carrying too high tension and reducing down with some form 
of rotary or other transformer is a question of several trolleys — 
other means, the rotary transformer and the direct current, which 
Mr. Leonard has objected to, but which, on a road of 100 miles, 
if we put iive or six of them along the line, distributing six or 
seven miles each way, seems to have many advantages if we are 
operating from a water power plant. 

Those are all questions that I would like to hear discussed 
more, for the reason, among others, tliat it happens at the present 
time that I am worrying over a problem of this kind — ^a road 
100 miles long which we have got to operate with electricity ; to 
get up about 7,000 feet elevation at a good deal less cost than a 
steam road can be built for, because you can take higher and 
steeper grades than a steam road could take, and thereby largely 
reduce tiie cost. We can operate our cars witli less expense man 
having a three or four dollar a day fireman, or engineer and lire- 
man combined. 

These are a few of the points I would like to present for your 

The President : — There is a gentleman here we would like to 
hear from — Mr. Woodbury, of Soston. I believe he is not a 
member, but I am sure the Institute would like to hear from 
him on this very interesting question. 

Mr. C. J. II. Woodbury : — Although I am here as a guest, I 
willingly avail myself of this opportunity of expressing my ap- 
preciation of the paper of the evening on Mr. Leonard's method 
of connecting motors with generators ; and in the consideration 
of this question I beg to depart somewhat from former speakers, 
who have confined themselves entirely to a consideration of 

Erinciples " Because," as Jack Bnnsby wisely concludes, " the 
earings of this obserwation lays in the application on it." 
I wish to call your attention to the results of the practical ap- 
plication of this method of coupling up electric motors in an in- 
stance where it served as a solution of the problem after other 
methods had failed, and that is in the application of electric 
motors to the operation of calico printing machines. Calico 
printing is done by means of a number of engraved cylinders, 
from four to eight inches in diameter and wider than the clotli, 
which press upon a large drum that carries the cloth under these 
rollers. This drum is covered by a belt of cloth about one- 
fourth of an inch in thickness, which is called the blanket, and 
the fact that these rollers are forced against the drum with great 
pressure renders this type of macliine a very difiicult one to 
start ; the conditions being analogous to the starting of a heavily 
loaded wagon on a soft road. 

The conditions of operation require that the printing machine 
must be able to run uniformly at any desired speed within its 

1894.) DI8GUISSI0N. 108 

limits of operation^ that it must be able to move the cloth a few 
inches, and that it mnet start and stop readily. The method of 
using a two-cylinder engine in the print room has been hitherto 
the best approximation'to the desired results. The obstruction 
of desirable floor space, the heat and dirt from the machine, all 
being especially objectionable in this place, were regarded as 
necessary evils. 

The reconstruction of a print works on the site of one that was 
burned gave an opportunity for an attempt at the application of 
an electric motor to driving a machine. After other methods 
failed, that devised by Mr. Xeonard was successful. The motor 
is placed on the mezzanine floor of the print room, on what is 
known as the platform, and is controlled by a hand- wheel and 
switch at the front of the machine. It has been in operation 
over two years with the most satisfactory results. The cloth can 
be moved as little as one inch if necessary, and the speed can be 
increased to any desired result by uniform gradation without any 

The ability to stop and to start quickly, as well as to run the 
machine in such a unifonn manner also allowed for its operation 
at a greater speed, and I have been informed that the production 
of this machine exceeded by one- third that of the other machines in 
the room. When it is considered that the value of a print works 
plant is at least flfty thousand dollars per machine, this increase 
m productive capacity is of great importance. It is said that 
when the question of introducing a motor into these print works 
was first considered, it met with opposition on the part of the 
help, and that afterwards when the practical results were reached, 
those employed at other machines wished that these also should 
be driven by motors In fact, as a result of the experiment, one 
of the firm has made the statement that if he were to build a 
new print works he should use electricity entirely for the distri- 
bution of the power, notwithstanding that the value of exhaust 
steam is greater in print works than m almost any industry. 

Mk. Joseph Sachs: — One of the points made in the paper is, 
that there should be no moving apparatus between the station and 
the car. Is not the objection to placing the apparatus, that is, 
the additional moving apparatus, upon the car, quite as great 
as that to placing the rotary transformer that we would use in a sys- 
tem of the kind, along the road i A rotary transformer does not 
take very much attention, and we are not limited to placing these 
transformers at a distance of exactly two miles apart. The loca- 
tion of the transformer along the line, transforming the alternating 
current, from a high tension alternating to a 500- volt direct cur- 
rent, which would be fed direct to the trolley wire, would be, per- 
haps, more efficient than the method illustrated, in which we have 
at least one more transformation to be met with than in the 
method spoken of. The location of a 500-horse power or more* 
synchronous alternating motor, and a constant current generator 
of equal power upon a car, with the necessary devices for starting a 


sjnchronous motor, would certainly take up a great deal of room 
and require considerable attention, and I believe that although 
the system proposed by Mr. Leonard of regulating is certainly a 
very practical and feasible and economical one, we are to-day ob- 
taining very economical results with the series parallel arrange- 
ment, and we can certainly have some other form of keeping a 
constant field of the motor and varying the field and torque oy 
the electromotive force and current passed through the armature. 
It is true that the location of transformers alon^ the line would 
slightly increase the first cost of plant, but would not the addi- 
tional simplicity of such an arrangement, and perhaps the some- 
what higher etticiency of placing the apparatus in that position, 
make it advisable to leave off everything excepting the actual 
driving motors, from the locomotive ? Certainly where we have 
a very long road of say one hundred miles and very few trains 
moving thereon, the devices proposed by Mr. Leonard would 
certainly be most advisable to be used. But where there 
are a comparatively large number of trains moving on a long road 
1 should think the more acceptable plan would be to make the 
transformation from the alternating to the direct current outside 
of the moving locomotive. It must be remembered that a road 
of this kind would most probably be operated at a high speed 
allowing of very few stops in the distance specified. The regu- 
lating apparatus would, therefore, not be used very frequently. 
I think, furthermore, we are not absolutely limited to one con- 
tact but that two wires can \ery readily be used, and some 
form of motionless transformer with a multiphase current can be 
utilized without the various rotary transformers that would be 
necessary in a single phase alternating system. 

The f^REsiDENT: — Mr. Leonard will close the discussion unless 
some other member wishes to speak. 

Mr. R. N. Baylis : — In view of Mr. Curtis's demand for spe- 
cific figures on efficiency and in regard to what Mr. Hill and 
others said afterwards, it might be interesting to give a figure in 
the case of an actual test on that arrangement. About the time 
this method of regulation was brouglit out I had occasion to 
make a test of it and was very mucli surprised at first at the 
value of the efficiency obtained. The arrangement which I had, 
put the apparatus under very unfavorable circumstances. I had 
two ten horse power motors, one used as a motor and the other 
as a generator, and a five horse power hoist which had a double 
reduction gear. There was a prony brake used on the drum, so 
that it made the apparatus something like that here exhibited, 
and with all that gearing and with the full load on the drum, 
and the rheostat so arranged that the speed of the motor, and the 
speed of the five horse power motor — which was normally about 
1,500, was about 190 revolutions, the efficiency obtained was 
about 70 per cent.; — it was 69 and a fraction per cent. This was 
the total efficiency from watts supplied first motor, to brake horse 
powjr output of hoist drum, and was certainly very high for such 

1894.] DISCUSSION. 105 

an arrangement as that, considering all the gearing. Regulating 
to the same amount with an ordinary rheostat on series would 
probably have given forty per cent, or less efficiency. 

The Fbesident : — If there are no others who wisli to speak, I 
will call on Mr. Leonard to close the discussion. 

Mr. Leonard : — One point that I made a memorandum in re- 
^rd to, was Mr. Field's statement relating to the possible objec- 
tion that might arise due to the difficulty of insulating a 500-volt 
alternating current. I had assumed that there would not be any 
particular difficulty in insulating that pressure. But it will be 
evident that there would be no difficulty — it will make no altera- 
tion in the arrangement, and it will be perfectly feasible to 
reduce the pressure to any voltage that will be desirable, and the 
limiting feature of that of course is, that if you have less volts 
you have more amperes to carry through your contact. Of 
course if you are going to deliver energy of 500 horse power, if 
you have low volts, you must have amperes correspondingly large. 
I supposed that 500 would probably be the best, because 500 
volts, as I believed, was the maximum that it would be safe to 
have in a bare conductor overhead. 

As regards the question of where we will dispose this appara- 
tus, I have not made any practical tests of any kind with this 
apparatus upon railways. It is evident that until a considerable 
amount of money is available to be spent in tests of a compre- 
hensive nature for railways, it is idle to take it up. 

The last paper I read on this subject was relative to the appli- 
cation of it to street cars on existing lines, and the objection was 
raised to it which Mr. Field has raised, that there would be diffi- 
culty in disposing of the motor generator on any ordinarjj^ street 
car. In the case of a locomotive there is no such objection. 
There is plenty of room on a locomotive for the motor genera- 
tor. You neecl the weight of the motor generator. If you do. 
not have the motor generator, you will have to put an equiva- 
lent weight in the shape of cast iron on the locomotive to get the 
weight that is required for traction. I purposely in this paper 
dodged this question of where you will put the apparatus, by 
providing a place that is big enough to put it in. 

As regards the question of whether it would be preferable to 
have the sub-station on the locomotive or the sub-station along 
the line, it seems to me there is every advantage in having the 
sub-station on your locomotive. In tne only prominent experi- 
ment that has been made yet on electric locomotives, the whole 
central station is on the locomotive ; that is, Ileilmann's locomo- 
tive where he has his coal and water boiler, and engine, and 
dynamo and motor all on board. I notice that he is able to 
operate and run 75 miles an hour and pull 14 cars back of him, 
with every prospect of high speed work. 

As regards the point of comparative merit of putting the 
transforming arrangements on the locomotive or along the line, 


it is evident, if tliey are along the line, they are §oing to require 
care. If they are in motion they require additional operators, 
whieli would be avoided if they are on the locomotive. With 
my fiystem you have nothing between your source of power and 
your locomotive, about which your engineer hae any question 
whether it is moving or whether it is not. lie knows that when 
Auf apparatus is all right, that everything back to the central 
station is probably in good working condition. There are not a 
lot of rotating transformers and all that which must perform in 
order to be sure that he is able to go. 

One of the most important pomts is this: The locomotive 
carries in itself sufficient energy to take care of its own train at 
any point on the road. But if you have a sub-station along the 
line the sub-station must be of such a size as will enable it to 
provide power sufficient for the operation of, perhaps, two or 
three times the usual maximum load because of trains that may 
perchance he upon that section at one time. Every one of those 
sub-stations must be big enough to take care of this unusual 
maximum load. Therefore, your sub-stations must have a veiy 
much larger amount of horse power installed, than the amount 
installed "upon the locomotives when each locomotive is always 
taking care of its own load and no other load. 

Another point is, where you have them all on the locomotive, 

{row have tiie economy, not necessarily of stopping once in a 
mndred miles, as one speaker has said, but of taking advantage of 
down grades and effecting a saving of energy, which you would 
not have to any such extent in a sub-station. 

A still further point is that the apparatus, it seems to me, is 
much simpler to handle when all on board of one vehicle, than 
when part of it is in one place and part of it in another. 

As regards the restoration of energy to the line, I can only 
give the results of practice. It seems to me evident that there 
is every reason for having some kind of a device which will take 
advantage of the energy which is to-day wasted. The statistics 
which Mr. Sprague gave in the past, and which I have not heard 
challenged and presume are accurate, were that 59 per cent, of 
all of the energy in use upon the Third Avenue Elevated here 
was used in getting up speed — acceleration alone — and that 24 
per cent, was used in overcoming the grade. Now, if 24 per 
cent, is the amount of energy which is required in overcoming 
the grade — the lifting effect, entirely independent of the accele- 
ration and traction, certainly it Avill be worth considemble to 
save a large fraction of the 24 per cent., and any method which 
will restore that to the line will be beneficial, and on lines which 
have considerable grade, which is the kind of road that electric 
locomotives will be particularly adapted to, we will get a very- 
much more marked saving due' to this restoration of energy to 
the line than in such a road as the Elevated. 

There are no injurious effects in practice upon the engines and 

1894.] DlSaUSiSION, 107 

prime movers by virtue of restoring energy to the line by this 
method. That has been very clearly demonstrated in the case 
of traveling crane service and in elevator service, and where a 
very large amount of energy is restored to the original circuit. 
Of course, if you take a hypothetical case of a motor going down 
a steep grade and only one motor in use, and a water-wheel, or 
an engine, or something of that kind, which is going to have no 
other work to do, it is possible to conceive that the energy re- 
stored to the generator driving it as a motor might cause some 
little trouble m the central station. But that is not a practical 
condition. The practical condition is, that you do have more 
than one, and that you will never reach a period where the 
energy restored is going to make your engine run beyond its full 
speed, and even if it does tend to, the engine soon begins to act 
as a brake by virtue of the partial vacuum — a sort of pneumatic 
pump — it tries to pump air and it acts as a brake first-rate. 

[communicated Al-TEK AD.JOUKNMENT BY MR. (iE()R(}E P. LOW.J 

One of the first impressions received from Mr. II. Ward 
Leonard's paper on '' Iiow Shall We Operate an Electric Rail- 
way 100 Miles from the Power Station," is the fact that in the 
adoption of such a scheme, or, broader still, by the general adop- 
tion of alternating current as the energy for operating electric 
railways circuits, a long step in advance would be taken in re- 
lieving the prevalent msurauce idea that trolley circuits form 
"uncontrollable" hazards. A moment's reflection will show 
that 500 volts direct current is more hazardous to property in- 
terests than 500 volts alternating, in that the hazard of crosses be- 
tween an alternating current trolley circuit, and the various aerial 
circuits is gi-eatly reduced, if not almost eliminated by the self-in- 
duction of the various appliances in connection with such aerial 
circuits, and that the electrolytic destruction of water mains and 
underground metal work would be a thing virtually impossible 
of occurrence with alternating current equipment. The use of 
alternating currents for overhead trolley circuits is, therefore, to 
be ex>mmended from these points at least. 

A belief that this feature is of material concern to electric 
railway people and the public in the larger cities, is my apology 
in presenting so marked a deviation from the original theme. 
San Francisco, March 1 , 1894. 

The Pkesident : — Gentlemen, there are one or two other 
items of business. We have an application from Chicago to 
elect a local honorary secretary so as to pennit local meetings to 
take place. Of course I am aware of the fact that our rules re- 
quire this to be acted on by the Council. Mr. Caldwell, the 
gentleman who was chairman of the committee making the ap- 
plication^ made an endeavor to get the application before tlie 
Council at its meeting to-day. As I am very desirous that these 


meetings shall be held, and as I know that Council is desirous 
that they shall be held, in order that no time should be lost, I 
have taken tlie liberty of getting an informal vote from all the 
members of the Council here, and I am sure that you will author- 
ize the little irregularity. I will therefore announce that the 
Council appoints Mr. Caldwell as local honorary secretary, he 
having obtained, in accordance with our rules, 17 votes of the 20 
who have signed the report, as required by our rules. 

There is a final piece of business before the meeting, and that 
is any action that you may wish to take as to the report of the 
committee on changes in Kule 5 — ^the election rule. This re- 
port is signed by Mr. Herzog, Mr. Martin, and Mr. Upton. I 
am not quite sure as to whether we can act on it to-night under 
the rules. To amend the rales at any regular meeting a two- 
thirds vote of the members present is required, and written notice 
of the proposed amendment shall be given out at the previous 
meeting. If that has been done, I suppose these rules can be 
passed to-night. What is your wish in the matter. 

Mr. Phelps : — There is some obscurity in respect to the rules, 
the organic laws of this body, and I think such a matter as adopt- 
ing a cnange in the rules oi election ought properly to be left to 
the annual meeting in May. I suppose that this meeting might 
express its views in regard to the report as a recommendation to 
the general meeting. The election occurs but once a year, and 
a great many of our members who live at distant points seldom 
reach us except at the annual meeting, whether it be held in 
New York or elsewhere. We can hardly, I think, with any pro- 
priety vote upon any change in the election rules in respect to 
their effect upon the election to occur two months from now, and 
it seems to me it would be wise to defer any action upon tliat 
report until the general meeting in May. 

Mr. Leonard : — I move that this question be laid upon the 

Mr. Upton : — I think some action should be taken on this 
report of the committee in view of the coming election. The 
present amendments here are merely to make clearer the inten- 
tion of the former rules. This matter was brought up at the 
annual meeting and referred to a committee, and there was a 
general understanding that these amendmepts should be placed 
in the rules, and I think there should be a vote taken. Tiiere is 
no change from the spirit of the former rule. 

Thk President: — What is your wish ? There is a motion to 
adopt, and there is a motion to lay on the table. Neither motion 
is seconded. 

Mr. Burnett : — I second the motion to adopt. 

Mr. Phelps:. — I am wholly of one mind with Mr. Upton in 
respect to the desirability of a revision. I have no doubt about 
that whatever. But in view of the somewhat anomalous situa- 
tion in which we find ourselves, that is to say, with sonie doubt 


whether these monthly meetings at New York are the Institute, 
or whether the Institute is only the body of people convened 
at the annual meeting in May, it seems to me that we had better 
defer any change whatever in the election rules until May. Our 
whole organic law needs revision. It is in a somewhat inchoate 
condition. It would, I think, be wiser to let the forthcoming 
election be held under the old rules rather than to have any 
question raised hereafter whether this meeting had the right or 
not to deal with the election rules. 

The Secretaky: — There is one provision of the revised rules 
which it appears to me can be carried out. Under the proposed 
amendment of the rule by the committee, it says : " Opposite the 
" name of each nominee in each list shall be printed a number 
" indicating the number of nominations received by him, and a 
" suitable explanation of these numerals shall be placed on the 
" sheet." Tnere is nothing in Kule 5, nor in the existing rules, 
as a whole, so far as I know, to prevent this being done now. It 
would have been done last year, only, as far as I could iind out, 
it was not thought judicious to put the numbers there. But if 
the committee in its wisdom, or the meeting, or any person 
in authority deems it proper to put those numbers there, there 
can be no question as to the right of inserting them. In fact 
they were put in type last year and taken out. As this require- 
ment can be carried out under the present rule, it leaves nothing 
but the question in regard to the envelopes. 

Mb. Phelps: — I think it would be hazardous to meddle with 
the rules in the slightest particular; just as hazardous as it would 
be to adopt an important committee report at this time. It 
seems to me quite clear that we are bound to go on till the next 
election under precisely the same rules as we had last year. If 
we adopt the suggestion of the Secretary we might as well adopt 
the whole report of the committee and make all the changes 
suggested by the committee. I believe the motion before tlie 
house is the adoption of the report of the committee. 

The President: — There is a motion to adopt the report, and 
a motion to lay on the table. The motion to lay on the table is 
not seconded. Does anyone second the motion to lay on the 

Mb. Phelps: — I did not second it, as I understood the other 
motion had precedence. 

The President : — Then I will put the motion, if the meeting 
is readv for the question, to adopt the report of the committee 
on revision of the rules. 

The Secretary : — I would like to ask for instructions. Eule 
5 goes on to say that the nomination circular sent out by the 
Secretary shall contain a copy of this rule ; that is, a copy of the 
existing rule. Now, as I understand, that nomination circular 
when sent out containing a copy of that rule, is for the purpose 


of inf omiiug the members as to tlie nile of the Institute govern- 
ing elections, and they are supposed to send in nominations in 
accordance witli Rnle 5 as sent out by the Secretary, whicli has 
already been done. Now if we adopt this amend^ rule, have 
we got the rieht to change a rule that has already partially gone 
into effect and has been nromulgated under the lately existing 
state of affairs i That Rule 5 as it existed, has gone out to the 
whole membership, and under that the election machinery has 
proceeded. My opinion in regard to this is that having promul- 
gated this rule as it stood we have no power to institute another 

Mr. Phelps : — Will the Secretary read Rule 5 again. 

The Secretary : — The paragraph that I referred to is as fol- 
lows : — " During the first weelc m February of each year the 
" Secretary shall mail to each full and associate member of the 
" Institute a list of members ; a list of the offices to be filled at 
" the ensuing annual election in May, giving the names of the 
"incumbents, and a copy of this rule, wifli the request that 
" nominations, propositions and suggestions as to desirable candi- 
" dates be made promptly and prior to March 1st." Now that 
had to be done according to the rule. I liold that the sending 
out of that rule to the membership is their law for the election. 
Copies were mailed the first week in February. 

Mr. Burnett : — I withdraw my second. 

Mr. Phelps : — Now tliat rule has been sent to all tlie mem- 
bers of the Institute by the Secretary, and that reinforces my 
point that no variation in the rule should be made between now 
and the election. 

The President : — The gentleman who has made the motion 
has withdra\^Ti it. 

Mr. Phelps : Tlien I second the motion to lay on the table. 

The motion to lay on the table was carried. 


Incomplbted Work of the International Electrical 
Congress of 1893. 

The following circular letter lias been forwarded to the 
chairmen of the sub-committees of the Institute. 

Philadelphia, February 23rd, 1894. 

A meeting of the Chairmen of the different sub-committees on Incom- 
pleted Congress Work, to whom was referred the consideration of suitable 
standards of light and illumination, was, in accordance with the notice al- 
ready sent you. held at the rooms of the American Institute of Electrical 
Engineers, New York, December 28th, 1893. 

At this meeting the proposals and enquiries of the various sub-committees 
were considered. 

It was decided to defer the formulation of any selected course of experi- 
mental work until such time as the progress made in any branch might 
render collateral organized aid an advantage. In the meantime, however, 
it was thought that the various suggestions which had been oflFered by the 
chairmen of the different committees should be exchanged among the local 
committees, not only w^ith a view of creating new interest in the work, but 
also for the purpose of indicating the direction alon^ which the various 
sub-committees would be likely severally to pursue their investigations. 

I therefore take pleasure in sending you an abstract of the written 
suggestions that have been made to me as general chairman of the 

(a.) Professor Brackett of Princeton University, (December 4th, 1893,) 
considers that a device which will enable a given source of light to be com- 
pared with a suitable standard, without the intervention of the eye as the 
means ot comparison, need not be despaired of. That such standard, if 
found, should be referable to the fundamental standards of length, mass 
and time. 

That for commercial purposes, a convention should be made as to the 
definite wave lengths that should be considered within the visual spectrum, 

(b.) Professor Charles R. Cross of the Massachusetts Institute of 
Technology, Boston. (December 25th, 1893,) believes that a measured area 
of a fiame should without doubt be a better standard than the complete 

Recommends that an endeavor be made to secure a constant and definite 
section of flame from oil or gas of definite composition, and that observa- 
tion be made to ascertain how far this may be subject to variation of 
temperature or pressure. 

Suggests that an examination should be made as to the errors which may 
attend the use of a chimney with the methven screen ; whether square 
chimneys could be used, or metal chimneys, or chimneys with an internal 
layer of lampblack. 

Recommends that the influence of sectional dimensions in the carbon arc 
upon its illumination should be observed, and that the capabilities of 
various photometers to compare lights of varying colors should be 

Suggests that the device of rotating an incandescent lamp about its axis 
of symmetry in the pjhotometer might be tried, to secure, if possible, a more 
uniform average horizontal intensity of emission. 

(c.) Professor Reginald A. Fessenden of the Western University of 
** Pennsylvania, (October 30th and December 9th, 1893,) suggests : 


That there is no hope of obtaining a satisfactory standard light for 
purpose of visual comparison in photometry, for the reason that the optical 
effect of any standard light is not generally the same either for two obser- 
vers at the same time, or for one observer at different times. 

He consequently recommends that all laboratory measurements of light 
should be made in terms of radiant energy by examining, say with a bolom- 
eter, the distribution of energy through the spectrum of the illuminant, 
and mapping the same in reference to wave length. 

That to mterpret the optical and visual values of anv such map of energy 
distribution, a series of experiments should be carriea out. once for all of 
the optical effects pertaining to one watt of radiant energy at various wave 
lengths of the spectrum, referred to the optical effect of D-wave length as 
standard. In order to obtain a fair average, this could be carried out with 
a number of different observers. Having obtained the optical value of one 
watt of energy at a suitable number of points in the visual spectrum, the 
map of energy distribution for any light tested would be capable of direct 
conversion into a numerical valuation of optical effect. 

That experiments should be made upon the effect of shape of the methven 
screen upon its light, and the influence of temperature and pressttre of the 
air upon its constancy. 

That the best form of bolometer for use in mapping energy distribution in 
spectra be studied. 

That experiments on the optical effect of one watt in the different parts 
of the spectrum as outlined be made 

That the exact determimation of the losses of reflection and absorption 
of the glass used to produce a spectrum should be studied. 

That the determination of the absorption of different varieties of lamp- 
black for long waves should be made. 

That for practical standards of light the methven screen standard, and 
special incandescent lamps at a specified voltage should be employed, their 
optical valuation having been previously determined by the radiation 
method, and from these sub-stanaards, photometric measurements could be 
made in the ordinary way. or with absorption screens. 

Also in another letter of February 8th, 1894, he states that he has suc- 
ceeded in constructing a simple and extremely delicate form of thermo-pile 
by electrically welding together a number of wires so as to form a thermo- 
junction and subsequently rolling down the junction to a few ten 
thousandths of an inch, the junctions being in series, one set being pre- 
sented to the standard of radiation and the other to the light to be 

(d.> Prof. Nichols of Cornell University, (December 4th, 1893,) hopes to 
test the following existing light standards : The Hefner, Carcel. Methven, 
Standard Candles, and the new arc standard for steadiness of light. Means 
have been found to indicate with the bolometer all the minor fluctuations 
in the brightness of such sources. 

Also with a view to producing a practical standard of light, hopes to 
experiment upon the means of securing a surface of incandescent carbon 
maintained at a constant temperature by an electric current in an atmos- 
phere of low but constant pressure of definite composition, the area of 
incandescent surface being such that direct photometric measurements can 
be made from it. The temperature of this carbon surface to be measured, 
if possible, in four ways, by chanee of length, by change of electrical 
resistance, by platinum- iridium couple, and by radiation. 

Also in another letter, Februaiy r2th, 1884, announces that he has 
obtained satisfactory life curves of various light standards by means of the 
bolometer and galvanometer. 

(e.) Professor Perrine of Leland Stanford Jr. University, (December 
23rd. 1893,) suggests specifications as worthy of being prepared for 
adoption in all standard photometrical measurements. Such, for instance, 
might refer to the dimentions of the testing room, which could be 15 ft. x 5 
ft. and 8 ft. high, lined with black flannel, and with screens of the same 
material hung from the ceiling every ten inches between the two lights 
used, which would be separately enclosed at the ends of a 100 in. scale. 

Believes that a comparative investigation should be made of photometric 
screens. A proposed screen is composed of two pieces of clear glass, 


ground together, and viewed from the edge. The position of equal 
illumination on the sides being such as will cause the line of separation 
between the glass plates to disappear. 

Also that two light standards snould be adopted of different quality for 
use with tested illuminants of corresponding spectrum distribution. Thus 
the Hefner-Alteneck standard might serve for one, and the arc-standard 
for the other, the division being made with reference to the F-line of the 
solar spectrum. 

(f .) Prof. Sheldon of the Polytechnic Institute, Brooklyn , (December loth, 


Considering that the whole subject of li^ht and illumination is intimately 
connected with the question of color distribution and relative intensity in 
different portions of the spectrum, it might be advantageous to investigate 
the constancy of the Swinburne-Thompson standard in this respect. Also 
that it would be important to investigate the change in quality of light 
emitted by incandescent carbon as dependent upon its temperature. 

(g.) Mr. Edison, (February 28th, 1894,) suggests : ** Passing slowly by 
clockwork a definite sized platinum-iridium wire through a hydrogen flame, 
surrounded by a chimney, and using a section only, of the incandescent 
wire as standard. The moving of the wire would eliminate variation in 
size and deterioration of the surface." 

I should be pleased as General Chairman of the Committee to receive any 
other suggestions or recommendations from you, or any information as 
may in your judgment be of interest to the other chairmen. 

I append a list of all the chairmen and members of the sub-committees 
as far as yet appointed. 

Very respectfully yours, 

Edwin J. Houston, 



Prof. C. F. Brackett, Chairman. Dr. E. L. Nichols, Chairman. 
Jno. W. Howell. Chas. P. Matthews, Esq. 

F. R. Upton. C. H. Sharp, Esq. 

Prof. F. B. Crocker, Chairman. Dr. F. A. C. Perrinb, Chairman. 


Herschel C. Parker, Esq. 

Prof. Charles P. Cross. Chairman. William H. Preece, Esq., Chairman^ 
Prof. William L. Puffer. Captain Abney. 

Prof. Elihu Thomson. Prof. J. A. Fleming. 

Dr. Hopkinson. 
Prof. S. P. Thompson. 

Dr. Louis Duncan, Chairman. Dr. Samuel Sheldon. Chairman. 

Hermann S. Hering, Esq. Augustus Treadwell, Jr. 

T. A. Edison. Esq., Chairman Dr. Benj. F. Thomas, Chairman. 

A. E. Kennelly, Esq. 

Prof, R. A. Fessenden, Chairman. E. G. Willyoung, Esq., Chairman. 

C. O. C. Billberg, Esq. 

E. R. Keller, Esq. 

Dr. William E. Geyer, Chairman. 


[communicated by MR. THEODOR J. W. OLAN.] 

[In discussion of Mr. Mauro's paper see p. 5A, anU.l^ 

This very interesting paper read by Mr. Mauro at the last 
meeting of this Instiiute has reference to a subject of too much 
importance to the members of this institution, and advanced too 
many startling points to allow the matter to be dropped, after 
having had no other practical result than a merely platonie dip- 
cussion. I deem it very likely that abler hands and pens than 
mine will take advantage of the invitation for a continuation in 
writing of the discussion of the subject in question. Thinking 
it proper, however, in this respect to take no chances, I 
have accepted the invitation to the end, that the Institute may 
arrive at a practical result therefrom, of benefit to the Institute 
itself, as a promoter of right and justice in legislation and proba- 
bly of benefit to most of its members, as representing a large 
portion of the inventive intellect of the nation. 

The first startling point we meet in the paper is contained in 
the following sentence on page 56 : '' It is a natural desire of 
every citizen to see the affairs of the Patent OflBce so adminis- 
tered as to produce the greatest possible benefit to the public " 
That sentence seems startling, in-so-far as it appears to acknowl- 
edge or justify the desire of the public to violate the rights 
granted to the inventor by the patent law. I have already had 
proof that the patent oflScials have seen fit to interpret their offic- 
ial duties in an analogous manner. On one occasion, when dif- 
fering with an examiner in patent matters, I was advised by him 
that I had the right to appeal from his decision. I answered 
that I would rather give up, as I did not like to come into con- 
troversy with the examiner in my first patent case. " Now," he 
said, " it is very wrong for you to have such an opinion, as, ac- 
cording to that principle, an inv^entor takes all the chances not to 
fet what he is entitled to." He laughed at his own words, and 
is assistants laughed also, apparently all conscious of the ab- 
surdity of the words expressed, and of the sophistic audacity of 
such an interpretation of the law — this by such an oflScial him- 
self, who had been put into his position in order to exercise jus- 
tice and impartiality to the best of his judgment. I took the 
examiner's words at that time merely as an improper joke without 
consequence. To-day, however, when such an interpretation of 
the patent law prevails to such an extent that its discussion is un- 
dertaken by this institution, I think the time has come for an 
earnest and decided protest against the policy outlined, and for 
a clear and conclusive demonstration of the real principle, aim 
and object of the law. In its principle, the patent law is an ac- 
knowledgment from the side of the state, of the inventor's title 
to his invention, and in consideration of a certain fee it grants 
him for a certain period the exclusive right to use for his own 
exclusive benefit, if he deems proper, the fruit of his genius. 

1894] DISCUSSION. 115 

With the exception of the fee payable to the state by the inven- 
tor, the patent law provides for no other profit for the public. 
The benefit from the patent itself during tne patent period lies 
entirely with the inventor ; and the public benefit that may be 
derived from the invention after the patent has expired can not 
have anything to do with the patent itself, nor consequently with 
the patent law or the administration thereof. 

An illustration may serve to make the evidence thereof con- 
clusive. If, for instance, an inventor had invented a flying ma- 
chine, and a patent therefor had been granted to him, said pat- 
ent would grant him exclusive right to make and use the inven- 
tion for 1 7 years. If the inventor now felt it his ambition to 
fly alone for that period, the patent law allows him that privilege 
without interference from the public. He may use it for exer- 
cise alone, or he may chase swallows, mocking birds, or wild 
turkeys ; it is none of the public's business. If the people desire 
to see the affairs of the Patent OflBce so administered as to bene- 
fit the public in other respects than as a mere source of revenue 
from patent fees, instead of the benefit of the inventor, in ac- 
knowledgment of whose right and for the benefit of whom the 
patent law was created, such desire, as abolishing the principle of 
said law, must be checked in such a way that it will not re-ap- 
pear ; and it must be checked now, since from a timid and so- 
phistic argument from the side of the patent oflScials it seems to 
liave entered into the public's mind in earnest and to such an ex- 
tent as to claim acknowledgment from the inventors themselves. 
Even the patent otiScials, — if they nre so misconstruing the law, 
and whilst exercising their ofticial duties are aiming to benefit 
the public at the expense of the inventor, for the benefit of whom 
the law exists, — must b • checked, and checked in such a way 
as to be able no longer to defy the law and violate or obviate its 

It might be said that the inventor claiming such great advan- 
tages is really asking too much. I think not. Anotner illustra- 
tion may serve to enlighten us on that subject. The state says 
to the inventor : " In consideration of a payment of $35.00, I 
sell you a suflicient piece of ground upon which to build a house. 
You must build your house yourself, and you may afterwards use 
it as you deem proper for your own bene^t and for that of your 
wife and children. 1 agree not to take it away from you until 
after a i>eriod of 17 years. I will instruct a commissioner to see 
that you touch only your own ground and to guard you during 
the erection and thereafter for 17 years, from public assaults. 
The inventi»r does not ask why the state fails to rob the prop- 
erty holder of his house after 17 years, or the farmer of his 
farm, or the banker of his cash after the same period. Although 
he knows that he has a* much right to remain the owner of the 
fruits of his labor as anybody else, he makes no objection ; he 
pays his money, ha builds his house— and after 17 years it is ta- 


ken away from him. Has the state thus granted the inTeotor 
too much ? The socialists ma^ say it has, but the adherents to 
individual ownership will say it has not, and they will appreciate 
the inventor's endeavors to defend the little right and iustice that 
has once been accorded to him. Now, since it is evident from 
the very principle of the patent law as I have tried to point out, 
that said law exists for the benefit of the inventor and not for 
that of the public, the law must be altered so as not to allow that 
principle to be subject to any assaults, either from the public or 
still less from the patent officials who have charge of the admin- 
istration of said law. it must be altered so that it will become 
impossible for those officials without serious consequences for 
themselves to place obstruction in the inventor's way under his 
endeavors to secure his right. The law must be made so clear 
and concise as to allow neither " liberality " nor " illiberality " 
from the oflScials, which will at once do away with all arbitrary 
treatment of the inventor. The law must be altered so as to be- 
come logically consequent to its different paragraphs or sections, 
so as not to give room for any interpretation leading to confu- 
sion. The law must finally be put in accord with general princi- 
ples of justice and ri^ht and in general be made so clear, conse- 
quent and concise in its form that the inventor will know that 
he has to deal with the law itself and not with the different indi- 
vidualities of various oflScials. 

The principal changes to be made, and how they are to be made 
we may largely determine from various points brought out in 
Mr. Mauro's meritorious paper. The first thing which has to be 
made clear is this. What may be subject for a patent ? The law 
answers in this respect distinctly, that subject matters for patents 
are inventions or discoveries of a certain specified nature, but the 
law does not give any definition of said expressions. 

It is evident that i^ the highest authority in patent matters, the 
Supreme Court, does not know, what, for instance, an invention 
is, since that body thinks the expression invention undefinable, 
the law itself must give a clear definition of the expression. If 
.it is a fact that the Supreme Court has denied a patent because 
the inventive faculty nad not been exercised, they have given 
proof that they can not define an invention, since they have used 
^^ defiaiendum in definituTn^'^ which is a fundamental logical 
mistake. If the expression '• invention " is clear, the expression 
'inventive" is also clear, but if the meaning of the former is ob- 
scure the latter will be the same. The conclusion must be, that 
the Supreme Court denied a patent, because something, they did 
not know what it was, had not been exercised. It is evident 
from this that the patent law as it is, does not offer the inventor 
sufScient guarantee for a treatment in the spirit of the law, not 
even in its last instance of appeal. I do not think, and I feel 
certain that this Institute will agree with me that it is not im- 
possible to give a definition of an invention, as the Supreme 
Court seems to hold. 

1894.] DISCUSSION. 117 

An invention is simply : "A solved problem, having reference 
or relation to matter." 

An invention is always caused or has its origin from a ques- 
tion put to the inventor's mind, how may this or that be done or 
made, and the invention is his materialized answer to that 

An invention in the sense of the patent law is any construction, 
composition, combination or proceeding adapted to answer for, 
or to accomplish a predetermined, useful and legal purpose. 

A patentable invention is : 

a. Any construction, composition, combination or proceeding 
adapted to answer for, or to accomplish a predetermined useful 
and legal purpose, said purpose not previously publicly known 
or perceived. 

b. Any new construction, composition, combination, or pro- 
ceeding adapted to answer for, or to accomplish a predetermined 
useful and legal purpose, said purpose previously publicly known 
or perceived. 

c. An improved construction, composition, combination or 
proceeding adapted to answer for or to accomplish a predeter- 
mined useful and legal purpose. 

Improvement, is any construction, etc., adapted to answer for a 

?;iven purpose in a cheaper, simpler, more enective or more per- 
ect manner. 

A discovery is any disclosed and previously unknown fact 
with reference to the existing. 

A patentable discovery is evidently any disclosed fact with 
reference to the existing, which can be usefully applied for a 
patentable invention. 

If we now agree, that the definitions I have given of patent- 
able inventions and patentable discoveries are suflSciently clear, 
not to allow any doubt of what is subject matter for a patent, 
according to the patent law ; the necessary amendments of said 
law in order to make it just, consequent and all through consist- 
ent with its demonstrated principle and purpose, can be easily 
concluded with a review of the different sections of the law itself. 

In section 4887 of the present patent law it is said : " No per- 
son shall be debarred, from i-eceiving a patent for his invention 
or discovery." We have there the fundamental command of 
said law, and after the clear and unmistakable meaning of that 
command, all the other sections and paragraphs of the law ought 
to be tested as to suitableness and wording in order to make the 
law just, harmonious, consequent and consistent with the prin- 
ciple of the law plainly expressed in the command. 

The first, the most important and evidently undeniable conclu- 
sion we may draw from the cited command, is that the law must 
provide sufficient guarantees for the inventor to attain his right, 
at least with the last deciding nuthority in patent matters. The 
Supreme Court of the District of Columbia is this authority. 


How has this authority proven fit for the task conferred upon it? 
According to Mr. Mauro, it does not know what an invention is, 
and it ha« declared it impossible ever to know, since its members 
have decided that the meaning of the expression invention is un- 
deiinable. And still it hajs seen fit to give decisions in patent 
cases; judging, without knowing what it was judging about. 
Does this indicate sufficient guarantees for the inventor to secure 
his rights at last? Certainly not. Without intending a slight to 
the Supreme Court, I think it impossible for a body of lawyeis 
(if lawyers simply in training and education) to exercise proper 
judgment in this matter; it lies in the very nature of things 
themselves. The thought of a mere lawyer directing a number 
of inventors reminds me of a hen put in charge of young ducks* 
Their instincts are too different for mutual satisfaction. 1 he re- 
quirement for ability regarding all the various questions that may 
arise, necessitates too fine distinctions for allowing us to hope 
fair decision from unquestionable integrity alone. Common 
sense does not constitute the only qualification for a suitable judge 
in patent matters. It is the trained skill and fine instinct derived 
therefrom which is equally necessary in the various cases. For 
illustration. Supposing a man has invented a composition of 
nitrate of potash, sulphur and carbon, which he calls powder; 
and that he had received a patent therefore, claiming broadly the 
composition of said three bodies. His composition was of a non- 
explosive nature ; when he lit it it burned, it whizzed and it 
smelled badly. Supposing now another man had invented a 
composition of the same substances in such proportions as to con- 
stitute our ordinary gunpowder. He wants a patent for his in- 
vention, but he caimot receive it because he comes in interference 
with the first inventor refered to. A Supreme Court judge will 
probably in this case decide that, as there is no need of exercising 
the "inventive faculty" for putting a little more or less of each 
of three known substances into a composition, the patent cannot 
be granted ; a man skilled in the art would decide that, as the 
proportion between the substances in question in this case was 
just as essential as the substances tht^mselves, a patent to the latter 
inventor must also be granted. I am sure this Institute is of 
the same opinion. Whikt the first inventor ought to retain his 
patent right, so as to enable him to rest peacefully in the evening 
by ths use of his compound to drive mosquitoes out from his i oom 
in summer-time, the second inventor ought aUo to have his patent 
granted in order to allow him to work our mines, open our tun- 
nels and help the kings, the emperors and the presidents to make 
war against each other and amuse themselves. Many similar 
illustrations could be given for tlie delicAcy of the task conferred 
upon the last deciding authority in patent matters, and circum- 
stances point direct to the following conclusion : The last deciding 
authority in patent matters must be a jury of men. skilled in the 
appertaining art in each case, selected from among men outside the 

1894. 1 DISCUSSION. 1 19 

patent office by the contesting parties themselves. This would 

five the inventor, if not absolute certainty, a fair chance to get 
is right in the last instance. 

It is, however, not enough that the inventor should be able to 
secure his right in the last instance. The law says he shall not 
be debarred from obtaining it, which apparently means that 
no obstruction or delay should be put in his way, since he has made 
his application for a patent. What provisions are made in the 
following sections of the law for giving effect to the command 
and what is the inventor's practical experience with reference 
thereto ? 

Section 4888 directs that the inventor, to receive a patent, 
shall make an application in writing describing his invention in 
such full, clear, concise and exact terms as to enable any person 
skilled in the appertaining art thoroughly to understand the nature 
and use of the invention. 

This requirement complied with, the law provides that the 
Commissioner shall cause the examination of the alleged new in- 
vention or discovery. On whom is this task now conferred ? 
On the principal examiner and his assistants. The principal ex- 
aminer — who is he, according to law ? Nothing is provided for 
his qualification by law. We may, however, take for granted 
that he must be able to read and write, that is all. Thus the 
specification legally composed for a man skilled in the art, is to 
be judged by a man who may have common school training and 
who may not. The inventor, although having conaplied with 
the law as to specific completeness and clearness of his specifica- 
tion, is subjected to innumerable objections due to inferior 
ability It is not at once clear how two times two make four ; it 
has to be shown how four plus three gives seven, etc., may be 
taken as standards for the objections very often raised. To sat- 
isfy the examiner the inventor will have to try and make those 
obscure points dear ; he will have to compose as many finished 
lectures suitable for a priniary school, as letters with reference to 
objections made. When he has at last succeeded in finishing one 
objection, another one is raised; and when this is done with — yet 
another. He will have to spend money for legal assistance often 
many times more than the entire patent fee. He will have to 
sacrifice his time, armor his patience, dominate his temper, and 
be up early in the morning. 

If he at last succeeds in suiting the examiner and gets his pat- 
ent allowed he may regard himself fortunate. In many, perhaps 
most cases, he has to appeal to the examiner-in-chief; and now 
at last he has come into the hands of an authority legally quali- 
fied to understand his description, perhaps. The examiner-in- 
chief must, according to law, be of scientific ability, and there 
are great chahces then that he will understand a specification 
written for a man skilled in a certain art. The legal number of 
examiners-in-chief are three, and there are therefore threefold 


chances for the inventor that one of them may have some ability 
in the respective art to which his invention belongs. If the in- 
ventor now gets his right from the examiner-in-ehief , he is again 
fortunate; but if he does not get it, he can again appeal. To 
whom ? To the Commissioner. The Commissioner, who is he ? 
The law says nothing of his quahiicatione, but from circum- 
stances we may conclude that he is either a republican, or a dem- 
ocrat, or a mugwump, that is all. The inventor, unable to judge 
from that as to the skill and training in the arts possessed by 
said gentleman, has to shut his eyes as to the possibilities of his 
chances and blindly cast his twenty dollar pieces in the air. 
Perhaps he will hit a sparrow, perhaps not. If, however, the 
Commissioner acknowledges his rights and grants his patent he 
is fortunate. At all events his case is finished as far a« tne Patent 
Office directly is concerned. Now, supposing the inventor was 
accorded hie right at last by the Commissioner, is he to be in- 
demnified for all delay caused by obstructive and uncalled for 
objections and for his loss of time and money in his endeavors to 
secure his right? Is the principal examiner to reimburse him 
the appeal money — paid on account of his wrong decision, or the 
examiner-in chief for the increased expenditures caused by his? 
Certainly not ; his case is closed, and the examiners are left un- 
disturbed to continue the same course with reference to other 

The more obstruction there is raised in the inventor's way, the 
more wrong decisions to be appealed from, the more money the 
Patent Office will make ; and when the year is at an eud, the 
office will in this way have paid in a surplus to the Treasury of 
one million or two, no matter if most of said surplus is ill earned 
pelf. Is this state of things a desirable one '( Is the praxis here 
referred to consistent with the clear fundamental command of the 
law, that no man shall be debarred from receiving a patent for 
his invention or discovery. The sections of the law not prevent- 
ing such obstruction but rather favoring it, are they consequent 
with cited fundamental command ; are they based upon the in- 
variable principles of justice and right, which ought to be the 
desirable aim for all legislatures. Decidedly not. I do not mean 
to say, that, as long as the law provides for an examination of 
applications for patents, there should be no objections raised ; 
but what is undeniable is this, that the inventor should not be 
obliged to fight with the patent officials for " what he is entitled 
to ". It should be clear not only from the fundamental command 
of the law, but also from all the subsequent sections thereof, that 
the patent officials have been placed in office not in order to try 
to defeat the inventor under his endeavors to come to his right, 
but to benevolently assist him under his endeavors. The law 
should therefore be altered so as to clearly point out this as the 
always directing rule for the various duties of said patent officials, 
and provision should be made to enforce said rule, if they after- 

1894.] DISCUSSION. 121 

wards failed to see, or failed to fulfill their duties. The law 
shoald be altered, so as to do away with all undue obstruction 
not only due to inability, but also that heretofore experienced 
from over zealousness of misunderstood duties, or from a desire 
to benefit the Patent Office financially, in excess of what is 
required by law. It needs no demonstration to prove, that the 
present provisions in appeal cases ma^ be construed as a direct 
invitation to the patent officials to raise in the inventor's way as 
many adverse decisions as possible in order to cause as manv 
appeal fees as possible to be paid. Nobody argues, that aa- 
verse decisions shoald not be made if they are just and qualified, 
and that on the other hand some inventors may appeal from an 
adverse but correct decision ; but that the inventor shall pay the 
appeal fee whether he is right or wrong ; there is where the in- 
justice comes in. 

The provisions in reference to appeals should therefore be 
altered not only on account of the misuses to which they clearly 
may lead, but also in order to accord with principles of justice 
and right. 

I think we are able here to make the following conclusions : 

First : The patent law should make provisions for necessary 
qualifications of all the patent officials so as to provide guarantees for 
their necessary ability to fulfill the duties conferred upon them, 
so far as possible without error or mistakes. 

Second : The examiners of patents should be well paid so as to 
enable them to direct their entire attention to their duties, as they 
should be of adequate number for carrying on the business of 
their office without overwork or strain, and the work required 
from them should be so limited, as to enable them to follow the 
progress in the art, and to make themselves more and more fit 
for their duties. 

Third : The patent officials should be made independent of 
political influences whereby able men who have either already 
•entered in service or who may in the future be appointed could 
be retained in office. 

Fourth: For evidently misconstruing the provisions of the law 
for making arbitrary decisions in defiance oi said law the officials 
should be removed from office. 

Fifth : An official record should be kept, with reference to decis- 
ions of each separate examiner, subsequently reversed upon appeal; 
and no examiner should be allowed to retain office, after having 
had a limited number of his decisions reversed. The inventor 
should be reimbursed by the losing examiner for all expenditures 
for appeal fees, in cases ultimately decided in his favor. 

Sixtn: No authority in the Patent Office should have any ad- 
judging power in appeal cases, if he is not by scientific merit and 
skill in the arts, fully qualified for such duty in the strictest sense 
and spirit of the law. 

That the last and highest authority in patent appeal cases should 

122 MA URO ON Til hi PA TENT OFFICE. \ Mar. 21 ^ 

be a jury composed of men of scientific ability and skill in apper- 
taining matters as we have already concluded. 

When the patent law has been so altered as to contain provisions 
embodying the changes htre above suggested, and deduced as 
necesFary conclusions from the discussions of the matter, then I 
think the law will become harmonious and consonant with refer- 
ence to its fundamental command, principle and aim. 

1 think if this Institute took the initiative in promoting the 
necessary changes in the patent law referred to, it would not only 
highly favor its own interest and authority, but also benefit a 
great number of its members and earn the gratitude of the in- 
ventors of the nation. The latter have long enough spent their 
time and money in fiitile efforts to get the benefit of rights, 
granted to tiiem and acknowledged by law, but not accorded to 
them by the administi ators of said law. 


New York, March 21 et, 1894. 

The eighty-fifth meeting of the Institute was held this date 
at 12 West Slst Street, and was called to order by President 
Houston, at 8 P. M. 

The Secretary read the minutes of the last meeting, which, on 
motion, were approved. 

The S^retaiy read a list of associate members elected, and 
transferred to full membership at the Council meeting March 
2l6t as follows : 




Endorsed by. 
W. B. Vansizc. 
C. F. Brackett 
G. A. Hamilton. 
Carl Hering. 

Electrical Engineer, Kinsman Block 
System Co.. 23 West 39th St., 
New York City. 

Electrical Engineer, Thomas H. 

Dallett & Co . 3200 Arch St., E. G. Willyoung. 
Philadelphia. Pa. Fdwin J. Houston. 

Bliss, William L., S, 5., M. M, E, Electrical Engineer. Andrew L. Riker 
Rikcr Elcctnc Motor Co., 24 James Hamblet 
Irving Place. Brooklyn. N. Y. 

Electrical Engineer. Sprague Elec- 
tric Elevator Co., 126 West 34th 
St.. New York City. 

Engineer, Waddell-Entz Co.. 

203 Broadway, New York City 

Carichoff. E. R. 
COHO, Herbkrt B. 
Galletly, J. Fred. 
Jackson. Henry 

Keller. Edwin R. 
Kirkland. John W. 

T. C. Martin. 

Henry W. Fiye. 

W. D Weaver. 

E C. Davidson. 

T. C. Martin. 

F. J. Sprague. 

C. T. Hutchinson. 


Swift & Co., 

Chicago. 111. 

Telegraph Supt. and Engineer. The 

Lancashire & Yorkshire Railway 

Co., Horwich, Bolton-le-Moors, 

Lancashiie, England. 

4823 Springfield Ave., 

Philadelphia. Pa. 

Electrical Engineer, 

General Electric Co., 

Schenectady, N. Y. 

Clark C. Haskins. 

George Cutler. 

Fred. DeLand. 

Ralph W. Pope. 

T. C. Martin. 

Joseph Wetzler. 

E. G. Willyoung. 

Carl Hering. 

Edwin J. Houston. 

Jas. B. Cahoon. 

C. P. Steinmetz. 

H. G. Reist. 


Phillips, Leo A. Westing^house Electric and Mfg. Co., Philip A. Lange. 

98 Green St., Nikola Tesla. 

Newark, N. J. L. A. Osborne. 

RouQUEiTE, Willi A.M F. B. Proprietor, Rouquette & Co., Charles Hewitt. 

I a Wooster St., James Burke. 

New York City. Geo. R. Metcalfe. 

Rowland, Henry A. Professor of Phys'cs, Frank J. Sprague. 

Johns Hopkins University, Louis Duncan. 

Baltimore, Md. C. T. Hutchinson. 

Smith, J. Brodie Supt. and Electrician. Manchester Geo. F. Curtiss. 

Electric Light Co., 742 Merri- Sidney B Paine. 

mack St., Manchester, N. H. Caryl D. Haskins. 

VoiT, Dr. Ernst Professor of Electricity, Technical Benj. F. Thomas. 

University, Schwanthalerstrasse, C P. Steinmetz. 

Munchen, Germany. F. W. Tischendoerfer. 

Total 14. 


Approved by Board of Examiners, December 7th, 1893. 

Almon, Geo. H. Supt. Construction New England District, General 

Electric Co., Boston, Mass. 
Egger, Ernst Electrical Engineer, Vienna, Austria. 

Brenner, \V. H. Electrical Engineer, Montreal Street Railway Co., 

Montreal, P. Q. 
Haskins, Clark C. City Electric Light Inspector, Chicago, III. 

FiTZMAURiCE, James S. Chief Engineer Electric Light Branch, Sydney, N. 

S. W. 
Total 5. 

The President : — Mr. Kennelly notified the Institute at the 
last meeting that he would move to take from the table the re- 

Eort of the Committee on Units and Standards. Mr. Kennelly 
as the floor. 
Mr. Hamilton : — I would like to move that the report be 
taken up for reconsideration now. 

[The motion was carried. The report is as follows :] 


New York, Nov. 15th, 1893. 
To the President and Council, of the 

American Institute of Electrical Engineers, 

Gentlemen : — Your committee on ** Units and Standards " begs to 
recommend to the Institute the provisional adoption of : — 

The term "gilbert" for the c. g. s. unit of magnetomotive force, the 
same being produced by 0.7958 ampere-turn approximately. 

The term *' weber*' for the c. (;. s. magnetic unit of flux, sometimes 
described as the c. g. s. line of flux. 

The term '* oersted " for the c. g. s. unit of reluctance. 

The term *' gauss " for the c. g. s unit of flux density, or one weber per 
normal square centimetre. 

The committee, it will be remembered, in its previous report, dated 
June 20th, 1 891, advocated that the above terms should be accorded to 
magnitudes in conformity with the ••practical" electromagnetic system, 
and therefore following in natural order and extension from the volt, ohm, 
ampere, and other units in universal use. 


As, however, so important a series of new unit magnitudes could only 
meet with general recognition and favor under the authorization of an 
International Electrical Congress, which authorization has been withheld at 
the recent Congress at Chicago and since objections have been raised to 
those magnitudes, your committee considers that the urgent need for 
names specifying the principal quantities dealt with in magnetic circuits 
can best be met with general favor, by adopting for those names the 
fundamental unit magnitudes of the international c. g. s. system after the 
precedents already estabhshed in the cases of tjhe c. g. s. units of force and 
work, entitled respectively the *' dyne " and ** erg." 

Yours very respectfully, 
Committee on Units and Standards 

F. B. Crocker, 
W. E. Geyer, 

G. A. Hamilton, 

A. E. Kennelly, Chairman, 

The Pbesibent : — Does Mr. Kennelly wish to open the dis- 
cussion il 

Mr. Kennelly : — I think, sir, that on the occasion of the meet- 
ing before last, the vote by which that report of the committee 
was laid on the table, was a vote given by some of the members 
under a misconception. I think you will remember, sir, that 
there were two motions before the Chair, and that some of the 
members informally stated that they had voted upon the second 
motion believing it to be the first, and in case the intention of 
the meeting were taken again it might be found that a majority 
of the meeting were in favor of the adoption of the report. 

Mr. Townsend Wolcott:— Mr. Kennelly's remarks on this 
subject are printed in the March issue which we have to-night. 

In regard to the adoption of the names of electricians for 
these c. g. s. values, Mr. Steinmetz objected to that on the ground 
that it was not according to the other c. g. s units, and I do not. 
think that anybody outside of this country would approve of 
that point. I objected myself on the same ground, but that has 
nothing to do with what 1 now say. I do not think that foreign 
electricians would approve of it. If vou could get names like 
erg and dyne, I should be strongly in favor of them myself, but 
I do not think it is a fact that if we fall to adopt names for 
those quantities, there will be any great difficulty experienced. 
Mr. Kennelly's argument here is that 300 grammes is very much 
more definite than 300 units of weight in flie o. g. s. system. Of 
course, that is a very cumbersome expression if it were necessary 
to use it. But we have in common practice expressions some- 
what of that nature. We have several kinds of units which are 
called by the name of degree Degree does not mean much 
more than the word unit. There are two or three different kinds 
of degree. In the first place, the quadrant is divided ordinarily 
into 90 degrees, and by the French it is divided into 100 degrees. 
I do not think it would make it any more plain what these words^ 


were, or would give any more of a concrete idea of the things 
themselves, if you called them Le Verriers after the astronomer 
who did the work. In the ordinary thermometer scale we say 
the temperature is so much. For instance, we say, it is very 
warm to-day ; it is 90. We mean to say 90 degrees. Every- 
body knows what you mean if you just say 90. If there was 
any doubt about it you would have to say 90 degrees on the 
Fahrenheit scale, because we use Fahrenheit in this country. 
When we come to magnetic units, if there is a name attached to 
a unit, unless it be a very short one and very convenient to use, 
it would not be used at all by a great many people. I, myself, 
always speak in this way of tne density, if I am talking to a man 
who knows what I mean by the density of magnetic induction. 
You just say it is a density of 16,000. You do not say it is a 
density of 16,000 c. g. s. lines per square centimetre. That is 
entirely unnecessary. I wish it understood that I do not disap- 
prove of naming those units at all, if you can get some good 
names. But I do not think that science is going to suffer so very 
much if we do not name them immediately. 

Another thing is, the provisional adoption of a name is worse 
than no adoption at all, I think. We already adopted one name 
provisionally The foreign electricians adopted the name 
*^ weber ' for unit of current, and then changed it to '• ampere." 
Some books have " weber " in them still. If you adopt a nam© 
and then change it afterwards, it makes it worse than if you 
never adopted it. We have heretofore made mistakes by being 
in too much of a hurry. If they had not been in too much of a 
hurry to get a new value for the ohm, there would be only two 
values for the ohm in use. At present there are three — the 
British Association, the legal ohm, and the international ohm. 
So it would be with names, if you adopt any names provision- 

Some one says — 1 do not know whether officially or not — ^that 
if any one would find good Greek names that would do, the com- 
mittee would adopt them, but we have not got the Greek names. 
It seems to me that we ought to have some Greek scholars. Mr. 
Kennelly says we do not possess the facility for creating Greek 
names in this country that would meet general apprehension and 
support. Well, although that may be so, I do not know why we 
should not be able to make Greek names in this country as well 
as in England. 

Mr. Kennelly : — I think that the point that Mr. Wolcott 
mentions is the very one that 1 would have selected on the other 
side if you would give me a moment's hearing. When you say 
16,000 you do not at the present time know what that means. It 
may mean 16,000 lines per square inch or it may mean 16,000 per 
square centimetre, and for that reason there is an argument in 
defining what it means by saying 16,000 gausses. 

Pbof. Fbanois B. Crocker :— If you are thoroughly familiar 

1894.1 DISCUSSION. 127 

with the Biihiect and expect a person to make a certain remark, 
why then, of course, you can understand it. But assume that 
vou are teaching some one who knows absolutely nothing about 
it. I have had some experience in that direction, and I find that 
until I can attach a concrete name to a unit it is rarely ever com- 
prehended and it certainly takes a great deal longer to make it 
understood. That nmst be evident to any one who has made 
any attempt in that line. Mr. Wolcott probably referred to con- 
versation between two electrical engineers both of whom are per- 
fectly familiar with the subject, each knowing about what the 
other is going to say. But in speaking to some one who is 
learning, I think you will find that the absence of a concrete 
name will do more to give an indefinite idea than any other one 
thing, and the presence of a concrete name would do a great deal 
towards giving a definite idea. In fact I deny that a general 
name like '* c. g. s. unit of magnetic fiux," or even *' unit of 
flux " will ever be clearly understood by any but technically edu- 
cated persons. Now we all know that common workmen can 
use the terms "volts," and "amperes" and "ohms" just as 
intelligently, and for their purposes just as accurately and just as 
satisfactorily as the most learned electrician. I do not think that 
woul<i be possible, in fact I am quite sure it would be utterly 
impossible if we called them "al)Solute units of electromotive 
force," or even " units of electromotive force," because such men 
are not accustomed to abstract ideas. They can measure electric 

(pressure in volts and they understand exactly what it means— at 
east well enough for their purposes and for the purposes of the 
persons who employ them, but if they had to resort to abstract 
terms they could not apply them intelligently This is true also 
of persons beginning the study of electricity even though they 
are educated, and in both of these cases I say the giving of defi- 
nite names would be of enormous assistance. Now in the case 
of men who are thoroughly familiar with electrical and mag- 
netic science and who know exactly what they are talking 
about, I admit that the necessity is not so great ; but even then, 
unless the context or the circumstances indicate exactly what is 
meant, there is apt to be the ambiguity to which Mr. Keimelly 
referred, that we unfortunately use both ceni metres and incht s 
in this country and in England, and we use them about equally 
often, and I should be at a loss to know when any one said 
*' 10,000 lines" whether he meant per square inch or per square 

I think that electrical science owes a great deal of its exactness 
and its progress, and its extremely perfect condition at the pres- 
ent day, to the fact that we have definite units with dennite 
names, and no other science approximates electricity in that re- 
spect—even mechanics which is much older and is supposed to 
be more exact than electrical science. But mechanical science 
at the present moment is much less definite, and there is much 


more uncertainty even in the use of such words as " power " and 
"work" and *' force" than there is in the use of electrical unite. 
I attribute, as I say, the definiteness of electrical science to the 
very satisfactory condition of electrical measurements and ter- 
minology. I attribute it largely to the fact that we have definite 
names for definite things and we do not call them units of some- 
thing or •* degrees," or other indefinite terms that mean nothing. 

Mr. Wolcott : — I would say that, perhaps, I did not make 
myself clear enough in what I said before. The examples I took 
were things that are used by uneducated people as well as edu- 
cated people. Take the mariner's compass. Certainly ordinary 
seamen are not better educated than the students who begin to 
study electricity, and they know what a point on the compass is. 
Knowing it by the name point, it means just as much for in- 
stance, as if they called it a Marco Polo, because Marco Polo 
had something to do with introducing the compass into Europe. 
On the same line of reasoning, I say one line of force means 
just as much as though you called it by some man's name. As 
to what Professor Crocker said in addition to that, that people 
do not get mixed up when they have definite names to deal with, 
we certainly have a definite name in " watt." Watt is supposed 
to mean something very definite, and yet a great many people,, 
including college professors, talk about " watts per minute " and 
" watts per second." That is a mistake that is made very often. 
I think it occurs just about as often as if you did not have the 
name "watt." They mix up "watts" and "joules." 

Mb. C. S. Bradley : — This subject seems to have been sub- 
mitted to a well chosen committee. I think there is none of us 
who could spend the time they have spent on it, and if the thing^ 
is to be adopted in any shape, manner, or form, it would be well 
to take it as the committee have submitted it, with one excep- 
tion. I think the whole turning point is on the question whether 
this body wants to assume the responsibility of deciding this 
question alone. I would suggest that it be submitted to at least 
two of the foreign bodies of electrical engineers — the English 
and the French. It will make some delay, but it would seem to 
be a good policy, and I would, therefore, make the motion that 
we submit this question to the foreign bodies and await an 

Dr. Wm. E. Geyeb : —I understand it is not proposed that 
we adopt this unit once for all, and dictate to the world to 
accept it. It is only a provisional adoption, with a view, if pos- 
sible, to inducing other bodies to follow us. I think we did 
something similar in the case of the henry, and succeeded 
very well. We did not attempt to lay down the law to the rest 
of the world. We simply suggested it, and by doing a similar 
thing in this case we may also succeed. 

Mr. Bradley : — I think it is far more dignified to submit the 
(question prior to any adoption, although it may take a little more 

1894.] DiaCU88I0N. 129 

The Pbesidbnt : — Will you pardon your President for speak- 
ing a moment on the subject ? I quite agree with what Prof. 
Crocker has said respecting the advisability of having definite 
names for definite ideas, especially when you wish to convey 
those ideas to others. As a teacher, I find it almost an absolute 
necessity if I wish to convey an idea, to clothe that idea in the 
briefest language possible. I know the dangers that arise from 
contrasting thinss that do not exactly resemble one another, but 
any of you who nave endeavored to give to a class of young men 
ideas of magnetic flux, desiring to show the relation existing 
between the magneto-motive force and the reluctance, and to 
draw comparisons between the ideas of electric flux or current 
and to show the similar relation between the electromotive force 
and the resistance, will, I feel sure, find great advantage in hav- 
ing names adopted for the units of magnetic flux, magnetomotive 
force, and reluctance. Of course it does not express any more, 
when you say there is a similarity between the amperes, between 
the volts divided by the ohm, and the webers and the gilberts 
divided by the resistance, but still it does help very greatly to 
give the ideas. 

I do not at all agree with the member who thinks it is neces- 
sary or even advisable to submit our action to any foreign bodies. 
It is only an action which, if we are ready to teke, we simply 
announce to the world that pending the adoption of better names, 
we propose to use the terms " gauss," " weber," "gilbert," and 
" oersted." It does not seem to me that the argument of Mr. 
Wolcott is really deserving of very ^reat consideration — namely 
that heretofore we have adopted for the names of units, the 
names of electricians who have passed from their labors, only m 
the case of the practical unit. If they have served well in the 
place of the practical units I see no reason why they should not 
also serve in the place of the o. g. s. units. It seems to me, 
therefore, that the JNSTiTcrrE would be quite warranted in taking 
this step, which is recommended, after aue consideration, by cer- 
tainly a very able committee appointed by you. 

Mb. Bradley : — I think it is a courtesy to the foreign bodies, 
and I think all those things will draw us all into sympathy with 
them We are all living in a world, and the more nearly we are 
working together the more we are in sympathy, and it seems to 
me a good opportunity to oflfer courtesy. 

Db. Caby r. Hutchinson : — It would seem that the advis- 
ability of doing what is proposed, mi^ht depend to some extent 
up on whether you can get other people to follow your example. 
Were not all these names suggested to the Chicago Congress, and 
did not it decline to act on them ? It seems rather absurd to 
attempt to adopt a lot of names which others will not use. 

The Pbbsident : — I do not think these names were actually 
acted on. 

Db. Hutchinson : — I think they declined to take any action on 


Prof. Crockeb :— That same argument was used against the 
henry, and in that case the result was extremely satisfaetorv ; 
80 satisfactory that a Frenchman moved the adoption of tLe 
name, and an Englishman seconded it. It was not even neces- 
sary for the Americans to urge it. Now, in this case we can 
simply do exactly as we did in that previous case. We suggest 
something to the electrical profession of the world, which we 
think desirable. If they see iit to use it, as they did in the case 
of the henry, then the next international congress will, pro- 
bably, adopt it officially. Furthermore, all those who took part 
in the Chicago Congress were unanimously of the opinion that 
the real work of introducing a new unit or term has got to be 
done hefore a congress meets. The unit has got to be adopted, 
unofficially, by electricians throughout the world before it can be 
adopted officially by the congress. A congress has no time to 
discuss the merits of introducing a unit. It is simply a question 
of whether they will accept it or not, and they barely have time 
to decide even that Question. So it was, I think, the opinion of 
<»very one at the Cnicago Congress, that the real material on 
which a congress can work must be provided for it, and that the 
suggestions must all be threshed out before the congress meets, 
and a long time before, if possible. 

Dr. Hutchinson : — My point is simply that these names have 
been before the Congress. Prof. Crocker is right in saying that 
they should be adopted by the entire electrical community of the 
world, and since the representatives of other countries in common 
with those of this country have declined to take action on this 
matter it seems rather like trying to force things down their 

Mb. a. E Khnnelly: — I think it is only fair to say that these 
names came before the Chamber of Delegates at the Chicago 
•Congress, not for these magnitudes but in connection with a sys- 
tem of practical units, so called, so that the fact that they were 
not endorsed by Congress need not be construed to their disadvan- 
tage in this presentation. It is out of our province, of course, as 
a practical body of this kind to create fundamental scientific mag- 
nitudes. But here are units already in existence. Here are 
things that we use in our every day work needing names. It 
surely is within our province to give those provisional names. 

Dr. M. I. PupiN : — Mr. President, as Mr. Kennelly remarked, 
the units have already been fixed. They are bom ; all they need 
is to be christened. Now, the question is, who is to be the god- 
father. That seems to be the whole diflSculty. The Germans 
would probably not care to stand godfather to anything that does 
not bear a German name. The English probably feel about the 
same way, the French the same. We know what difficulties they 
had at the first Paris Congress. The difficulties arose, not so 
much in connection with the magnitude of the units, as in con- 
nection with the names to be applied to these magnitudes. There 

18M,] DISCUSSION. 181 

seems to exist considerable international jealousy, naturally so, 
on the other side. There is no international jealousy on this side, 
because we are all one. It is probably owing to this circum- 
stance that there is so much less of mental inertia, on our side, 
when it comes to naming units. We do not hesitate to give some 
name to a unit if we think that such and such a name deserves 
the honor. Now, I do not think that there is much doubt about 
the names *' gauss," ^^weber," "gilbert," "oersted," etc., as 
being appropriate to the units to which our committee on units 
assigned the distinguished honor. The question is this — who is 
to propose these names for the units ? I think that we here, in 
the American Institute op Electrical Engineebs, occupying 
as we do a neutral ground, are really called upon to make that 
proposition, and our friends on the other side, upon caref nl con- 
sideration, will find that we, standing on neutral ground, could 
see with a much clearer view, with much less prejudice, that the 
names just lit the things to which we have applied them. I 
think that the suggestion of Mr. Bradley, if carried out, will 
cause considerable delay. It is not necessarv for us to wait for 
the other engineering societies to express their sentiments in the 
matter. Let us propose the names and let them act in any way 
that they may please. 

Dr. Geyer : — Of those names proposed, two, " gauss " and 
*• weber " are the names of men so pre-eminently great, that if 
proposed by what might be called a neutral, as we in America, 
are, I think the rest of the world will really be ready to lay aside 
its jealousies, and even if that were not quite the case, these 
men were so great in their line that it seems to me a matter of 
common justice that they should be somehow commemorated. 
We are all very grateful to the British Association for getting 
out a physical unit called the ohm, and we all appreciate the 
work thev did in giving us the name of " volt " and " farad." 
But the British Association merely adopted the work of Gauss 
and Weber, simply modifying the magnitude of some of the 
units. But the system was really that of Gauss and Weber, and 
I have very h'ttle doubt that if, in those times, magnetic units 
had been of as much importance as they are now. Gauss would 
have immediately received some recognition, had the measure- 
ments of the current played any great role in those days. Then 
it was essentially resistance and capacity and electromotive force 
that were important in the electrical measurements. Currents 
were not used of any appreciable magnitude, except, perhaps, in 
electroplating, and that is more or less an occult art. I mean to 
say, that if current had been used in those days in any consider- 
able magnitude, and Weber had not been at that time living* I 
should venture to say that he would at once have received rec- 
ognition. 1 do not mean at all to disparage the labors of Am- 
pere, but I should say that he was, at least, the equal of Ampere. 
Now, the name for the unit of current is adopted. You cannot 


change that. But we might do the next best thing, it seems to 
me, and give one of these great men, at least, a recognition in 
something that is analogous. The objection has been made that 
the name " weber " is unavailable because it has been used in 
another connection. But that other connection is so different, 
that no one knowing the simplest element of electricity and mag- 
netism would ever run the least chance of confusion. 

Mr. F. S. Holmes : — At the meeting before the last, when 
this question was brought up to be acted upon, there were two 
questions in my mind that led me to hesitate ; the first, as to the 
magnitude of the units, and the second, as to the permanence of 
the names which we might apply to them. We certainly do not 
wish to apply the names of several scientists to certain units for 
an indefinite period ; for, it may be, one, ten, or fifteen years, 
and then have the name entirely changed, or the magnitude of 
the unit altered, and, therefore, a confusion arise at that time. I 
think we all of us are in hearty sympathy with this committee 
in their effort to objectify, to bound, to term these units, so that 
they have a substance that we can describe and impart to others 
in short order. But I am very glad to say that the discussion, as 
it has gone on to-night, has led me to believe that possibly we in 
America may help to roll on this cause by applying these names 
tentatively, and may overcome some foreign jealousies and diffi- 
culties that would lead scientists abroad to object to having nearer 
neighbors name the units. 

Dr. Hutchinson: — The point is just that — ^applying names 
tentatively when you do not know that they will be adopted, and 
the possibility of others applying other names tentatively, which 
would lead to confusion. 

Mr. Kbnnblly : — Since somebody has to make a start in ob- 
taining names either in this country, or in England or in Ger- 
many or France, and since various inchoate attempts have been 
made, as evidenced in the technical journals from time to time, to 
create names, I beg to move that the names be adopted provision- 
ally by the iNsirruxic at this time. 


The President : — It is moved and seconded, as you have 
heard, that these names mentioned in the report of the dommittee 
on Units and Standards be adopted provisionally by the Institdte. 

[The motion was carried.] 

The President : — I take pleasure in introducing to you Prof. 
William A. Anthony, who will read a paper on the Effect of 
Heavy Gases in the Chamber of an Incandescent Lamp. 

Prof. Anthony read the following paper. 

A >tf>#r ^t9€nted at the Bighiy-fifth Mttting of 
the American Institute of Electrical Engin- 
eers^ AVw Yorky President Houston in the 
Chair: and Chicago, Manager Hibbard in the 
Chair. Mareh 2ist^ i9g4. 



Since the issae of Edison's incandescent lamp patent in 1880, 
it has been the generally accepted theory that the principal 
cause of the decay of the filament of an incandescent lamp 
other than oxidation, was the mechanical action of the small 
amoant of gas remaining in the chamber, wearing away the fila- 
ment by the attrition due to the air currents, or as Edison called 
it " air washing." Electrical forces are also supposed to have 
some effect, carrying the carbon from the filament to the walls of 
the chamber. The perfection of the electric lamp upon this 
view was to be sought in the direction of a higher vacuum, and 
more firm and solid carbons with a smoother surface. Improve- 
ments in carbons have done much to improve the lamp. As car- 
bons are now made — built up by deposit from a hydro-carbon 
vapor — every interstice is tilled, and the surface becomes almost 
as smooth as, and has almost the appearance of, polished steel. 
Such a carbon withstands well the " air-washing " effect of the 
jresidual gases, and the life of the lamp at a given temperature 
is greatly increased. But as it is greater economy, up to a cer- 
tain point, to increase the temperature and save energy, than to 
keep the temperature down and save lamps, temperatures have 
been increased as carbons have been improved, and efficiencies 
have been raised until, in new lamps at least, a candle power is 
obtained from less than three watts, instead of four or more. 
But with these higher efficiencies comes a new cause of deterior- 
ation not so apparent in the low temperature lamps, the black- 
ening of the bulb and consequent loss of transparency and de- 


cline in candle power. When I see incandescent lamps hung 
for use, I involuntarily find myself looking for blackened 
lamps, and it is no uncommon thing to see those through 
which objects look dim. Sometimes I see lamps so black that 
they would do for smoked glass in viewing an eclipse of the 
sun. I have taken down such lamps and measured their 
candle power and eflSciency. Very often they run as low as ten 
candles and six or seven watts per candle at their normal volt- 
age, and I have found lamps below six candles and ten watts per 
candle. The customer was still using these and had not "kicked" 
so far as I know, though he was sure he was not getting the 
light he did at the beginning. Generally he does not know what 
the matter is, thinks, perhaps, the company is parsimonious with 
the "electricity," but hasn't said much, "because he doesn't 
want to be all the time making a row." Of course, the illumi- 
nating company cannot be expected to go around and hunt up 
such lamps and change them; so, as long as the customer does 
not complain, but pays for his six or ten candles at the price of 
sixteen, the old blackened lamps remain on the circuit until they 
bum out. Since such lamps increase in resistance they take less 
and less current, and the older and more feeble they become, 
the more tenacious they are of life. It is no uncommon thing 
to hear of such lamps that have lived through six, eight, or ten 
thousand hours of active service, when, probably, not one of 
them was able to do its full duty, and should have been placed 
on the retired list, at three hundred hours. 

Now the question arises, is there no way to preserve the illu- 
minating power of the lamp throughout the life of the filament ! 
Surely a long-lived filament is of little value if it fails to give a 
reasonable light after two or three hundred hours. 

Loss of candle power might be avoided by lowering the tem- 
perature and with it the initial efiiciency of the lamp, but this is 
an improvement in the wrong direction, although I am sure the 
customers, whether they pay for their electric energy by the meter 
or by the year per lamp, would be the gainers if they were fur- 
nished with lamps of lower initial eflSciency, unless their lamps 
are changed oftener than is usually done. The present high 
eflSciency lamp would do very well if there were any way to in- 
sure its retirement from the service when its legitimate useful- 
ness was passed. The ide<il lamp would be one that, while 
giving a high efiiciency and a reasonable life, should die by the 
rupture of its filament while still doing its best work. 




About a year ago Mr. John Waring began experimenting upon 
the eflfects of heavy gases in the lamp chamber, using principally 
the vapor of bromine as obtained from the liquid bromine of 
commerce. It is not necessary to describe in detail the various 
experiments. The final result reached was that, when bromine 
vapor was present in the chamber in proper quantity, the lamp, 
as compared with a vacuum lamp, could be run at a higher effi- 
ciency without blackening or increase of resistance, therefore 
without loss of candle power and with an increase in its ireful 
life. These facts were abundantly demonstrated by numerous 
experiments. Below are the results of some experiments that I 
myself recently performed. I had made a number of 50-volt 16- 
candle lamps. Half of these were exhausted in the usual way as 
vacuum lamps. The others were made into bromine lamps after 
the method employed in the Waring factory. The lamps were 
all " volted," then four of each were run for three and a half 
hours at 65 volts, and for one and a half hours at 70 volts pres- 
sures — 15 and 20 volts in excess of the normal. Two of the 
bromine lamps broke at the end of the run. The results are 
given in the following table : 


Lamps, New. 

After 5 Hours at 65 and 70 Volis. 


C P. 


C. P. 







«4 1 






2^.6 1 
34.8 J 

Vacuum ( 
I^mps. f 

Bulbs all Blackened. 











.... 1 







26.2 1 

97.a f 

Bromine 1 
Lamps f 

Bulbs not Blackened. 






... J 

Comparing the two kinds of lamps, it is seen that all the 
vacuum lamps had fallen more than one-third in candle power 
while the bromine lamps fell only five per cent. The current in 
the vacuum lamps had also diminished, showing an increase in 
resistance of the filaments of over five per cent. 

Two others of the same lot of 50-volt lamps, one vacuum and 
one bromine, were run for five minutes at 90 volts, at which 
pressure the light was of a dazzling whiteness. 

The results are given in Table II. 



Lamps, New. 

After Five Miautes at 
90 Volts. 

Bromine .. 


c. p. 



C. F. 




Greatly Blackened. 
Not Blackened. 

In this experiment also, the vacuum lamp shows a very great 
loss in candle power as compared to the bromine. 

It may be said that these experiments were performed under 
abnormal conditions. They were, to save time. But if the 
bromine will, when the filament is carried to such an abnormal 
incandescence, preserve to such a marked degree the illuminating 
power of the lamp, so much the more should it do so when the 
incandescence is normal. 

But to remove any doubt as to the effect under normal condi- 
tions I have obtained from Mr. Waring the results of a life test 
in progress at the Waring factory, and with his permission I em- 
body them in this paper. The results as furnished me give the 
individual readings for eight vacuum and eight bromine lamps 
all identical in material and construction up to the point of ex- 
hausting the bulbs, when eight of the lamps were taken at random 
to be exhausted as vacuum lamps, and the remaining eight filled 
with bromine vapor in accordance with the regular process pur- 
sued in the manufacture of the " Novak " lamp. 

As these lamps all had similar filaments, the bromine lamps 
would, if run at the same candle power, have been less efficient 
at the start than the vacuum lamps. The bromine lamps were, 
therefore, " volted " for 28 c. p. and the vacuum lamps for 25 c. 
p., and each lamp marked with it^ appropriate voltage. The bro- 
mine lamps varied from 52.4 to 55.8 volts, and the vacuum 
lamps from 50.5 to 52 volts. During the run the pressure was 
maintained for the bromine lamps at 54.15 ; for the vacuum lamps 
at 51.3. At approximately 200, 400, and 600 hours from the 
beginning, the candle power of each lamp was measured at it« 
marked voltage. From the individual readings furnished me, I 
have computed the mean values which are given in Table III. 
on the next page. 




Mean of 8 Lamps 
at o Houn. 

Mean of 8 Lamps 
at a 10 Hows. 

Mean of 7 Lamps 


at 400 Hoars. 

Mean of 6 Lamps 1 


at 6as Hours. 

Vacuum. . . . 



C. F. 




C. F. 




C. F. 




C. F. 

8 Lamps 

7 Lamps Remaining; 

5 Lamps Remaining 

3 Lamps Remaining 









a9 a4 




I One of the 6 vacuum lamps has a very bright spot on the filament, and can only last a few 
hours longer. 

The efficiencies in watts per candle are as follows : 



sio Hours. 

400 Hours. 

695 Hours. 






What is the teaching of these results ? Of the bromine lamps 
one had failed in less than 200 hours, two more in less than 400 
hours, and two more, or five in all, before the end of the test at 
626 hours, but the candle powers of the lamps still doing service 
were even higher than at the beginning. At 400 hours there 
had been no loss of efficiency. At 600 hours the efficiency had 
only fallen about 3 per cent., and even this was partly due to the 
fact that these three remaining lamps were, at the start, below 
the average efficiency. The vacuum lamps on the contrary had 
failed in candle-power nearly 20 per cent, at 400 hours, and 27 
per cent, at 625 hours. In efficiency they had dropped from 
3.47 at the start, to 4.33 at 400, and 4.8 at 625 hours. 

Although only one lamp had failed, those vacuum lamps were 
aU prdcUcaUy dead at IfiO Jiours^ and in comparing their useful 
life with that of the bromine lamps, they should be so considered. 
But in whatever way the comparison is made, the bromine lamps 
in this test will appear as the better lamps, and yet up to the 
point of exhausting the chambers the bromine and vacuum lamps 
were precisely alike. 

These results do not accord with the generally accepted belief 
as to the effect of a gas in the lamp chamber. Again and again 


I have been asked in reference to the claims for the " Novak " 
lamp : — " /y it true that they maintain their candle power ?" and, 
second, with considerable skepticism thrown into it : — "Well, how 
do you account for it ?" This means, that I must submit over- 
whelming proof of the alleged facts, or I must account for them. 
I do not object to this. It would be my own position in a simi- 
lar case. 

I remember once, some years ago, an inventor of a new dy- 
namo asked me to come and see it and give him an opinion of it. 
When I reached his shop he, unfortunately, could not show it in 
opei-ation, but he assured me that his dynamo was a most won- 
derful machine, several times as efficient as any other known. 
He told me that, running it by means of a little engine that 
could not by any possibility give more than two horse power, 
and which also ran his shop, he was able to run thirty-two Edison 
16 c. p. lamps of tlie old eight-to-tho-horse-power type, to full in- 
candescence. It seemed to me it must be a wonderful dynamo 
to develop four horse power from two. I asked him how he 
accounted for it. He could not explain it very clearly, at least 
I could not get the force of his explanation, and, though I saw 
the engine, and the dynamo, and the lamps, I expect I came 
away somewhat skeptical as to the performance of that machine. 

Now I hope to be able to convince you before you go away 
to-night that the facts claimed for these bromine lamps are fully 
in accord with other known facts, even if they do not seem to 
accord with previous theories as to the action of gases in the 
lamp chamber. 

I may say that the fact that there is less blackening in a lamp 
that contains some residual gas is no new discovery. It was 
noted early in the history of the incandescent lamp. Edison 
not«d it and made it the subject of a patent in 1883. Bernard 
8. Proctor, in 1883, states that the manufacturers of Swan lamps 
had found " that these carbon deposits which occur when a lamp 
is overheated occur even more in lamps with the highest v<uma 
than in those less perfectly exhausted." * 

Other observations pointing in the same direction have been 
made from time to time, although the true bearing of the ob- 
servations do not seem to have been recognized. Professor 
Thomas, in a paper read before this Institute, detailing the re^ 
suits of his life tests of various makes of incandescent lamps,^ 

1. 77i« Electrician, London, vol. ix., p. 603. 

2. Transaottgns, vol. ix , p. 271. 


states that he found the lamps exhausted by metallic pumps to 
blacken less than those exhausted by mercury pumps. 

Professor Thomas suggests no explanation, but various refer- 
ences to his paper seem to take it for granted that the difference 
is due to the presence of mercurial vapor in the lamps exhausted 
by mercury pumps. Mr. E. E. Gary, in a note '* On the Blacken- 
ing of Incandescent Lamps," takes this view.* 

1 do not know of any foundation for the belief that mercury 
vapor causes the blackening, or helps to cause it. So far as I 
know, no one has ever demonstrated that mercury vapor exists 
to any extent in the chamber of an incandescent lamp. It cannot 
exist at a pressure greater than about 1-1 5,000th of an atmos- 
phere unless the temperature of the mercury is much above that 
of the pump room. 

Since the degree of vacuum possible by means of a mercury 
pump, is limited by the tension of the mercury vapor, and since, 
as long as any gas is being removed, the flow is from the lamps 
through long narrow passages toward the pump, I do not see 
how it is possible for vapor of mercury in any quantity to find 
its way back from the pump to the lamp. I believe, notwith- 
standing Mr. Gary's statements in the article cited as to the 
degree of vacuum obtained by mechanical pumps, that the greater 
freedom from blackening in lamps exhausted by them, is due to 
the poorer vacuum, and that this is another case of blackening 
prevented by the presence of an inert gaseous atmosphere within 
the lamp chamber. 

Now let us consider the question : Why should the presence of 
a gas lessen the blackening of the lamp ? To answer this ques- 
tion we must first consider the cause of the blackening. 

The coating consists wholly of carbon, no metal deposit ever 
being found except when the filament breaks near its junction 
with the leading-in wires, so forming an arc which vaporizes the 
metal, the vapor formed depositing upon the glass as a metallic 
coating. But as this coating is only formed at the moment of 
rupture of the filament, it has nothing to do with the true " age- 
coating " with which we are dealing. 

The carbon coating is uniformly distributed within the bulb. 

2 The carbon forming the coating must come from the filament. 

1. BUe, Eng., vol. xiv., p. 118. 

•3. See Age-coating in Incandescent Lamps. Prof. E. L. Nichols. Am. 
Jour, of Science^ xliv., 277. 


Is it taken from it by chemical action ? Is it worn off by attri- 
tion by the residual gas ? Is it thrown off by electrical action i 
Is it thrown off as a vapor in consequence of the high tempera- 

Explanations of the phenomena have been based upon all 
these different agencies. 

It has been supposed that the oxygen remaining in the cham- 
ber, combined with the carbon forming carbon monoxid or diox- 
id which was dissociated by contact with the cold glass, leaving 
the carbon as a deposit, while the oxygen returned to the fila- 
ment to combine with more carbon, and so on until the filament 
was destroyed. This, of course, cannot be, since the oxygen 
compounds of carbon are only dissociated at a very high tempe- 
rature, far above that at which they form, and, therefore, far 
above the temperature of the filament. 

The suggestion that the carbon is worn off the filament by 
aii^washing and settles upon the walls of the chamber, never 
seemed to me to account for the continuity and uniformity of 
the coating, and in the light of the facts demonstrated by the 
experiments I have described to-night, the theory of blackening 
by air-washing is untenable, since there is less blackening 
while there must be more air-washing in the bromine lamps. 

The carbon must then be thrown off from the filament by the 
electrical action, or by the high temperature, or by both com- 
bined. In either case it is gaseous carbon^ which will return to 
the solid form wherever it comes in contact with matter at a 
sufficiently low temperature to condense it. Tlds it will surely 
do when it reaches the walls of the chamber, if not before. I 
repeat that, whether the high temperature or the difference of 
electrical potential is the cause of the separation of the carbon 
from the filament ; the carbon that leaves the filament is gaseous 
carbon. I expect this statement will be questioned, and I, there- 
fore, state as fully as possible the considerations that lead to this 
conclusion. It is objected that carbon cannot be vaporized 
except at enormously high temperatures. Also, that in the 
lamp the particles of carbon are projected in straight lines which 
shows the action to be a "Crookes tube effect." What is a 
Crookes tube effect? It is a radiation of the molecules of a 
highly attenuated gas from one of the electrodes of a vacuum 
tube, the exciting cause being a great difference of electrical po- 
tential. Possibly, as claimed by Schuster and others, these 


gageous molecules are separated by the electrical forces into still 
smaller elements, but whether they are or not, will make no dif- 
ference with the bearing of these phenomena upon the question 
under consideration. 

In an ordinary vacuum tube, the passage of the electric dis- 
charge produces a light extending from electrode to electrode 
wherever these may be placed. As the vacuum is improved, a 
dark space will appear around the negative electrode. Appar- 
ently the molecules are repelled so strongly that they are able to 
drive back the body of the gas to a certain distance, but the in- 
evitable collisions finally take up their rectilinear motion and 
convert it into the vibratory motion of luminosity. As the 
vacuum is still further improved, the dark space becomes wider 
and wider, until it reaches the walls of the tube ; the molecules, 
finding no insurmountable obstruction in their path, continue their 
rectilinear motion until stopped by the walls, where the impact 
produces a phosphorescent light. An obstruction within the 
tube , intercepts the molecules in whose path it falls, and casts a 
shadow upon the walls beyond, demonstrating the rectilinear 
motion. The rectilinear motion can also be demonstrated in 
many other ways. But what does the rectilinear motion indi- 
cate ? Nothing, except that the molecules have been projected 
through a space from which all obstructions have been carefully 
removed. I said aU obstructions, but that is not quite true. 
There are still millions upon millions of molecules in the most 
perfect vacuum in our power to make. The flying molecules 
projected from the negative electrode must make their path 
through these, and they can only do so when projected with 
considerable force. For the success of these experiments a great 
potential difference is necessary, — a potential difference meas- 
ured by tens of thousands of volts, — much greater than is needed 
for producing the phenomena of the ordinary vacuum tubes. 

But, for the rectilinear motion and all the phenomena depen- 
dent upon it, we need only a suflScient propelling force, and a 
space sufficiently free from obstructions. The propelling force 
need not be electrical, and the rectilinear motion per se is no suf- 
ficient evidence that electrical force was the exciting cause. 

In the old Edison lamps the filament was copper-plated to the 
platinum wires. When a break in the filament occurred near 
the junction, the arc vaporized the copper and covered the bulb 
with a coating of metallic copper, except that a line of clean 


glass was often left on the side opposite the break, the line being 
the shadow of the unbroken leg of the filament- This is de- 
scribed by Dr. J. A. Flemingl, who says that he has never seen 
this shadow except in the copper deposit, that it is never seen in 
the deposit of carbon. To quote his words : " Hence there must 
^' be some essential difference between the vaporization of the 
" carbon and that of the copper. The carbon deposit resembles 
^' more the condensation of a vapor and is uniformly distributed, 
" but the copper deposit exhibits the character of a molecular radia- 
" tion or shower taking place from a certain point." . He fidds : 
" The whole phenomenon calls at once to mind the beautiful re- 
" searches of Mr. Crookes with vacuum tubes. Here, however, 
" we are dealing not with an induction coil discharge, but with a 
" comparatively low potential." Let us analyze the phenomenon. 
The filament breaks at the copper junction, and an electric arc 
is formed, in which copper is vaporized with comparative ease. 
A large volume of copper vapor is formed almost instantaneous- 
ly in a space almost devoid of other matter. The sudden ex- 
pansion of that vapor is sufficient cause for the projection of the 
molecules in straight lines to the walls of the chamber. It is 
not necessary to assume any refined electricitl forces to account 
for the rectilinear path. The plain old-fashioned, unpretenious 
vapor " tension " that bursts our steam boilers is all-sufficient to 
account for this rectilinear projection across the lamp bulb, when 
there is nothing in the way. 

I might quote many references to show that the carbon de- 
posit never shows a shadow; and Mr. Proctor in the note 
already cited, states that a platinum deposit formed under pre- 
cisely the same conditions as the copper deposit described above, 
never shows the shadow. This, no doubt, is due to the much 
lower tension of the platinum vapor produced at the tempera- 
ture of the electric arc. The so-called Edison effect, which con- 
sists in a derived current through an outside circuit between one 
of the terminals of the lamp and an idle pole placed between 
the two legs of the filament, has been held to demonstrate a 
rectilinear movement of the gaseous matter within the bulb. 
W. H. Preece in a paper read before the Society of Telegraph 
Engineers and Electricians,^ describes experiments which he 
claims prove the rectilinear character of the motion, but either 

1. The Electrician, (London,) xi., 65. 

2. The Electrician, (London), xiv., 486. 


there is some error in tlfe publication of his Qxperiinents, or they 
do not bear out liis conclusions. The paper records the details 
of a number of experiments. In Exp. 6, the idle pole was 
placed in a long tube attached to the lamp bulb opposite the fila- 
ment near the bend, and extending in a direct line from the fila- 
ment. At a very high incandescence a very feeble current was 

In Exp. 7, the idle pole was in a tube sealed to the lamp 
bulb at the top, and then bent at a right angle so that the gase- 
ous molecules which carry the current would have to turn a right 
angle to reach the idle pole. The current developed wan nearly 
the scmie as m Exp, 6, showing that the molecules may turn a 
right angle. This effect has been relied on more than any other, 
perhaps, as demonstrating that the carrying of the carbon from 
the filament to the walls is a " Crookes tube effect," but it only 
shows that an electric current flows through the gas within the 
chamber. It does not show that the vehicle is carbon in vapor 
or in any other form. Indeed, the carrying of a current through 
a gas seems to be an electrolytic action, the molecules of the gas 
being separated into positive and negative ions, which convey the 
current exactly as in a liquid electrolyte. I cannot see that the 
fact that a current is carried from the positive to the negative 
heel of the filament, explains the deposit of carbon. Even if it is 
carbon vapor that carries the current, the fact that no current is 
apparent except at high incandescence would indicate that at a 
lower incandescence there was too little vapor. But whether it 
is carbon vapor that carries the current or not, and whether the 
motion is in right lines or not, I do not see that this experiment 
has any bearing upon the formation of the carbon deposit on the 
walls of the chamber. As I have said before, I attach no signi- 
ficance whatever to a motion in right lines. There is nothing 
peculiar or mysterious about it. Newton's first law says : "Every 
body continues in its state of rest or motion iyi a straight line, 
except in-so-far as it may be compelled by force to change that 
state." All you want is a force to put your molecules in motion, 
and then keep every thing else out of the way and they will 
move in straight lines. All that the rectilinear motion demon- 
strates is the absence of interfering forces ; it does not in any 
way indicate the character of the force that imparted the mo- 
tion. We must look farther in order to determine that. Piob- 
ably in the Crookes tubes the force that projects the molecules 


is largely electrical repulsion, but even here it is open to ques- 
tion. We know that under suitable conditions, the material of 
the electrode is volatilized and the vapor deposited on the walls 
of the chamber or other surface within it. Prof. Wright, some 
years ago,^ investigated the formation of these coatings and pro- 
duced in this way beautiful metallic mirrors. Prof. Crookes, in 
a paper read before the Royal Society, June 11, 1891,^ upon 
"Electrical Evaporation," describes experiments to determine the 
increase in the amount of vapor formed under the influence of the 
electric discharge, as compared with that produced by heat alone 
at the same temperature. Water shows a decided increase in 
evaporation when connected to the negative pole of the coil, and 
metals vaporize at temperatures at which they would not under 
ordinary conditions vaporize at all. 

Prof. Wright, in a private letter to me, states that to obtain 
his metallic mirror deposits, it was necessary to use a small wire 
one-fourth of a millimetre or so in diameter for the electrode, in 
order to concentrate the electric action. This was frequently 
heated- red hot. The best vacuum for the purpose was y^ to 
•yfir of an atmosphere. With a higher vacuum, the metallic 
vapor spread out and deposited all around on the vessel instead 
of being confined to the object to be covered. With the proper 
vacuum, and a coil capable of giving a spark of four or five centi- 
metres in length, the discharge near the electrode is dense vapor, 
which gives usually the characteristic metallic spectrum, and in 
this the surface to be coated must be placed. If placed too far 
from the electrode the deposit is sooty. In this experiment the 
electric energy vaporizes the metal partly by raising the temper- 
ature of the electrode, and partly by the direct action of electric 
forces. The vapor formed is hot enough, that is, the molecules 
separated have motion enough to give the light required for the 
characteristic spectrum. The tension of the vapor is sufficient 
to force back the gas, and almost exclude it from the space near 
the electrode, further away the vapor mixes with the cooler gas, 
the vapor molecules give up to the gaseous molecules some of 
their motion, and then coalesce into a metallic dust that gives a 
sooty deposit on a surface in that region. 

The case is exactly that of the vapor issuing from a tea-kettle 
under atmospheric pressure. The vapor forces back the air and 

1. Am, Jour, of Set., xiii, 49, and xiv, 169. 

2. The Electrician (London), xxvii., 197. 


at a short distance from the spout is pure aqueous vapor. A 
little further away it mixes with the cool ai^ and condenses into 
a cloud of liquid particles. 

But in all these cases where vaporization is aided by electrical 
forces, the results are obtained by the use of great differences of 
potential — thousands of volts ; while in the incandescent lamp the 
difference is never much over one hundred volts. 

And, moreover, all incandescent lamps, whether made for 110, 
50, 30, or 7i volts, blacken when run at an abnormal voltage. 
The blackening depends upon the temperature of the filament, 
and not upon the absolute potential difference in the lamp. 
Surely, if electrical forces played any part in the vaporization of 
the carbon, the effect should be greater in a 110 than in a 7i or 
even a 50-volt lamp. 

Let us consider for a moment the other objection to the vapor- 
ization theory, that carbon cannot be vaporized except at an 
enormously high temperature. What proof is there that it can- 
not be ? The fact that carbon cannot be melted or even soft- 
ened at any temperature we can produce, has been adduced as 
proof that it cannot be vaporized. But there are many solids 
that can be vaporized, although they cannot be melted. 

Ammonium chloride is a notable example. Ice cannot be 
melted in a vacuum, although it will rapidly vaporize. Ice will 
also vaporize rapidly under full atmospheric pressure at a tem- 
perature below the melting point, if the vapor formed is kept 
out of the way by a current of air. 

Depretz, some fifty years ago,' experimented upon carbon at 
high temperatures, first in a vacuum and then under pressure in 
an inert gas. In a vacuum the carbon was rapidly vaporized and 
deposited on the walls of the vessel, and broke before a temper- 
ature could be reached at which it showed signs of softening. 
Under a pressure of three atmospheres, however, in an atmos- 
phere of nitrogen, a much higher temperature was reached, and 
when the carbon rod broke it sometimes bent by its own weight 
in the form of a letter S. He was also able to wdd together 
sticks of carbon by means of the electric current, probably one 
of the earliest instances of electric welding. 

It is a well known fact that in the electric arc, carbon exists in 
the form of vapor. The vapor often condenses on the cooler 
negative carbon, producing a sort of mushroom growth. That 

1. CompUs lUndus, xxviii. and xxix. 


it is not in the form of a finely divided solid in the arc is evi- 
dent from the faint Jumiuosity, and from the fact that the arc 
gives the carbon spectrum. Carbon vapor is, as shown by the 
spectrum, also found in the non-lumino'js base of a coal gas 
flame, but the molecules soon begin to coalesce into carbon dust 
which, raised to incandescence, gives the luminosity to the flame. 
We cannot very much increase the luminosity of a gas flame by 
raising its temperature by forced draft or hot blast, as the in- 
creased temperature prevents the condensation into solid dust 
and may destroy the luminosity altogether. Dr. Nichols ^ has 
pointed out that the temperature of a gas flame is not far from 
that of the filament of a stable incandescent lamp, and called 
attention to the bearing of this fact upon any attempts to im- 
prove the incandescent lamp by raising the temperature of the 

I think the facts and considerations I have brought to your 
notice, show not only that there is no reason for denying the va- 
porization of the carbon filament, but that there is every reason 
for believing that such vaporization takes place, and whether 
that vaporization is aided to any material degree by the electri- 
cal forces or not, it is subject to the same laws as the vaporiza- 
tion of other substances. 

What is vaporization ? Modern theories of the constitution of 
matter assume that the molecules of all bodies are in a state of 
motion. In consequence of this motion, some of the molecules 
at the free surface of some liquids and solids fly beyond the 
sphere of molecular attraction that binds them in the liquid or 
solid form, and when once beyond that attraction they continue 
on in straight lines until turned from their course by impact with 
other molecules or with the boundary of the space in which the 
body is. 

These free molecules constitute the vapor of the substance. 
Place a lump of ice under a bell-jar perfectly void of other 
matter. Molecules will leave its free surface and shoot across 
the space in straight lirws to the walls, where they will rebound 
and on their return may collide with other molecules, or may go 
back and join their fellows in the solid lump. But the number 
of molecules that escape, will exceed those that return until, if 
the temperature be zero centigrade, the pressure of the vapor 
reaches 4.6 millimetres of mercury, at which pressure the return- 

1. Electric Club Pamphlets. No. 24. 


ing molecules will exactly make up for those that escape, and 
the ice will no longer lose. Suppose the bell-jar had contained air. 
It would make no difference to the fact of vaporization. If the 
ice is at such a temperature that the molecules escape at all, they 
will still escape when the air is present, but many of them will 
at once collide with air molecules and be turned back, and the 
result will be that there will soon be so many vapor molecules in 
the layer next the ice, that the returning molecules will nearly 
equal the escaping molecules, and evaporation will take place 
very slowly ; but all the while some molecules of the ice vapor 
will find their way among the air molecules to greater and 
greater, distances, and the perfect balance between the outgoing 
and returning molecules will not take place until, at the same 
temperature, the number of the free molecules is the same as 
before. Suppose in the first instance, when we had the vacuum 
to start with, the bell-jar was kept at a temperature of say — 5°, 
while the ice remained at 0°, some vapor molecules would coa- 
lesce to form frost on the inner surface of the bell-jar, and since 
the pressure of aqueous vapor at — 5° is only 3.1, while at 0° it 
is 4.6 mm. of mercury, there will be a constant flow of vapor to- 
ward the walls until the lump of ice is all gone. If under the 
same conditions, as to temperature, the bell-jar contains air, pre- 
cisely the same thing will take place, except much more slowly. 
If the air in the bell- jar be at — 5° the vapor molecules in their 
collisions with the air molecules will lose some of their motion, 
some of them will coalesce to form frost crystals in the air, and 
we might have a cloud or even a fall of snow. If our lump of 
ice were made the negative electrode of an induction coil the 
agitation of its molecules would no doubt be increased, more of 
its surface molecules might be driven off, and with greater veloc- 
ity, they might go in straight lines to much greater distances 
before being deflected, but it would in no way alter the general 
result. The presence of air would retard both the deposit of 
frost on the walls, and the waste of the lump of ice. 

The bearing of all this upon the action going on in the incan- 
descent lamp is obvious. At the high temperature of the carbon 
filament, carbon molecules do sometimes get beyond the reach of 
molecular attraction. These molecules will, when once they 
leave the filament, if there is nothing in their path, go straight 
to the walls of the chamber. Because of the lower tempera- 
ture of the walls, the molecules will lose something of their 


motion by the impact, and, after sacceseive collisions, will have 
lost so much that they will coalesce and form a coating of solid 
carbon on the walls. 

The condition here is precisely the same as that of the ice in 
vacuo. The free molecules of carbon constitute a true carbon 
vapor. Nothing that we know of carbon warrants us in deny 
ing this, and all we do know favors the conclusion. The maxi- 
mum tension of the vapor is extremely low, equivalent to saying 
the velocity of the molecules is small, hence the presence of a 
gas of low pressure is sufficient to check the motion and cause 
the molecules to quickly accumulate at the maximum density 
near the carbon filament, when the molecules will return to it 
as rapidly as they escape. 

But in the lamp a new condition is met with, one that would 
be hardly appreciable in the bell-jar in our ice experiment. In 
consequence of the great difference of temperature between the 
filament and the walls, convection currents will be set up in any 
gas contained in the chamber. The layer of saturated vapor 
near the filament will be carried away by these currents of gas, 
leaving room for the formation of more vapor and further waste 
of the filament. But there is a great difference in gases as to the 
formation of convection currents and it is, therefore, not a matter 
of indifference what gas is used in the lamp chamber. It should 
be a gas in which convection currents are a minimum. 

Gases of great molecular weight, like bromine and iodine, pos- 
sess the desired qualities, and when used in proper quantity in 
the lamp chamber not only prevent the blackening but retard in 
some degree the waste of the filament. If we could in any way, 
by mechanical means or otherwise, still further check the circu- 
lation of the gas within the lamp chamber, we should still fur- 
ther check the waste of the filament and prolong the life of the 

I call your attention again to the results of the experiments 
with bromine lamps. Under all conditions of running at normal 
or abnormal temperatures they blacken less than high vacuum 
lamps, they also increase less in resistance, and, therefore, for 
both reasons their candle power is better maintained. I have 
shown that this is just what we should expect from all known 
laws of the formation and condensation of vapors. I have, per- 
haps, spent more time than was needful upon the question of the 
electrical agency in the formation and carrying of the vapor, but 


there seemed to be sucli an air of mystery surrounding the 
" Crookes tube effect," or " electric carrying," or passage in 
" straight lines," that I thought it worth while to try and clear 
that up, so far, at any rate, as it relates to incandescent lamps. 
It all comes to this, that electrical vaporization — vaporization 
mainly produced by the direct action of electrical forces — is 
only observed in connection with great differences of potential, 
sufficient to give sparks several centimetres long in air. The 
rectilinear motion is only a consequence of the freedom from in- 
terference. In the incandescent lamp the potential differences are 
small, the temperature is higher than that of a gas flame where 
carbon vapor does exist. Why, then, should it not exist in the 
lamp, as a result of the high temperature alone ? Recognizing 
its formation there, and considering all the various conditions 
that exist in the lamp chamber, it is seen at once that the light 
and mobile gases might, although they prevent the blackening of 
the walls of the chamber, increase the waste and shorten the life 
of the filament, and we are led at once to the selection of a 
heavy and viscous gas. With such a gas in the lamp, and a 
properly proportioned filament, the initial efficiency may be 
carried as high as in the vacuum lamps and the efliciency and 
illuminating power will be well preserved to the end. Since 
the resistance of the filament does not increase, it has not the 
advantage of working at a lower and lower temperature as is so 
often the case with the vacuum lamps, the strains due to sudden 
changes of temperature in extinguishing and relighting the lamps 
are greater because of the higher temperature, and it is to be 
expected that the rupture of the filament will occur earlier in 
its life. But experience goes to show that the bromine lamp 
will outlast the efficient life of the vacuum lamp and give a 
more satisfactory, because a more uniform, service. 



The President : — I will call on Prof. Robb, of Hartford, to 
open the discussion. 

Prof. Wm. Lispenard Robb : — I think I voice the sentiment 
of the Institute in saying that we are indebted to Profest^or 
Anthony for a very interesting paper on a most important sub- 
ject, i have been more and more impressed of late with the 
great need of a lamp of constant efficiency, rather than of a 
lamp of high initial, but constantly decreasing, efficiency. All 
the work oi manufacturers of late seems to have been devoted 
to getting lamps of as high initial efficiency as possible, and con- 
sequently we have lamps whose candle power decreases very 
appreciably from week to week, and month to month. >low, in 
a large room, that does not cause any very great difficulty, be- 
cauge after the service has been going on for some time there 
will be a continual renewal of lamps, and we shall soon get into 
a condition where we will have an average amount of light in 
the room. But in the application of electricity to house light- 
ing, where we have from one to four lamps in a room, it is a 
cause of great annoyance to have lamps, which first give out 
sixteen candle power, and at the end of six weeks or two 
months give twelve candle power. Professor Anthony seems 
to have pointed out a way to overcome this difficulty. I 
confess the iirst lamp I ever saw of tlie Waring company's 
manufacture rather prejudiced me against the lamps. 1 remem- 
ber having a few submitted to me by the Hartford Electric 
Light Company for test, and finding that they required about 
4.5 watts per candle power. That was at the time when the 
Waring Electric Company was using filaments which were manu- 
factured for use in high vacuum lamps. Before shutting down, 
they were manufacturing lamps which had comparatively high 
efficiencies. I have never seen before, the result of any tests of 
Waring lamps made under normal conditions, but thejj^ evidently 
coincide with what was expected from the tests which various 
electricians have made of the lamp under forced conditions. 
There is, however, a certain value to be attached to the tests 
under forced conditions. As is well known, the deterioration in 
candle power of an incandescent lamp is very different on a 
commercial circuit from what it is in an ordinary test on a 
battery. The deterioration is caused to a great extent by the 
abnormally high voltages which are furnished by nearly all com- 
mercial companies at certain times, and the forced tests certainly 
show the advantage of bromine lamps in withstanding this hard 

I fully agree with Prof. Anthony in his opinion that the 
blackening of the bulb is chiefly due to the evaporation of the 
carbon. We have three theories put forward to explain the 
wasting away of the carbon and the consequent blackening of 
the lamp. We have the air-washing theory what we might call 
the Crookes effect theory, and the theory of simple ordinary 


evaporation. Now it seems to me, if it is an air- washing phe- 
nomenon, due to convection currents, this air-washing must be 
nearly proportional to the temperature of the tilaraent. If it is an 
electrical phenomenon, it must be approximately proportional to 
the voltage at which the lamp runs. Now what do we find ? The 
most complete tests that I am acquainted with in regard to the 
efficiency of electric lamps, are an exhaustive set which was 
made at Zurich by Professor II. F. VVeher. to whom we are 
indebted for those extremely valuable tests of the efficiency of 
the Frankfort-Lauflfen transmission plant. I selected at random 
a test of what he denominates the newest Edison lamp. The 
lamp was marked 16 candle power at 100 volts. He states that 
at loO volts and a fracti<»n, it gave 16 candle power with an effi- 
ciency of 3.04 watts per candle power and that the filament was 
at a temperature of 1573° C. At 108 volts and a fraction, he 
gives the candle power as 25.8, the efficiency as 2.25 watts per 
candle power, and the temperature as 1610° C. We have 
there a difference in voltage of eight volts, and a difference in tem- 
perature of 37 degrees. Now it seems to me that a difference in 
temperature of 37 degrees in that part of the scale, that is from 
1573° to 1610°, would not produce any great difference in air- 
washing — anything like enough to account for the difference in 
the rate of blackening of the bulb of the lamp when run at those 
two different efficiencies, at 3 watts per candle power and at 2^ 
watts per candle power. Nor could a difference of 8 volts, from 
100 to 108 volts, cause sufficient difference in any electrical 
phenomenon to cause the great difference in the rate of blacken- 
ing. But it seems to me that the rate of evaporation at those 
two different temperatures could be very different. If we con- 
sider the evaporation of ice, or what bears more fully on this 
subject than any other research I know of, one by rrofessors 
Kamsay and Young on rate of evaporation of camphor under 
different pressures and at different temperatures— we shall find 
that a very slight difference in the pressure, or a very slight dif- 
ference in the temperature, when you are at a certain point on the 
scale, can cause a very great difference in the rate of evaporation. 
It seems to me, therefore, that of the three explanations, that is, 
air-washing, the Crookes effect and evaporation, the theory of the 
wearing away of the carbon by evaporation pure and simple is 
the one which is most in accordance with the experimental facts. 

The President :— Gentlemen, before calling on the other 
members for remarks, I would say that I have two communica- 
tions here, one from Professor Elihu Thomson and the other 
from Mr. Edward P. Thompson. Is it your wish to hear these 
before the rest of the discussion or subsequently ? 

Dr. Pupin an:l others : — Before. 

The President: — In the absence of the Secretary I will read 
them. This is from Professor Elihu Thompson. 

Prof. Elihu Thomson : — The facts and reasoning put forward 


iu Professor Anthony's paper are the more interesting to me, as 
his conclusion as to the cause of blackening of bulbs or ^^ age 
coating," agrees with my own view of the matter, a view which 
I have had for several years, and which I brought out last year 
in a paper on the Life of Incandescent Lamps in the Lehigh 
QuaHerly (Lehigh University). It has been known for a long 
time past that the very highest vacuum was not so beneficial to 
the life of lamps as a more moderate exhaustion ; and Mr Edison 
patented the use of a residual chlorine atmosphere in about 1883. 
A residual bromine or iodine vapor would appear to be possibly 
better than chlorine, but in the same line of work, and owing to 
the close chemical relations of the three elements, any effect ob- 
tainable with one might be expected to be obtained in a greater 
or le88 degree from the substitution of another, or even the sub- 
stitution of two others together in the bulb. A mixed bromine 
and iodine vapor may give even better results, or a mixed chlo- 
rine and bromine or iodine. After all, the merit of such admix- 
tures, or even of the use of a diluent like bromine, may require 
some further experience to settle. It is a well known fact that 
incandescent lamps starting with a rather low vacuum often im- 
prove their vacuum automatically during the run. My opinion 
as to the cause of this improvement has long been, that the firet 
beginning of the production of soot or separation of solid carbon 
at normal potentials, causes, by the separated carbon particles, 
absorption of the residual gas so as to improve the vacuum. 
Fine carbon has, as is known, a powerful gas absorbing ten- 
dency, and although the amount formed may be so slight as to 
be totally imperceptible in the bulb, it may still be present in 
sufficient quantity to have the effect noted. 

The bearing of these facts on the sustained brilliancy of a 
lamp started with a lower vacuum is evident. If the gas pres- 
ent he gradvaUy taken np, the efficiency of light p7*oduction 
will rise and compensate jor the change in the filament as the 
time goes hy, 

I agree with Professor Anthony, and my views were brought 
out in the papei* above referred to, that the age coating is more 
evidently due to simple vaporization of carbon, than to the many 
causes which have been assumed for it. I quite agree with him 
that the carbon leaving the filament is vaporous, i)ut I think it 
must condense at once just outside the filament, and not pass out 
into the bulb as vapor in ordinary cases. I have a ^hvolt incan- 
descent lamp in my possession which was accidently connected 
for a moment to alternating mains of large carrying capacity of 
1,000 volts potential difference. The lamp actually survived the 
shock, and is in good condition with one exception. While the 
bulb glass is perfectly clean and clear, there exists a flocculent 
mass of soot which is coherent and falls about within the lamp. 
It is a comparatively large mass, and at first surrounded the fila- 
ment as a delicate mantle, evidently formed by a dense evolution 


of carbon vapor coDdeDsing immediately around the carbon in 
the vacuous space. Here the age coating (?) was too dense to 
reach the sides of the bulb. The lamp, however, is a significant 
example of the normal action of vaporization highly intensified. 
The nlament retains its steely lustre. 

Contrary to the statement of the paper that no shadow on the 
bulb is ever formed, except from the metal vapor, I am confident 
that I have seen it in series lamps when the carbon broke, and in 
cases of as sudden evolution of carbon vapor as of the metal 
vapor from the supporting wires. In a good vacuum, the carbon 
vapor condensing would give particles which would move in 
rectilinear paths as the metallic vapors. The shadow effect is 
dependent on a local evolution of vapor, with a part of the wire 
or filament between the point of evolution (as the joint) and the 
opposite glass surface. It would not be expected where the 
evolution of carbon vapor is nearly uniform from all parts of 
the carbon filament as m the normal wear of the carbon. I am 
also confident that I have seen platinum shadows, where only 
platinum and no copper was present with the carbon. 

As bearing on the statement of the paper that the carrying of 
a current through a gas seems to be an electrolytic action, and 
confirming the same, I may say that I have a lamp which has 
copper terminals in the bulb, and which shows attached to the 
copper wires, fine hair-like or leaf -like projections, evidently pro- 
duced by current passing the vacuous space between the wires 
and carrying copper, the development resembling lead and other 
metallic trees formed by electrolysis of solutions. Lamps have 
been known to short-circuit from this cause. 

I, at one time, experimented on arcs formed between metal 
electrodes in a highly vacuous chamber, and found that it was 
easy to coat objects with metallic shining mirrors— silver giving 
a very bright coating. With a large current the effect is instan- 

The paper states that " The fact that carbon cannot be melted, 
or even softened, at any temperature we can produce, has been 
adduced as proof that it cannot be vaporized." This is not 
strictly a correct statement. Carbon can readily be softened and 
bent at temperatures approaching that of the positive crater of 
an arc lamp, as I have proved conclusively. I have some bent 
sticks in my possession made from straight sticks of five-six- 
teenths carbon. The carbon in the crater of a large arc is always 
soft and putty-like. As a matter of opinion, I think that carbon 
will readilv melt when subjected to the highest incandescence 
surrounded by inert gas at very high pressure. I am not aware 
that the experiment has yet been tried under extreme conditions. 

I think no one now doubts that the arc stream, or flame be- 
tween the carbons of an arc lamp, is due to carbon vapor and 
not to carbon particles evolved from the crater surface. 

I am glad that Professor Anthony has put forward in such a 
clear and comprehensive manner, the arguments showing that 


slow evaporation of solid carbon is the true cause of lamp bulb 
blackening. How often it is that complicated theories are put 
forward to account for simple facts, when at last it may be found 
that such theories were never needed. Little lurther proof is 
needed to establish the fact that simple evaporation at the high 
temperature amply accounts for wear of carbon in incandescent 
lamps, and for crater emanation in arcs. 

Mb. Edward P. Thompson : — The author has alluded to the 
question as to whether any injurious action takes place between 
mercury and highly incandescent carlwn. 1 made repeated and 
crucial experiments upon this subject, but have not heretofore 
published an account of them. They may, perhaps, be appropri- 
ately considered as a part of this discussion. Professor Anthony, 
as I remember, states that it does not seem probable that mer- 
cury vapor exists in the lamp, which during exhaustion has a 
direct connection with liquid mercury. One object of my ex- 
periment was to be absolutely sure that the filament was in an 
atmosphere of mercury, and then to turn on the current and raise 
the temperature to whiteness, probably 3,000°; I, therefore, put 
mercury into a lamp and boiled the mercury for half an hour, let- 
ting the excess of vapor pass out of the lamp. The boiling was 
effected by burying the lamp bulb in sand which was heated 
greatly ai)ove the boiling point of mercury. At tir^t the 
air was crowded out, then a mixture of air and mercury, 
and finally, nothing but pure mercury vapor and boiling mer- 
cury remained in the bulb with the filament. The vapor could 
be seen issuing at a distance from the outlet, and further still, 
condensing upon a cold surface. The filament was. therefore, 
surrounded by an atmosphere of mercury. In such a state the 
current was passed through the filament, which did not burn up 
in the mercurial atmosphere, as it would have don^ in oxygen or 
many other substances which are combinable with mercury. 
Perhaps no better condition can ever be obtained for practically 
proving that mercury will not combine freely with carbon 
directly at a high temperature. The atmosphere was rich in 
mercury, being actually all mercury. The filament was at a 
white incandescence. The experiment was continued for half 
an hour, and was. repeated with different lamps twenty-five times. 
These experiments, as thus far described, proved certainly that 
carbon and mercury do not freely combine ; but how about a 
slow combustion? While the mercury was escaping, the lamps 
were sealed and cooled, and the mercury allowed to run into a 
little tube extending from the lamp, so that this tube could be 
sealed off, and the remaining mercury liquid thus removed from 
the bulb of the lamp. These lamps lasted almost uniformly 
only about fifty hours, because the filaments were slowly con- 
sumed by the mercury vapor. The condensation of the mercury 
had left so perfect a vacuum as to the air, that a trace of the mer- 
cury vaporized and formed an attenuated atmosphere of mercury. 
This result agrees with those of others made in other directions. 


For example, it has been noticed by those who exhaust lamps, 
that it is not well to continue the exhaustion too long for the 
lamps do not last so long, and the reason is thought to be that 
when the vacuum is too complete, a point is reached wliere the 
mercury of the pump vaporizes and surrounds and destroys the 
filament. Mercury appears, therefore, as one of the heavy gases, 
which should not exist in an incandescent electric lamp. 

Mr. John W. Howell: — In my discussion of Prof. Anthony's 
paper, T will consider first the blackening of lamps, and then the 
effect of heavy gases in lamps. The theory which Prof. Anthony 
has set forth in regard to the blackening of lamps by evap- 
oration, has been accepted as the proper explanation of one kind 
of blackening by lamp manufacturers. But all blackening is not 
caused by evaporation as I will show later. Carbon filaments can 
be softened very easily. If a little weight be fastened at the end 
of the loop of a filament and it be run at a pressure a little 
above its normal, it can be bent in any shape. The filament will 
be just as rigid in its new position as it was before. I have seen 
an incandescent filament in an upright position so softened by an 
excessive current that it would not sustain its own weight ; it 
wilted, so that the parallel legs crossed one another. When the 
current was turned off the carbon was perfectly rigid in its new 
position. The molecules of carbon set free by evaporation, fiy 
from the filament as Prof. Anthony says, in straight lines They 
are projected from every part of the filament and do, contrary to 
Prof. Anthony's opinion cast shadows on the globes. The reason 
why they do not cast shadows in most lamps is that the filament 
is not all in one plane, they are twisted somewhat, so there is no 
part of the glass that is shielded by one leg from molecules pro- 
jected from the other. But if the two legs of the filament are 
in thfe same plane it will make a shadow always. I have lamps 
here which snow carbon shadows very distinctly. I have them 
both large and small ; but I think the large ones are more easily 
seen than the small ones. That lamp [showing] has a complete 
shadow entirely around it; a complete line from which half 
the blackening is shielded. There is blackening in incandes- 
cent lamps which does not proceed from the filament in rectilin- 
ear lines and which is not caused by evaporation. I will show 
a lamp which has very plain evidence of blackening in it, in 
such a position that it could not possibly have proceeded in 
straight lines from the filament, because there is a piece of glass 
inside the lamp, the underside of which is blackened, where it is 
completely shielded from the carbon. 

Here [snowing] is a lamp which has a line which looks like 
the shadow of the filament, but which passes around the lamp in 
a plane perpendicular to the plane of the filament. I would like 
to have some one account for it ; I am eure that I cannot. 

Here [showing] is one that has several bands running around 
the lamp in this way. I would be very glad to have Prof.' 
Anthony explain the blackening of this lamp. 



This [showing] is an incandescent platinum lamp — it shows a 
well defined shadow caased by evaporation. 

Blackening is not the chief cause of the fall of candle power 
in lamps; some lamps lose their candle power and show very 
little blackening, while other lamps get quite black and lose little 
candle power : 115 volt lamps will lose their candle power and 
blacken very little indeed. This loss is due to changes in the 
structure oi the filament, or in its surface, which reduce the can- 
dle power considerably with very little blackening. The fila- 
ments of low volt lamps are much more stable than the filaments 
of high volt lamps ; low volt lamps often show considerable 
blackening with very little loss of candle power. 

The effect of gases in lamps is well known, and is clearly 
stated in patents of Edison and Scribner. Gases have not been 
used commercially in lamps, because the results of experiments 

Fio. 1. Vacuum Lamps (32 c. p. 52 volts.) Tested at Lynn. 

have shown, to the satisfaction of the people who made them, 
that the total effect of a gas in a lamp was disadvantageous. In 
the exhaustion of lamps, gases are very often left in the bulb, 
and the amount of gas in the bulb has a very great effect on the 
candle power curve of the lamp. A lamp which is perfectly 
exhausted should give a candle power curve which is a straight 
line. The angle between this line and the datum line indicates 
the quality of the filament. If a lamp is not perfectly exhausted 
this will not be a straight line. The effect of the residual gases 
in the lamp is to change the character of the candle power curve 
of the lamp. The vacuum will improve as the lamp is burned. 
The cooling effect of the gas will diminish and the candle power 
will rise, and then go off m a straight line. The amount of this 
rise of candle power will depend on the amount of gas in the 
globe. A rise of 30 per cent, in candle power can be produced 




in this way. If too much residual gae be left in a lamp, the op- 
posite effect will be produced, the candle power will fall at first, 
then rise a little, and finally start off in a straight line. These 
effects are produced by the residual gases which are left in the 
lamp in its normal exhaustion, not bv other gases, such as bro- 
mine. The lamps from which Professor Anthony makes his 
tables are 64-volt lamps of 26 and 28 candle power. Those are 
the very best type of lamps which can be made. A 64:-volt 
lamp is as good a lamp as can be made, much better than a similar 
high volt lamp. A 32 candle power or a 28 candle power lamp is 
better than a lower or higher candle power lamp. In manufactur- 
ing lamps there are reasons why you would expect better results 
from a 50-volt 32 candle power lamp than almost any other kind 
of lamps. In the bromine lamps and vacuum lamps which 
Professor Anthony compares there are two differences. One has 











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Fio. 3. Novak Lamps (16 c. p. 115 volts.) Tested at 8i W. per candle. 

an atmosphere of bromine, and the other is a vacuum lamp. 
There is also another difference, which is not stated in the paper, 
and which I infer from the knowledge of the Waring process, 
which was brought out in the late litigation between the Waring 
company and the Edison company. This difference is due to 
the fact that the bromine lamps are exhausted without current. 
The occluded gases which are driven oat in ordinary conditions 
of exhaustion are allowed to remain in those lamps. These bro- 
mine lamps are exhausted cold. The bromine is passed through 
them a couple of times and then they are sealed off. The re- 
sidual gases which are left in these lamps produce the variable 
effects! have referred to, so that in the comparison between the 
bromine lamps and the vacuum lamps as he made it, there are 
two differences and not one. We have two experiments carried 
on at the same time, and all the effects credited to one of them. 



Tliese bromine lamps which ProfeBsor Anthony tested which 
ran for 600 hourij and maintained their candle power, would 
have been excellent lamps if they had not broken so quickly. 
Their breakage is very normal. But the vacuum lamps he com- 
pares with them are poor lamps. The comparison is not made 
between the best vacuum lamp and the l>est bromine lamp 

I have a curve [Fig. 1] showing the results of a test made on 
good vacuum lamps of 5ii volts and 32 candle power. The his- 
tory of these lamps is as follows : When the consolidation oc- 
curred between the Thomson- Houston and the Edison companies 
there were two lamp factories in operation, one at Harrison and 
one at Lynn. In order to compare tlie methods in use at the 
two factories, lamps were made in each place and sent to the 
other place for test. The Lynn people sent us lamps and we 
tested them in comparison with our lamps, and we sent them 
lamps which they tested in comparison with their lamps. We 


Fig. 3. Novak Lamps. 

made several kinds, and I will show you the curve of the 50- volt 
32 candle power lamps. The tests were made at Lynn by people 
who were somewhat opposed to us and who would not favor the 
lamps. These are good vacuum lamps of 60 volts and 32 candle 
power and are fit to compare bromine lamps with. They tested 
18 lamps which were run for 1,000 hours and no lamp broke. 
The candle power is plotted in percentages of the initial candle 
power. The candle power at the end of 100 hours had risen 15 
per cent., and at the end of 1,000 hours it was still above 100 per 
cent. No lamp there had fallen as low as it originally started, 
and at the end of 1,000 hours no lamp had broken. This is a 
very remarkable result and could not nave been obtained from 
high volt lamps. These lamps are good lamps of 50 volts 32 
candle power and will bear comparison with the lamps which 


Prof. Anthony shows as good bromine lamps. But the vacuum 
lamps he tested were not good lamps. 

'Ine efficiency of these lamps is shown on these lower lines. 
They are practically stiaight lines. They started at 3 watts per 
candle and at the end of the test they were still 3 watts per can- 
dle. These are ideal lamps, according to Prof. Anthony, in all 
bnt one respect — they did not break. But why does the author 
make short life one of the chaiacteristics of his ideal lamp ? 

These tests which Prof. Anthony quotes would not satisfy me 
if I were having tests made in a factory. He took lamps which 
varied three or four per cent, in voltage and tested them at an 
average voltage. In making lamp tests every lamp should be 
'Set up at its own proper voltage. There should be no averaging 
of voltages ; some of those lamps were burned at a higher pres- 
sure than their normal rating and some at a lower pressure. 
You will find that those burned at the higher voltage than their 
rating broke, and those burned at a lower voltage lasted, and of 
the lamps which at the end were ^29 candle power there was one 
rated originally 55.8 volts which was burned at 54.15 volts. 
That lamp was not burned at 29 candles at all; it was burned at 
23. When they tested for candle power they raised this lamp 
to 29 candles. I would not be satisfied with that kind of testing. 
I admire one thing about this test. The pressure was held con- 
stant to 1-IOOof a volt which is extremely accurate work, and 
not in keeping with the rest of the work done. 

I have been speaking of 115- volt lamps and 55-volt lamps. I 
have made tests of a great many Nov^k lamps. During the late 
unpleasantness between the Waring Electric Company and the 
General Klectric Company we bought a great many lamps direct- 
ly from the factory of the Waring Electric Company. 1 had 
them tested in the factory under my supervision, but J did not 
test any 50- volt lamps. We generally test 11 5- volt lamps or 
thereabouts ; it is the most usual type of lamp sold. It isalso a hard 
lamp to make. I have brought with me results of some tests on 
Novak 115-volt lamps and you will find they are very diflrerent 
from curves on 50-volt lamps. 

There \¥\g. 2] are curves of 19 Novak lamps of 16 candle 
power 115 volts. They were tested at 3i watts per candle. The 
candle power I represent here in percentages. They start at a 
candle power which is designated by lOo per cent ; they do not hold 
constant at all. They drop right down. They also break very 
rapidly. The breakage is marked on the curves. At 500 hours 
they were half gone. It took those lamps just 250 hours to arrive 
at the candle power at which Prof. Anthony to-night describes 
lamps as practically dead. Referring to his vacuum lamps, he 
states that at the end of 400 hours they are practically dead. At 
that time they had reached 80 per cent, of their original candle pow- 
er. These lamps reached that point at 250 hours and they are bro- 
mine lamps. I do not consider them dead, however. 1 do not 


agree witli him at all that a lamp which has lost 20 per cent is dead. 
I think he is entirely wrone in saying that a 25 candle power lamp 
which has fallen to 20 candle power is practically dead. 

In tests which I have made on bromine lamps I found quite a 
variation in the early part of the curves. I mean the curves 
which I sketched on tne blackboard as the curves due to residual 
gases. It is natural to expect a variation in that curve because 
the residual gas is left in it and in combination with other gases 
it causes rather erratic movements. Figure 3 shows the per- 
formances of two individual lamps. These lamps belong to a lot 
which I set up for test which when averaged up made an average 
uniform curve. The two lamps started together. Their candle 
power is represented by 100 per cent. At the end of 35 hours one 
lamp had gained'28 per cent, in candle power and the other lamp 
had lost 2^ per cent. At the end of 35 hours two lamps which 
started together diflEered 48 per cent, in candle power. The 
lamp which rose 38 per cent, then fell off, and the lamp which 
fell 20 per cent, rose again, according to the theory which I have 

Bromine gas in a lamp undoubtedly is an advantage in pre- 
venting bladf ening. In the lamps that I tested there was very 
little blackening. But I do not agree at all with Prof. Anthony 
that it also prevents the wasting away, or change in resistance of 
the carbon. At least it does not on 115-volt lamps. These 
115-volt Novak lamps increase in resistance very materially — 
they increase in resistance more rapidly than good vacuum lamps. 
I do not know of any other advantage which a bromine gas or 
any other gas has in a lamp, except preventing blackening. It 
does not prevent the fall in candle power. It does, however, 
have some disadvantages. A gas in a lamp conducts heat, and 
you have got to run the lamp at a higher candle power in order 
to get its original eflSciency. That necessarily shortens the life 
of the lamp, as is abundantly shown by the experience of the 
lamp up to date. It does not prevent the disintegration of the 
filament. The resistance increases very materiallv, and the candle 
power drops fully as rapidly as it does in a good vacuum lamp. 
It is my opinion, and I believe that all the facts which are known 
and which are before the public to-day in regard to the bromine 
lamp confirm that opinion. Indeed, 1 state it as a fact that the 
weight of evidence is in favor of the conclusion that the disad- 
vantages of the bromine vapor are greater than its advantages. 

I am sorry that the author came nere with such meager data. 
I think he should have come here better prepared. He should 
have had curves which he made himself, not on a few lamps, but 
on a good many lamps of a good many varieties, and especially 
he should have presented tests on 115-volt lamps, because those 
lamps are far more generally used than others. It is the t^st of 
the lamp-maker's skill to make a good 115-volt 16 candle power 
lamp. If any man comes to me and says " I can make an im- 


provement in lamps,'' I would say, " Make me lamps of 115 volts 
and 16 candle power." If any process, bromine or other, can 
produce 115- volt 16 candle power lamps which will show a good 
candle power curve, I will be the first man in the room to 
acknowledge the great advantage in the process. 

Mr. Hahmek : — I wish to make just a remark upon one point 
which Mr. Howell and Professor Elihu Thompson have already 
dwelt on. Sometime ago I made an examination of over 600 
lamps, which had been made at various periods during the last 
13 or 14 years. I have here a list of 12 of the different makers' 
lamps, representing 50 in all. Every one of these shows the 
" phantom shadow." I think it is unquestionably a fact that 
every lamp in which there is this blackening will show a phan- 
tom shadow, provided the carbons are in alignment, notwith- 
standing the statement in the paper. I have here a number of 
photographs of some of these "phantom shadows." Some of 
these photographs have been made of lamps in which the 
" phantom snadow " is scarcely visible to the naked eye, but 
photography has brought it out distinctly. 

There is another matter I am requested to mention that has no 
connection with this subject, but it is a very important one. To- 
night there is a meeting of western members being held in the 
city of Chicago, the first which has been organized under the 
plan adopted in November. The meeting has probably just 
been called to order. The paper which has been presented here to- 
night is being read and discussed there. Through the courtesy of 
the American Telephone and Telegraph Company, the Metropol- 
itan Telephone and Telegraph Company, and the Chicago Tele- 
phone Conapany, the long distance telephone line between New 
York and Chicago, a thousand miles in length, has been placed 
at the disposal of the American Instiiu ie of Electrical En- 
gineers, tnus bringing the two meetings, although a thousand 
miles apart, into close communion. 

The President is requested to step to the telephone and shake 
hands, metaphorically speaking, with the Cnicago members. 
It is only fair in this connection to remember also that the Met- 
ropolitan Telephone and Telegraph Company, has for some time 
past, placed at the disposal of the American Institute of Elec- 
trical Engineers a telephone exchange connection without 
charge. This is spoken of as I think it is a courtesy that the 
members should be aware of. Many of them do not know that 
thev can avail themselves of it in calling up the Secretary. 

X)r. Hutchinson : — I move that the President be requested to 
extend the congratulations of this meeting to the Chicago meet- 
ing. [The motion was carried.] 

The President : — Is it your wish that I should call a Vice- 
President or some one to the chair so that the discussion should 
?o on while I extend the congratulations of New York to 
Chicago ? 


Mr. Hammer : — I think that is an excellent suggestion. 

The President: — Will Mr. Kennelly take tne chair for a 

[Vice-President Kennelly took the chair.] 

Mr. S. E. Doank: — At the time of the consolidation of the 
Thomson and Edison interests, Mr. Howell and I were very 
much gratitied to find that we so well agreed in our deductions 
from tests made independently. My part of the discussion to- 
night will be to confirm, with all the weight that my confirma- 
tion can give, what Mr. Howell has said. We made these 52- 
volt 32 candle power curves. I brought them to Harrison from 
Lynn a few months ago. All makes of 52-volt 32 candle power 
lamps do not behave like these. The lamps were excellent lamps. 
Previous to the appearance of Novak lamps, the Thomson-Hous- 
ton company tested independently for their own information, 
various gases in the bulbs of incandescent lamps. Chlorine, I 
think, was the heaviest gas we used. These lamps behaved very 
much like ordinary lamps exhausted to various degrees. The 
candle powers rose, as Mr. Howell has shown, and then fell 
again. In other words, the effect was exactly as if in making 
initial measurements you had placed a resistance in series with 
the lamp, and had measured the voltage around both lamp and 
resistance, taking other measui'ements, candle power, etc., as if 
the resistance was not there, and then had made your future 
measurements, and had run your lamps with the resistance re- 

The candle power of the lamp ought not to rise extremely 
and it ought not to fall extremely. The ideal lamp, as Professor 
Anthony has told us to-night, is a lamp in which the candle 
power is maintained practically constant. If the candle power 
be allowed to rise, it should not get beyond the point at which 
the carbon is stable. In the case of the 52-volt 32 candle power 
lamps, in this test it did not. With this in mind there may be 
no objection to allowing a vacuum slightly inferior to that which 
it is possible to obtain. 

Concerning the blackening of incandescent lamps, it has long 
been a theory of the Thomson-Houston factory, and I think of 
most manufacturers, that this is due entirely to evaporation. 
Not knowing Prof. Thomson was going to discuss this paper I 
brought down an abstract from the article he refers to, in which 
he says : — " The writer has long been convinced that in a well 
^'exhausted lam pit is due almost entirely to evaporation by high 
*' temperature. Jiist as ice near its melting point and even far be- 
*' low that, evaporates in vacua and even in dry air, so carbon, 
*' practically fixed at low temperatures, acquires in vacua a certain 
*' volatility at an increasing rate with the temperature " 

Concerning the blackening of the lamp, as being the distillation 
of carbon, it is of course known that with filaments partially car- 
bonized, the lamp bulb will blacken because of gas thrown off by 

1894.] DISCUSSION m NEW YORK, 168 

completing the carbonization. But it is a fact, appreciated I 
thinK by lamp manufactnrere, that the deposit made by hydro car- 
bon has practically^ constant physical characteristics. Its specific 
resistance is practically a constant, and this being true, demon- 
strates that there is a chance for improvement on the distillation 
theory. The theory concerning the volatility of carbon seems 
about the only theory at present that satisfactorily accounts for 
the blackening of incandescent lamps. 

This morning in looking over a lot of Novak lam| s that had 
not been opened from the original package from the time they 
left the Novak factory, we selected and lighted a number of lamps 
and I give you as an indicative sign of those tested, the result on 
one only. It was a 110- volt 1 6 o. p. lamp and was run on a forced 
test, at 140 volts which was about equivalent in per cent, increase 
in voltage to the 65-volt tests shown by Prof. Anthony this evening. 
At the start this lamp took .757 amperes. After running live min- 
utes it increased to .799. The candle power increased in this time 
from 59 to 71. This was a forced test. The cause of this was not 
the change in the resii^tance of the filament. It was not due to a 
depositing action, for the resistance increased a little. The change 
was simply due to the improvement in the vacuum which we 
noticed from time to time by tests on an induction coil. 

Had we continued this test, we would have found that after a 
while this Iftmp fell in candles and it would, had it lasted long 
enough, have again reached its tiist candle power. Had we 
made only the hrst and last measurements, we could have said 
the candle power had been maintained constant throughout the 
run, while really it had fallen at least 17 per cent. It was the 
same in effect as if we had treated a 71 c. p. lamp as I instanced, 
that is, as if we had made the initial test with a resistance in- 
cluded in the wires. Of all lamps in which the candles rise at first, 
the rise occurs so soon that forcomparison with others they may be 
considered to have started at the candle power and time when the 
candle power attains its maximum It is highly important, there- 
fore that we should have frequent measurements during the early 
life of a lamp that we may be able to interpret properly the ob- 
served facts of its later existence. 

The figures shown us by Prof. Anthony are open to serious 
criticism for this reason, as well as for otlier reasons mentioned. 
We do not know, according to the above, the candle power these 
lamps really were. The results shown, are average results of 
quite different lamps and the maxima candles probably varied 
even more than the initials, which still further qualifies the fig- 
ures presented. 

Mr. Theo. J. W. Olan : — I should like to call your attention 
to some facts, one of which is that dioxid of carbon in connec- 
tion with carbon at white heat will take up one equivalent of 
carbon and be transformed into monoxid of carbon. Another 
fact is that if we lead oxide of carbon through a tube that is 



heated to a yellowish white, there will appear ae a result in a 
portion of the tube a carbon deposit and dioxid carbon mi^ed 
with carbon dust will pass out of the tube. I see that this can 
account very reasonably for this phenomenon of the blackening 
of the globe, just as well as all the other theories that have been 
advanced to-night. If we suppose that we have at the beginning 
pure oxygen together with carbon in the globe, dioxid of car- 
Don would first be formed. This dioxid of carbon would, how- 
ever, in its turn, combine with more carbon, and the result 
would be monoxid of carbon alone. But at a limited distance 
from the filament we have that heat which may be said to corres- 
pond to the yellowish white hot tube. At that temperature this 
monoxid of carbon would be transformed into carbon and diox- 
id of carbon. That carbon deposits on the globe and the diox- 
id of carbon attacks the filament again. I do not think we can 
accept such a theory as that the carbon filament should consist of 
hydrocarbons which was said in the revelation we heard to-night, 
simply because that seems to stand in opposition to all previous 
experience. I have made many tests myself, and I have read the 
results of other experiments also, and from those I conclude that 
it is not at all diflScult to completely decompose by heat a heavy 
hydrocarbon. If we exclude the air we will have as a last result 
from such decomposition a substance that can be called pure car- 
bon. One cannot at least discover any lessening in* weight by 
heating it more and more. That tends to prove that it cannot 
very well be a series of hydrocarbon that remains in the filament 
when the lamp is ready. But in accordance with what I have 
before mentioned we can easily account for several of the other 
phenomena that have been spoken of here to-night. We heard, 
for instance, that where a bulb is filled with bromine gas, there 
will be no blackening of the glass. Why ? Because bromine is 
one of those few elements that will not directly combine with 
carbon at any heat or as far as known under any circumstances. 
Should it not therefore be possible to conclude just from this, 
that the chemical action has something more to do with the 
blackening of the globe than has been suggested to-night? I 
think so. I will not say that the other suggestions cannot have 
any bearing on the matter. Still I think that the chemical reac- 
tion is to be considered in the first place. Now, it is a fact, that 
in the lamps we have generally oxygen, also nitrogen; we have 
finally a little hydrogen originating from moisture. I would not 
say it is a fact known by everybody, but at least it is stated in 
the handbook of chemistry written by authorities, that nitrogen 
at a very high temperature will combine with carbon just as well 
as oxygen and we nave therefore in that fact another possible 
cause^^ior the blackening of the globes as a result of chemical re- 
action. Even hydrogen, under influence of the electric current, 
can with carbon directly form a hydrocarbon. I think that it is 
too early to make a conclusion witn reference to any one of these 



many suggestions we have had, until we have paid thorough at* 
tention to them all, and I cannot find that in the theories ad- 
vanced to-night by various gentlemen there was anything at all 

Mr. E. a. Colby : — Mr. Howell in his remarks a few moments 
ago, said that he thought there was no question but that bromine 
gas reduced the blackening or deposition of carbon upon the 
bulb, but that he knew of no other use that could be made of 
this gas. I found some eleven years ago when making lamps 
of 125 candle power — which were lamps of relatively liigh po- 
tential — 125 volts, that there were senous troubles, in the con- 
struction of such lamps due to short-circuiting, and the only way 
in which we could overcome that difficulty was either to not ex- 
haust the lamp to the same extent that we ordinarily did a low 
candle power lamp, or else having exhausted the air, to leave 
within the lamp bulb some inert gas. This was in Mr. Weston's 
laboratory in i^'ewark, New Jersey. We tried at that time a 
great many different gases, amongst others, bromine and several 
of the chlorine compounds. We finally concluded, as a result 
of a long series of experiments, that the most suitable vapor to 
use in this connection was that of chloroform. Chloroform be- 
ing somewhat rich in carbon, would, of course, upon entering 
the bulb (the filament being at the temperature of incandescence) 
be decomposed, and carbon would be deposited on the filament, 
whilst the nascent chlorine would combine with any mercurial 
vapor which might be present in the bulb. As a matter of fact 
we obtained within the bulb quite a heavy deposit, white in color, 
and resembling in all its physical characteristics, mercuric chlo- 
ride. This deposit was so heavy that the filament itself 
was at times concealed from view very much as it is in an opales- 
cent globe. To remove this deposit we applied a Bunsen burner 
in the ordinary way, and immeaiately the deposit was vaporized 
and the bulb was *left clear But the important point in this 
connection was this, that the difficulties wnich we had experi- 
enced previous to this treatment, viz., short-circuiting, had en- 
tirely disappeared, and whatever blackening we had been troubled 
with was diminished. It was a matter of some experiment to 
determine what proportion of vapor it was expedient to leave 
within the bulb, and one simple method which 1 adopted at that 
time suggested certain lines of research which I have been un- 
able to follow, and which I would like to mention here in the 
hope that some of you who are still in the incandescent lamp 
field can take it up. I had felt certain that there were two 
causes, as we all know, for the diminution in the candle power 
of the lamp. The first was the vaporization of the carbon, and 
its subsequent deposition upon the bulb reducing the transpar- 
ency of the same, and the second was the change in the condi- 
tion of the carbon filament itself. The vaporization, of course, 
is a function of the temperature to which the filament is sub- 




jected, and is to a very much less extent dependent upon the 
diflEerence of potential between the terminals. However, work- 
ing at higher potentials this difficulty increases. The other de- 
fect was due, as I said a moment ago, to the change in the struc- 
ture of the carbon itself. Apparently a deposit of carbon was 
formed upon one leg of the filament, whicn carbon was sepa- 
rated from the opposite leg. I was interested in ascertaining 
whether 1 could prevent this deposit, and so maintain the normal 
appearance of the filament by the interposition of a shield be- 
tween the two legs of the carbon. I supported a glass plate 
between the two legs of the carbon filament, and suspended the 
lamp vertically, the looji hanging down, and noted the deposition 

Fig. 4.— Mr. Colby's Experiment. 

of carbon upon this shield between the two legs of the filament. 
This, of course, would be expected. But a curious feature 
of it was this, that the deposit was principally on one side, 
and that the depth of deposit over this glass shield increased 
from the top of the shield down towards the bottom, that is, 
the loop of the lamp being in this form (a Fig. 4) and the shield 
being down here {b g\ the depth of the deposit was heaviest at 
the bottom instead of heaviest at the top wnere the greatest dif- 
ference of potential existed. Fig. 4 represents the general out- 
line of the lamp. It was known at that time as the Mogul lamp. 
A number of them were placed in the Equitable Building, 120 
Broadway, in 1883 and 1884, and attracted considerable atten- 
tion at that time on account of the large candle power of the 


lamps. They were made up to 600 candle power. The diffi- 
culty we had in the first construction of these lamps, was due to 
a discharge directly across from stub to stub. I then put here a 
glass plate {b c\ which was supported on a neutral wire at that 
point, to increase the distance between the terminals and prevent 
any direct path between the two. The deposit that was formed 
upon that plate I will illustrate by a line like that {J> d Fig. 4,) 
showing increase in thickness at the lower edge of the glass 
plate. Both legs of this filament under these conditions with 
the interposed shield, remained perfectly clear and as brilliant as 
they were in the original lamp, although with increase of tem- 
perature the deposit of carbon on the bulb was materially in- 
creased. I then sealed into another bulb, omitting the glass 
shield, a series of platinum wires going all around it, in the plane 
of the enclosed carbon, just little hooks, the wires passiuff 
through the bulb. I connected a telephone to the terminal 
which we will say was the positive pole and to loop No. 1, and 
with the lamp working at its normal candle power, after I had 
obtained a certain degree of exhaustion, I succeeded in getting a 
musical note in the telephone. By then transferring the conduc- 
tor to loop No. 2, I got a note of a slightly higher pitch, and 
upon transferring the connection to each succeeding loop the 
pitch of the note correspondingly increased until I reacted a 
point which was nearly diagor^atly opposite the stub + or in the 
line -|- 6, which would be the diagonal of the area enclosed by 
the loop, when I got the maximum note from the telephone. 

As I passed alone up here (7-10) the note diminished in pitch 
until I got up here (10) when it was inaudible entirel v. By con- 
necting the telepl)one to the negative terminal and the sealed-in 
wires, I got no sound whatever. It was always a mystery to me 
and it is not yet solved, for the reason that I have been out of 
the incandescent lamp business for several years, and I would 
like to know whether any one else can explain the matter. As 
I understood Prof. Anthony in his paper to-night, he stated that 
the action which produced the blackening was not purely elec- 
trical, but was in all probability simply the volatilization of the 
carbon alone at high temperatures. If a telephone was inserted 
between any two of these loops, 1 got no musical note whatever, 
indicating that there was no electrical action between those two 
points — no difference of potential sufficient to give a telephonic 
current. A peculiar feature about this experiment was this: that 
the lamp was on a direct current circuit, and the pulsation which 
would give that musical note must have been in all probability 
due to mequalities in the current of the dynamo. I used this 
dummy lamp as a means of indicating when I had secured the prop- 
er degree of rarefaction in the other lamps from the same pump. 
That is, this lamp was attached to the same fork by which other 
lamps were being exhausted, and the exhaustion was continued 



until I got a sHeht note in the telephone when 1 dibcontinued the 
exhaustion. These lamps, as they went out, had a residual at- 
mosphere of chlorine gas, and possibly some little undecomposed 
chloroform which was Subsequently decomposed in use. I made 
another preliminary experiment with a different construction 
which was known as the U tube lanip. I believe it was subse- 
quently patented by Mr. Stanley, in it I had a U loop of the 
same snape as shown in Fiff. 4.* The object of this construction 
was to protect each leg of the carbon filament from any direct 
electric action across from the other leg. This lamp was raised 
to a very high temperature without the filament changing its ap- 
pearance, although the blackening of the bulb was very pro- 
nounced. I am very glad that Mr. Howell has brought some 
samples of lamps here to-night showing the shadow cast by the 
carbon filament. I think any one who has had very much prac- 
tical experience in the manul^acture of lamps will be surprised to 
learn that carbon does not cast a shadow at all. It certainly 
was a very common thing in my experience to see lamps 
exhibiting this charactistic. I have succeeded in obtaining it 
with various lamps, and with platinum, iron and copper filaments, 
and I know no reason why, if the conditions are made proper, 
it may not be produced with all lamps. Of course if the carbon 
is raised to a comparatively low temperature, and not subjected 
to sudden changes, the volatilization will be very uniform and the 
shadow of the filaments will hardly be perceptible. Whereas if 
there are irregular or weak points in the filament or it is subject- 
ed to sudden changes in potential, then the shadows become 
quite marked. 

Dr. L. K. BoH^: — Volatilization is due to the mechanical 
action of the current. The theory advanced by the gentleman 
who spoke before me, was, to my knowledge, put forward first 
by Professor Crookes, of London, about 1880, in Nature, He 
explained that volatilization is due to that trace of oxygen still 
contained in that trace of air which cannot be removed by ex- 
haustion. This trace of oxygen is said to combine with a particle 
of carbon, forming carbon dioxid. The carbon dioxid is said to 
be decomposed on the inside glass walls, leaving the carbon on 
the inside surface of the glass; then the oxygen is said to return 
to act on a new particle of carbon, etc. This is certainly impos- 
sible, because there is no chemical power on the glass walls to 
decompose a chemical combination, and further, in the presence 
of such a great excess of carbon it is impossible to form carbon 
dioxid ; only the carbon monoxid can be formed. 

I accept the theory that chemical action takes place within the 
lamp chamber, and that some carbon monoxid is formed, but this 
gas will remain in the globe just as the rest of the residual gases 
remain there. 

I further wish to say something about fusing carbon. That 
carbon can be fused to a certain extent, everyone of you has 


seen, and I am surprised that this has not been mentioned here 
to-night. I refer to the treating of carbon filaments. In treat- 
ing the filament, the hydro-carbon in the treating apparatus is de- 
composed by the electric current, and we have then what the 
chemists term carbon in statu nascendi that is, the moment 
in which it is set at liberty, in which it is born ; and in this 
moment it is more readily capable of entering into combination 
with any substance it combines with, or with other carbon atoms, 
forming with them carbon molecules. So we have there, practi- 
cally speaking, atomistic carbon, while otherwise, what we gener- 
ally see before us is molecular carbon. Of how many atoms the 
carbon molecule consists is not known. Some speculative scien- 
tists suppose, and I suppose with them, that the number of carbon 
atoms in the molecule produce the different forms of carbon with 
reference to their physical condition, that is amorphous carbon, 
^phite and diamond. If, while treating a filament this atom- 
istic carbon set at liberty from the decomposing hydro-carbon, 
combines with other atoms to form a molecule, it settles on the 
surface of the filament in that half fused condition referred to 
above. The steel-like appearance of a well treated filament is 
nothing more than a coating of fused carbon on a porous fila- 

Regarding pure carbon, I might just state that this deposit of 
carbon on the porous filament, that is, the steel-like looking car- 
bon is really pure carbon, the purest that can be produced. 

With reference to the bromine lamp a great many experiments 
have been described to-nijrht, but I want to ventilate for a 
moment the theory of that lamp. It is not disputed by anyone 
that the bromine lamps do not blacken, but how is it that these 
lamps remain practically clear while carbon lamps do blacken ? 
In one of Professor Anthony's tables, it is stated that a 
bromine lamp lost in one instance 3.1 candles. That means, as 
Mr. Howell explained, that the resistance of the filament in- 
creases in a bromine atmosphere as well as in a vacuum lamp. 
How do we account for that now ? Where does that carbon go 
to which is missing ? I do not believe that a mere molecular 
change in the structure of the filament causes the higher resis- 
tance. I believe that volatilization of the filament takes place in 
the bromine atmosphere. Where does the carbon go to since it 
is not found on the glass walls? It must be somewhere. In my 
opinion it combines chemically with the bromine, and such a 
combination does exist ; it is tetra-bromine of carbon. This sub- 
stance has not been produced out of the elements, bromine and 
carbon directly, but it can be produced with the ordinary facili- 
ties of chemical laboratories. Tetra-bromine of carbon is not 
black, and it may be in the lamp globes in infinitely small quan- 
tities, but enough may be in there to prevent the blackening. 
Combinations take place in the lamp chamber : for instance, the 
formation of carbon monoxid has not been disputed by the other 


gentlemen here, and has been held up by every one who talked 
about it to-night. So if one chemical combination takes place 
another one can take place. Although this substance (tetra- 
bromine of carbon) has not been prodnoed from the two ele- 
ments directly, it has been produced in chemical laboratories and 
may be prodnoed from the elements directly by the intense heat 
of the electric current. This will, in my opinion, reasonably ex- 
plain the freedom from blackening of the bromine lamp. 

I should like to say something now about carbon particles and 
carbon vapors or gaseous carbon in lamps ; volatilization of the 
filament takes pleSe, that is a pretty well settled question, but in 
what form is tne carbon present ? Is it in the form of vapor, 
that is, as gas. or in a tinefy divided condition, that is, as particles 
of carbon f If we consider that it is very hard to get carbon 
into the form of gaseous vapor, then it is easily understood that, 
even if we accept that carbon gases exist near the incandescent 
filament, -it must certainly condense like mercury vapor or any 
other volatilized liquid when it goes a little away from the heated 
filament, and then it will certainly fall as particles of carbon on 
the glass walls I want to be understood distinctly about this. 
If there is really carbon vapor, that is. carbon gas in the lamp, it 
can be there only in the closest neighborhood of the white glow- 
ing filament, and must certainly condense like everything else 
when further removed away into cooler portions oi the lamp 
chamber, and must settle on the glass walls as finely divided 
particles of carbon, as carbon dust, and not as gciseous vapor. 

Mr. Olan: — I am surprised to hear that dioxid ot carbon 
could not in first hand be formed from oxygen and cari>on, where 
there is an excess of carbon. That it ooes form is a fact on 
which the metallurgy of the iron is based. Dioxid of carbon is 
formed just before the blast. Later on, as this gas arises in the 
furnace, it is transformed by the carbon into monoxid of carbon 
and receives as such the reducing qualities which makes the iron 
from the ore. I do not think I liave heard that fact denied be- 

Dr. Otto A. Moses : — I have been very much edified listen- 
ing to the general discussion, both from a chemical and practi- 
cal standpoint. But in a matter of such importance as that, 
which seems to be generally recognized as fundamental, we ought 
to be very careful to consider all available theories of action, in 
order to be able to guide ourselves and others where vast sums of 
money have to be expended in the pursuit of some development 
of them. Many different views have been expressed, apparently 
discordant in cnaracter; and it seems to me that the time has 
about arrived, after fifteen years of experiments in the direction 
of incandescent lighting, for them all to be correlated so that the 
practicioner can take new points of departure in the future 
manufacture of the carbon incandescent lamp. It is a veir im- 
portant thing to suspend judgment during tlie progress of any 


invention or discovery until sufficient data have been collected, 
to enable us afterwards to formulate theories. The time, I 
think, has now arrived (and it may be of some interest for it 
now to be promulgated) for the advancement of one more theory 
which has not been referred to this evening, nor published, to 
my knowledge, although it was cast into shape some 14 years ago. 
The use of millions of incandescent lamps demonstrates the truth 
of the theory then propounded. The precedent is given to us 
by Faraday, when he said that the thing of all things that he 
admired most in a man was his power to suspend judgment, and 
he added, it was due to this power that Ampere had himself lost 
the opportunity of predicting phenomena which have since 
rendered Faraday's name immortal. When Ampere first noticed 
the retardation of the movement of the magnetic needle above 
a revolving disk of copper he could give no substantial reason 
for it, and, therefore, ne suspended his judgment of the facts. 
Experiments in the hands of Faraday afterwards developed the 
full value of this obsei^vation. 

When the first hundred incandescent lamps were made and 
shown at Menlo Park, the world had become very much excited 
over the subject we are now discussing. The lamps liveld but 
from 50 to 100 hours each. Very few exceeded 100 hours. The 
globes became densely coated with a black deposit, and altogether 
the expectations of those who had devoted their time to the sub- 
ject, were very much clouded from that ominous fact. Professor 
Crookes was inclined to believe that no carbon filament could 
last long in a residual oxygen vacuum, and in his argument re- 
vived an idea that had developed in the hands oi St. Claire 
Deville about the dissociation of carbonic acid in high tempera- 
tures, and the subsequent deposition of carbon at lower tem- 
peratiires; and many scientists were then inclined to believe 
that this act of dissociation would finally and inevitably lead to 
the disintegration and rapid destruction of the filament. Just at 
that time the problem of determining what was the chemical 
composition of that coating was placed in my liands bv Mr. Edi- 
son and was investigated for several months. Those hundred or 
more lamps were submitted to all kinds of tests and analysis to 
discover what that coating was, and I am glad to say that it was 
possible to determine beyond all doubt that it was not, as was 
surmised by Professor Crookes, a deposition of pure carbon, but 
a hydrocarbon and a paraffin. In the beff inning it was thought 
to be the body of the filament, itself disintegrated, projected 
electrically upon the inner surface. But there w^ere some diffi- 
culties in the way of that hypothesis, and further analysis dem- 
onstrated that while approximating in composition to tlie 
filament, the substance was not identical with it. Some of the 
experiments have the very greatest bearing upon the subject 
discussed in Professor Anthony's valuable paper, because the 
gases chlorine, bromine and iodine were used for the purposes 


of attacking that inner coating in order to find out b^ substitn- 
tion what was tlie composition of the pellicle. It is interesting 
to recognize the fact tliat chlorine ana these other gases do not 
attack the body of the filament ; and by the change of color and 
the clarification of the pellicle from a dark substance into one 
quite translucent, and occasionally almost transparent, it was de- 
monstrated that this pellicle had been attacked by the chlorine, and 
that consequently it was not a pure carbon. Further experi- 
ments demonstrated also that in tlie pellicle there was hydrogen, 
carbon and some nitrogen. The pellicle was submitted to the 
action of chemically pure, dry chlorine gas. The formation of 
substitution compounos seemed to be almost instantaneous. The 
pellicle was attacked and became of a horny nature. The 
Tacuum globes had their ends broken oflf after insertion into 
vessels containing chlorine gas. They were partially buried in 
snow for several days, in order to see what effect would be pro- 
duced by the condensation of any liquids that might have been 
formed by the action of the chlorine on the pellicle. Where the 
heat was taken away at that particular point in contact with the 
snow, a concentration of action was observed to have taken 
place. These experiments, and quite a number of others with 
which I will not fatigue you, led to this conclusion in my mind, 
that the carbon filament is nothing but one of an infinite series 
of hydrocarbon compounds commencing with the most volatile 
liquids, or, perhaps, even with the gases, and extending up to 
the diamond. Tne hydrocarbon is invariably present. At about 
that time Professors i oung. Barker, Rowland and Brackett were 
at the laboratory, and some of the carbon filaments were sul)- 
jected to the most extraordinary temperatures for s[)ectroscopic 
analysis of their light. One, in particular, fused at its point of 
rupture. While it was being gradually heated, the spectrum was 
observed by Professor Young. The hydrogen line was invari- 
ably present in all, except at the poinf of rupture of this fila- 
ment, when it was thought to have disappeared several seconds 
before breaking. But up to that point there was no doubt in 
the minds of any one of the observers that hydrogen was pi'es- 
ent. That fact I shortly afterwards mentioned to M. Dumas, 
the permanent secretary of the French Academy, and the greatest 
authority at that time on carbon in the world, to whom was due 
the determination of the atomic weight of carbon. At that time 
I ventured to make the statement, that I did not believe there 
existed such a substance as pure carbon. lie 'said to me, " I am 
very much inclined to believe it, perhaps, with the exception of 
the diamond." In the manufacture of carbons for incandescent 
lamps, the increase of temperature commencing with the heating 
of tlie organic matter in a vacuum gradually, causes distillation 
of the volatile matters present, until vou get to the so-called car- 
bon skeleton. Submitting that finally to arreater and greater 
heats, you find invariably a shrinking of tfie carbon skeleton. 


That shrinking has no absohite limit. Towards the end of the 
carbonization, no we ver, when the temperatures are enormously 
increased, it is scarcely perceptible. The shrinking, between the 
temperature of the air and that linal tempei-ature at which car- 
bons are now produced, is about one-third in bulk. So that there 
we have evidence of a continuous distillation of volatile portions 
of the hydrocarbon filament, until the limit is reached by the 
disintegration or, perhaps, volatilization of the carbon. It one 
considers this phenomenon we have at once a solution of all 
these discordant phenomena reported during our present discusr 
sion. The known paraffins will distill oflE, together with the long 
series of them, more and more infusible in tlieir nature, and yet 
unknown and unstudied until finally a residual carbon (?) is left, 
which, as Professor Anthony has said, is in appearance, like the 
finest steel and is exceedingly hard. 

An analogy strikes me here which may be of service in con- 
sidering that question. We have all observed in the druggists' 
windows the volatilization of camphor at ordinary pressures, and 
we have also been inclined to believe that the deposition of the 
condensed vapor, formed towards the light, is connected in some 
way with the action of light, since it would seem that at the 
place where the light entered the vessel would be a greater tem- 
perature than elsewhere in the enclosing chamber. &it there is a 
time in the night when radiation takes place, if the vessel be op- 
posite to an open window, where the heat radiates from the vessel 
mto space, and there will be a deposition on the inner surface of 
the vessel in the direction of the window, which, during the day- 
time, was really the point of greatest heat. In some such way 
we may suppose that the paramns and all that series of hydrocar- 
bons that are more fusible than the residual hydrocarbon left in 
the filament while it incandesces, would precipitate upon the 
colder surface of the chamber. That is made evident, too, by a 
study of the phantom shadows cast. This deposition of carbon is 
but a process of simple distillation continuously taking place. Why 
should it not take place at once on the first ignition, is a natural 
inquiry. Because the particles have been rendered semi-plastic, 
and have been fused throughout the mass of the hydrocarbon, 
and a rupture must take place in the ^ occluding cells before the 
enclosed hydrocarbon, of lower melting point than the filament, 
can escape. Even if the temperature is kept constant in the 
filament, the wearing away still continues. There is a constant 
evaporation taking place and a deposition upon the colder sur- 
face of the globe. 

It may be asked why these observations have not before been 

a'ven to the world. They were formulated and submitted to 
r. Edison at a time when they became practically valuable, 
for only when the cause of this blackening was known did the 
future of the incandescent lamp become assured. It simply be- 
came necessary to increase the temperatures at which the fila- 
ments were carbonized to the very highest point possible, in 



order to prolong the life of the lamp. That method wa« 
adopted, and it wae not generally known outside of that labora- 
tory. But it was the turning pomt in the commercial production 
of the incandescent lamp. When, on discovering this fact, it 
was referred to Mr. Edison as of sufficient interest to be pub- 
lished to the world, he made one of his characteristic remarks. 
He said ; " We are on a forced march and we haven't time to 
bury our enemies, or to put up tombstones over them." 

The Chaikman : — If there is no further discussion of the sub- 
ject, we will ask Prof. Anthony to reply to what has been said. 

Prof. Anthony :— Mr. President, at this late hour I will touch 
upon a few points only of those brought out in this discussion. 
With reference to Professor Elihu Thomson's remarks upon the 
softening of carbon, 1 did not wish to be understood as endors- 
ing the statement that it could not be softened. The supposed 
fact had been adduced as an argument against its vaporization, 
and I pointed out that even if it were true that melting, or soft- 
ening never occurred, it was not a valid argument. A little 
further on I referred to the fact that Depretz had succeeded in 
softening, and even welding, rods of carbon more than fifty 
years ago. 

With reference to the remarks of Mr. Howell, when I went 
to the Mather company, six years ago, I had considerable to do 
with incandescent lamp manufacture, and had observed that 
lamps sometimes improved in candle power for the first 50 hours 
or so, but this was generally, and my impression is, always, 
accompanied with decrease in resistance and consequent increase 
of current. It was not the usual result, and I always ascribed it 
to diflEerences in the filaments such as might occur from different 
temperatures in the carbonizing furnace, or even to the different 
positions of the filaments in the boxes in which they were packed 
for carbonization. Table III. shows an increase in current and, 
therefore, decrease in resistance in both vacuum and bromine 
lamps at 210 hours, and yet the vacuum lamps had fallen in 
candle power. 

Mr. Howell states that these lamps are poor vacuum lamps, 
and exhibits the results of tests that show a remarkable life and 
remarkable uniformity in candle power and efficiency. I can 
only say that I have never met with such lamps in commercial 
use, and remember well that when I was obliged to use Edison 
lamps in my own house because of the injunction restraining 
the Mather company from using others, 1 found the failure in 
candle power very serious. If the lamps of Table III. dive poor 
lamps, tney were aU alike up to the point of exhausting, and the 
tests show a remarkable difference in behavior. As to the use of 
55-volt lamps for these tests, as I understand 55-volt lamps 
formed a considerable portion of the product of the Waring 
factory and of the Perkins factory before it. 1 understood that 
they found there was less to fear from competition in lamps of 


this voltage than in those of 100 volts or above. In other words, 
50-volt lamps on the market were less satisfactory than those of 
the hisrh voltages. I hardly see how this agrees with the state- 
ment that any one can make 60-volt lamps. 

A.S to the variation in voltage in the individual lamps of Table 
III. they were taken from lamps all made at the same time from 
the same '* batch'' of carbons, in order to remove any question as 
to the cause of the differences which it was expected would de- 
velop in the final test. They could not be volted until they 
were finished, and they then had to be taken as they came. 
Whatever difference there was in individual lamps, it was greater 
for the bromine than for the vacuum lamps. The bromine lamps 
were started also at a slightly higher eflBciency, fo that every 
advantage was given to the vacuum lamps. 1 fail to see how 
these differences in conditions affect the comparison between 
the two. 

I wish to add that my object in presenting this paper was to 
point out the theory as a matter of scientific as well as pra<;tical 
importance. I am glad to find among those best qualified to 
judge, that the vaporization of the carbon is generally accepted 
as the cause of the blackening, but I had not found such general 
acquiescence before, and in the argument for the Edison com- 
pany in the suit to which Mr. Howell has referred, it was pro- 
nounced absurd. As pointed out by Professor Robb, the rapid 
increase in the blackening due to small increase in the voltage at 
which a lamp is run, shows the vaporization to be due to neat 
rather than to electrical action, it is what we should expect 
from the rapid increase in the vapor tension with rise of tem- 

Sjrature that occurs in other cases. I cannot agree with Dr. 
ohm and Professor Elihu Thomson, that the vapor would con- 
dense as soon as it left the region of the filament This might 
be true if a gas were present to which it could give up its heat, 
but if the vacuum were perfect except the carbon vapor, to what 
would it give up its heat except to the walls of the vessel ? With 
reference to the claim of another speaker, that gases in the cham- 
ber may serve as the carriers, I would call attention to the fact, 
that the presence of any gas in the chamber, in proper quantity, 
retards the blackening. There are other points I should like to 
touch upon, but considering the lateness of the hour will leave 
the matter here. 

Mr. Howell : — In regard to Professor Anthony's experience 
with Edison lamps I have no doubt he is entirely right. You 
cannot expect results like those I have shown, from anything but 
the type of lamp upon which this test was made. If Professor 
Anthony has burned in his house 115-volt lamps they will not 
give any such results, and if I were to come here and show you 
these curves, and say they are characteristic curves of Edison 
lamps I would be deceiving you. I have shown you that curve 
because it is made by lamps of the same type as those tested by 


Professor Anthony, and gnoted in hid paper. If he had pro- 
duced another type 1 would not have exhibited those curves at 
all. I would have shown the same thing that he showed. 

[President Houston here resumed the chair.] 

The President: — Before going any further the Institute 
may like to know that I have had the pleasure of sending the 
following message to Chicago : 

"As President of the American Institlte of Electrical 
" Engineers I desire to send hearty congratulations on the sue- 
" cess of our first dual meeting. It gives me great pleasure to 
" address at once two meetings, over 1,000 miles apart, and to 
*• know that that has been rendered possible by the advances in 
" that branch of engineering which it is the privilege of our 
" society to represent. 

" The Institute has agreed, provisionally, to adopt the name 
" ' gauss,' ' weber,' ' oersted,' and 'gilbert ' for the magnetic units 
" 01 flux density, magnetic flux, magnetomotive force and le- 
" luctance." 

I sent them word that Professor Anthony's paper Lad been 
read and listened to with great attention, and was now going into 
debate. The Cliicago meeting sends word : 

*' The Chicago meeting sends congratulations to the New York 
" meeting, and trusts that the intercommunication thus, for the 
" first time, inaugurated by means of the telephone will not be 
" the last. It believes that considerable advance will be made 
'• in electrical science by the idea of holding simultaneous meet- 
" ings in different parts of the country. It also sends word that 
" Professor Anthony's paper has been read and is now being 
" discussed." 

If there is no other gentleman who desires to discuss Pro- 
fessor Anthony's paper, i would like to make one or two brief 
remarks. I woula like to discuss this paper at great length, but 
time does not permit. 

At the time the Sawyer-Man lamp came out, it was my pleas- 
ure to make some investigation and experiments in lamps con- 
taining very low vacua. The Sawyer-Man tvpe of lamp was a 
lamp with a fibrous carbon filament in whicn instead of the or- 
dinary vacuum produced by a pump, an attempt was made to 
produce a vacuum, and I believe a fairly good vacuum was made 
by rarefying a gas, heating it to high temperature and sending a 
current of nitrogen through it, and some very fair results were 

While I do not wish to criticise Prof. Anthony's paper, since I 
know that the term that he uses is a term that is commonly em- 
ployed, still I think the term is a bad one, namely " eflSciencies 
in watts per candle." This would make the efficiency equal the 
watts divided by the candles, or the activity divided by the lumi- 
nous energy. Now if we consider the electric lamp as a device 
for converting electrical into luminous energy, as it of course 


is, then this expression would necessarily be faulty, since it 
would show a hi«rlier eflBciency, the poorer the lamp is as a trans- 
lating device. Of course the phrase should be " candles per 
watt." It should be '* eflSciency equals candles divided by 
watts :" or the luminous energy divided hj the activity. This, 
however, would not be strictly accurate in itself, since the lumi- 
nous energy would require for actual practice to be multiplied by a 
physical constant ; that is multiplied by a constant, varying 
with the distribution of the wave lengths m the different parts or 
the spectrum. I would propose for use in this connection, if in- 
deed it has not been used, the term " candles per kilowatt," thus 
making the efficiency equal to the luminous energy divided by 
the total energy. 

Pbof. Anthony ; — I perfectly understand that criticism, and 
agree with the Chairman entirely. I was simply using the term 
as it is generally used. [Adjourned.] 

[Owing to lack of time the following remarks by Mr. Moore 
were submitted after adjournment.] 

Mr. D. McFarlan Moorb: — Mr. President, the statement 
that the most important problem in connection with electric 
lighting to-day, is the successful production of a more efficient 
lamp, I do not think will be questioned. Our present knowl- 
edge seems to indicate that we nave about reached the limit of 
efficiency in dynamo construction, and that by far the most in- 
efficient portion of an electric lighting installation is that where 
the current is transformed into li^ht, viz., the lamp. The sub- 
ject under discussion to-night is primarily the blackening of lamp 
bulbs and the consequent decrease in efficiency. The blackening 
material is the disintegration of the filament, that is, the blacken- 
ing is caused by the volatility of the carbon. Therefore, the 
apparent remedy is to get a filament that will not disintegrate 
and volatilize, and at the same time have high efficiency and 
long life, or better still get rid of the filament entirely. This 
would bean "ideal" lamp, although the ideal filament lamp de- 
scribed by Professor Anthony is by no means an impossibility. 
It is not difficult to conceive of a filament so constructed that it 
will rupture the moment a certain degree of disintegration (it 
may be very small) has been reached. A filament with a very 
hard and smooth surface, yet soft interior, might accomplish this 
purpose. That is, the filament t© be so designed that it shall have 
but little life after its glaze has been punctured or destroyed due 
to the combined action of heat and electrical action, but not by 
'^air washing." 

Heat means molecular action, which, if sufficiently violent, par- 
tially overcomes cohesion, and the molecular action is then in 
accordance with Newton's first law. Since this process is con- 
tinuous and in one direction, that is, from the filament, there is 
little liability of particles, after having once escaped from the 
cohesive forces, oi returning to their original positions in which 
they constituted the filament. 


The paper attributes the so-called " phosphorescent" light 
(which, by the way, seems to be a very misleading and poorly 
adapted name for this phenomenon) to the molecular impacts upon 
the enclosing chamber, but the study of the results obtained with 
different degrees of vacuum would seem to indicate that the 
most light is produced, when the enclosed gas is attenuated to a 
degree most suited to be thrown into a state of high vibration 
by the electric impulses of the current. It is also stated in the 
paper that a great potential difference is necessary to produce 
this effect, but it does not follow that a high tension current is 

I respectfully refer you to my paper before this body on 
September 20th last,' wherein I suggest the construction of a lamp 
without a filament, the light being produced by molecular dis- 
turbance due to rapid, successive, conductive discharges of a low 
potential current, which are, of course, oscillatory in character ; 
and, on account of self-induction, produce the high tension neces- 
sary to molecular vibrations of sufficient frequency to cause 
luminosity in the surrounding space, filled with the proper 
quantity of vapor or gas, and a vapor or gas best adapted to the 
purpose, viz., that of producing light. 

The lamp of to-day cannot withstand the demand of these 
progressive times much longer, and a new method of electric 
illumination must shortly succeed it. The lamp of to-day may 
evolve into either a straight continuous light-giving tube of any 
length, or evacuated space in every conceivable form, depena- 
ing upon the principle that luminous molecular vibrations gener- 
ated in one portion of an evacuated space (best concealed) will 
travel throughout the confines of such space. It is upon these 

feneral lines that the electric lighting of the future will proba- 
ly be carried out. 

[Communicated after adjournment, by Prof. Keginald A. 


Professor Anthony's paper deals with a subject of great im- 
portance from a practical standpoint. As 1 understand him, he 
considers that tlie blackening of incandescent lamps is due 
mainly, if not entirely, to a thermal vaporization of the carbon, 
as distinguished from the vaporization produced by electrical 
means. This conclusion can hardly be accepted by*^ those who 
have done much experimenting on the subject. 

To mention one single experiment (due originally to Mr. 
Edison, I believe,) w^hich will be a familiar one to most lamp 
manufacturers. If we take a small bundle of glass fibres, clean 
them carefully, then spread them out like a broom, and seal them 
in an incandescent lamp, so that the plane of the broom is per- 
pendicular to the plane in which the filament is, and lies between 

1 Tbanbactionb, vol. X., p. 437. 

1894.] DIS0US8I0N IN NEW YORK. 179 

the legs of the filament, we shall find, on running the lamp at 
its normal voltage for a few hundred hours, most decided evid- 
ences of Crookes' effect. For it will then be noticed that, while 
the side of the broom next the + terminal is perfectly clean, go 
far as the eye can tell, the side next the — terminal is covered 
with a thick, black deposit of carbon. 

This experiment would appear to be conclusive, for if the 
carbon deposit were due to vaporization by heat, both sides 
would be blackened, whereas one is perfectly clean, and the 
other is coated. 

Other experiments might be mentioned, but this will sufSce. 

It is also stated that the carbon deposit never appears as a line 
deposit. This is not quite correct, for though it is rare, I have 
seen it on more than one occasion, and so most probably have 
others. I conceive that the reason why it is so rare, is that the 
two legs of a carbon filament very rarely lie throughout their 
whole length in the one plane, and unless this be the case, a line 
deposit is, of course, an impossibility. 

I would also say that the carbon deposit is not evenly deposited, 
though it may be so in certain cases. I have seen ouite a number 
of lamps in which the deposit was in segments, Hkc those of a 
football, but with the spaces corresponding to the seams much 
wider in proportion, also lamps in which there were bare spots 
symmetrically arranged in the centres of dark deposits. Some 
circumstances led me to think that these latter were caused by 
the presence of conducting impurities in the glass, and I endeav- 
ored to reproduce them in predetermined forms, but failed, the 
theory being probably wrong. 

In the writer's opinion, the phenomenon is a true Orookes 
effect, and the decrease of blackening is due simply to the fact 
that it takes a greater potential to start a negative discharge into 
one gas from an electrode than into another gas. For instance, 
it takes twice the potential to create a negative discharge from 
an iron electrode into nitrogen, that it does to create a discharge 
from the same electrode into air. Some facts in thermo-chemis- 
try seem to throw a light on the subject, but at present there is 
not sufficient datum to prove the connection. It may, however, 
be mentioned, that if it is correct, phosphorous should act even 
better than chlorine or nitrogen, provided its vapor tension were 
high enough. 

[Communicated after adjournment, by Charles J. Eeed.] 

Professor Anthony quotes Fleming and Proctor as authority 
for the statement that the filament never casts a shadow in a 
carbon deposit. I have frequently seen the shadow in a carbon 
deposit in large lamps having a long but rigid filament. A very 
remarkable and unmistakable case I remember in 1887, was an 
Edison 100-candle 100-volt lamp at Idaho Springs, Colorado. 
The lamp gave a very bright light, being evidently "vol ted" 


too high. After burning about a month the filament ruptured 
about an inch from the base. There was no trace of copper in 
the deposit, though the filament was attached by copper plating. 
The green color by transmitted, and the red color by reflected 
light, were both entirely absent, but the globe was intensely 
blackened by a carbon deposit everywhere except in the plane of 
the filament, which showed a very strong and sharply defined 
shadow. The shadow was very deep on the side oi the globe 
farthest from the rupture, while it was nearly obliterated on 
the side nearest the rupture where the "blackening was most in- 
tense. This showed : 

(1.) That the shadow had been partly formed before the rup- 

(2.) That it had been mostly formed while the arc lasted at the 
time of rupture. 

(3.) That it was formed by particles of carbon moving in 
straight lines, and not by particles of copper. 

In regard to the evaporation of metals in vacuo mentioned 
by Professor Anthony, I have found that silver evaporates with- 
out the use of an induction spark at a temperature far below its 
melting point. If the carbon filament of a lamp be attached to 
platinum wires by a globule of pure silver, a bright mirror of 
silver (blue by transmitted light) will be rapidly deposited on 
the glass at the nearest point, even when large beads of glass are 
melted onto the wire close to the joint to keep it cool. 

Meeting of Western Members at Chicago. 

A meeting of the western members of the Institute was held 
simultaneously with the New York meeting, in the lecture room 
of Professor Stine, at the Armour Institute. At this meeting 
the paper of Professor Anthony was read, upon the invitation 
of the author, by Prof. Dugald C. Jackson, of Madison, Wis- 
consin. Through the kindness of Mr. A. S. Hibbard, the 
General Manager of the Chicago Telephone Company, the meet- 
ing rooms were placed in telepnonic connection with the Insti- 
tute rooms in New York City, and before the meeting of the 
Chicago members was called to order, a half hour or more was 
very pleasantly spent in conversation between members present 
at the Chicago and New York meetings. The possibility of 
bringing distant audiences in touch with the author of a paper, 
was satisfactorily established, and before adjournment, President 
Houston, at New York, spoke over the wire to attentive listeners 
in both cities, extending congratulations upon the success of the 
dual meeting, and informing the Chicago members that the re- 
port of the Committee on [Jnits and Standards had been ap- 
proved . 

The Chicago meeting was called to order with about 45 mem- 
bers and guests present, by the Local Honorary Secretary, who 


read the Institute rule under which the meeting was held. It 
was stated that 20 members, the requisite number, had signed a 
petition, and that in accordance witli the action of the Council, 
the Secretary had issued the call for the holding of this meeting 
in Chicago. Upon motion of Mr. B. J. Arnold, Mr. A. S. 
Hibbard was named as Chairman. Mr. Hibbard at once took 
the chair, and the Secretary read the following communication : 


Chicago, lUs., March 21st, 1894. 
Edward Caldwell, Esq., 

Local Honorary^ Secretary, American Institute of Elec. Engrs., 
1432 Monadnock Block, Chicago. 
Dear Sir: The use of the Long Distance telephone lines between Chicago 
and New York has been extended to the Institute for this evening by the 
Vice-President and General Manager, Mr. Edward J. Hall, of New York. 
Telephones have been placed in an adjacent room, and may be used by the 
members present in Chicago in communicating with members who are pres- 
ent at the New York meeting. 

Yours truly, 

A. S. Hibbard, 

General Manager. 

The Chairman then called upon Professor Jackeon, who read 
the paper as announced. 

Discussion at Chicago. 

The discussion was opened bj' Mr. Francis E. Jackson, of 
Harrison, N. J., who exhibited the diagrams, Figs. 1, 2 and 3, 
and who also presented similar arguments, and called attention 
to the points alluded to by Mr. John W. Howell at the New 
York meeting. [See p. 155 ante,^ He was followed by Professor 
Stine, as follows : 

Prof. Wilbur M. Stine: — The paper we have just listened to 
deals primarily with the '* age coating " within the bulb of an 
incandescent lamp; it argues that this is due to simple rolatiliza- 
tion of the carbon iilament, and that the presence of certain 
heavy gases in the chamber more or less prevents the formation 
of the coating. While some points have been overlooked and 
others but scantily noticed, the paper as a whole is broad and 
suggestive in its treatment of the physical causes involved in the 
blackening of lamp bulbs. Much has been written on this sub- 
ject, but writers have usually been too one sided in the data and 
explanations which they have presented. It is only when the 
work of many experimenters and authors is compared, that har- 
mony is established and the true explanation becomes apparent. 

The supposition, I had almost said belief, that mercurial va- 
por, supposed to be present in the lamp, was, somehow, the 
agency by which the black deposit formed, is so thoroughly 
explained away that it ought not again to be advanced. It has 
always seemed strange that so many writers caught at this straw 


for an explanation. I do not recall having seen any ^ood reason 
advanced a£ to why it should form the coating ana it i% rather 
singular that the suggestion ever gained headway. However, E. 
E. Oary, for example, in an article in the Electncal Engineer^ 
seems satistied that the blackening is due to remanent mercurial 
vapor. As usual, he attempts no explanation and even his experi- 
ments are open to criticism and further demonstltition . He fur- 
ther states, what is generally accepted, that the rate of blackening 
in mercurially exhausted lamps ( equally true for all types of 
vacuum lamps) varies with the density, elasticity, and lack of 
uniformity in filaments. 

A careful summary of experiments bearing on the production 
of the black coating, together with certain well known facts in 
the life history of the incandescent lamp, entirely supports Pro- 
fessor Anthony's statements. I will now attempt to summarize 
such experiments and discuss their bearing in order. In an 
article by Professor Nichols we find : 
( a ) That the rate of deposit is greatest in the early life of the 

( i) The distribution of the coating within the bulb is uniform. 
\o) No marked diflference in the blackening exists between 

treated and untreated filaments. 
(//) Lamps increase steadily in resistance as they grow older by 
use. Again from an article by L. S. Powell m the London 
E'eetrtcal lieview. 
{e) That carbons baked or flashed at a low temperature black- 
en the bulb more than those finished at a high temperature. 
That the film is a good conductor of electricity. 
Tf we discard hydrocarbon theories as not sufficiently proven, 
the initial rapidity of deposition seems due to the lees dense por- 
tions of the carbon volatilizing early in use, the rate then is also 
decreased by the lower temperature due to decreasing current. 

That the coating is uniform, supports the gaseous carbon view, 
since either by diffusion or convection currents, the carbon would 
be evenly distributed over the entire interior of the bulb. 

The fact that no marked difference exists in the blackening, 
whether the filament be treated or not, scarcely warrants mucn 
confidence being placed in the view that carbon is deposited by 
the formation and dissociation of some hydrocarbons. 

It is a well known fact that the resistance of the filament 
steadily increases with use. The deposited carbon must, in the 
nature of tlie case, come from the filament and nowhere else, thus 
constantly attenuating it. But why may not the successive 
heating and cooling of the filament cause it to l)ecome somewhat 
crystalline and graphitic, and add to its resistance and liabil- 
ity to break-down i 

Various conductivity and other tests, seem to prove conclusive- 
ly that the deposit is pure carbon, but a peculiar metallic looking 
nlm which is sometimes found spread over the filament has been 


1894.] DI8CUS8I0N IN CHIGAQO. 188 

by some considered to be due to an alloy of carbon and lead, the 
lead coming from the glass of the bulb. It has not yet been 
proven that such an alloy is possible under the conditions present, 
and the layer may be only graphitic carbon mistaken for a metal. 
And again, if carbon baked or flashed at a lower temperature 
shows more marked deposits, is it not due to less density of 
structure, giving rise to greater ease of volatilization ? The evi- 
dence in favor of the blackening being due to simply volatilization 
seems quite conclusive. It is sustained by what physics teaches 
us of the behavior of carbon at high temperatures. When heated 
in a vacuum it does not soften, because like NH4 CI it passes 
at once into the state of vapor, but, if a gas imder considerable 
pressure be present to prevent the flying off of its molecules, 
carbon softens and becomes waxy. 

Horizontal filaments do bend progressively, often touching and 
breaking the glass, and if a filament so softens and becomes like 
sealing wax, a liquid of great viscosity, there are good grounds 
for believing that it also slowly vaporizes. Professor Anthony 
proves very conclusively that the presence of remanent air or a heavy 
gas prevents the blackening; but he attributes its action wholly 
to convection currents. It this were the case, the distribution of 
the deposited layer would not be uniform, for it is the nature of 
such currents to rise. The deposition would then be greater on 
those portions of the bulb first impinged upon, since the gas leav- 
ing the filament would be more richly charged with carbon vapor. 

The uniformity of the deposit is so general, that we cannot 
assign the principal cause to these convection currents. Undoubt- 
edly convection currents do exist, but they are a minor cause of the 
deposit, and it seems entirely reasonable to suppose that diffusion, 
pure and simple, of carbon vapor, through the enclosed gas, is 
the leading factor. This diffusion, in lamps having a high vacu- 
um, mav become, to a great extent, a Crooices action. In such 
lamps the production of a " shadow " shows that the freed carbon 
molecules are not often deflected from a straight course. But 
such shadows are more pronounced in the neck than in the bulb 
of the lamp. In the neck the Crookes effect does occur, but in 
the bulb it is modified into diffusion. 

The distincti(»n between diffusion and the Crookes effect is 
simply the presence in the one case of deflecting and impeding 

In the type of lamps in which certain gases are purposely 
present, it would seem that diffusion chiefly, and convection cur- 
rents to a less extent, were the means by which the carbon reaches 
the bulb. This view weakens the convection-current explanation 
of the permanence of the filament of the bromine lamps. 

An im portant action of these heavy vapors has been entirely over- 
looked. The molecular weight of the carbon atoms is but 12 
against that of bromine, which is 80. When a carbon molecule, 
charged to incandescence with heat energy, comes in contact 


with the colder and heavier bromine molecules it is so greatly 
cooled by the interchange of energies that it can no longer exist 
in the state of a vapor, out is ledeposited as a solid on the fila- 
ment. The heatea bromine molecules rapidly dissipate their 
increased energy and return cooled for a fresh impact. This 
view is supported by the fact that carbon volatilizes in a vacuum, 
but, when under gas pressure, simply softens. This type of lamp 
is capable of much improvement, for but little, comparatively, 
has been done in this direction. The tendency would be to search 
for the heaviest possible transparent gas, not decomposed by high 
temperature, and to use it under relatively high pressure. It 
would be queer indeed to see incandescent lamps pass from the 
vacuum type to the other extreme of high pressure of a contained 
inert gas. Further, the contained gas should be without effect 
on the filament. That the iilament in the bromine lamps is short 
lived seems to indicate a chemical combination with the carbon 
at a high temperatures. 

Further discussion was carried on by B. J. Arnold, Ludwig 
Gutmann, Mr. Kammer, and others. 

Professor Jackson then answered a number of questions, and 
closed the discussion on behalf of the author, with the follow- 
ing remarks : 

Prof. Duoald C. Jackson : — We have here a remarkable paper 
with which to inaugurate the meetings of this section of the Insti- 
tute, and I am most happy to have been designated by Professor 
Anthony as his representative, and to have received your invita- 
tion to read the paper before you. The conclusions of this paper 
clear up in a straight-forward scientific manner several of the 
mysteries of the incandescent lamp. Some of the conclusions 
may not be fully borne out, hut the discussion shows them to be 
correct in the main. 

There are a few points in the discussion of Mr. F. E. Jackson 
(the other Mr. Jackson) which deserve much fuller consideration 
than we can give them at this late hour. Mr. Jackson has shown 
us some life and efficiency curves of Edison lamps which evidence 
the wonderful perfection of the incandescent lamp filaments now 
manufactured by the General Electric ('o. I think we owe Mr. 
Jackson our most cordial thanks for traveling all the way from 
Harrison, N. J., to Chicago to show us the curves. The evidence 
presented, however, does not prove that these filaments give as 
good results in vacuum lamps as might be obtained from them 
in bromine gas lamps. The curves which Mr. Jackson presents 
as representing Novak lamps no doubt correctly re|Mesent the 
lamps tested, but my ol>servation shows that there is likely to be 
considerable irregularity in the lamps produced in the small- 
er factories. This is a result which may be expected, on account 
of the refinement required in the manufacture of filaments. My 
observation shows that the gas lamps ( Novak lamps), in the main, 


retain their brilliancy throughout their life more satisfactorily 
than do vacuum lamps on the same circuits. On the other hand 
a few of the Novas lamps perform more poorly than their 
vacuum brethren. 

There is indeed a weakness in Table III, as pointed out, but 
eliminating that weakness does not, I think, vitiate Professor 
Anthony's conclusions. Neither does the fact that a carbon 
shadow is sometimes found. The shadow is sometimes very well 
marked in the carbon coating. This simply shows that the carbon 
molecules which leave one leg of the filament and are deposited on 
the opposite side of the bulb, do not come into collision with other 
molecules sufficiently often to be swerved materially from straight 
paths. The part of tlie bulb which is in the plane of the filament 
18 therefore partially shaded from the " molecular shower " by 
the filament itself. Upon the explanation offered in the paper, 
the shadow in the carbon deposit can only occur in lamps with a 
very high vacuum, which agrees with the statement made by 
Mr. F. E. Jackson. The argument that the carbon deposit is 
made by molecular deposition is strengthened by the fact that 
the deposit cannot be analyzed under a very powerful micro- 
scope. That is, the deposit seems to be perfectly smooth or homo- 
geneous when viewed under the microscope. 

At the close of the discussion of the paper, a vote of thanks 
was tendered to Mr. Hibbard, as the representative of the Chi- 
cago Telephone Company, and to Mr. Hall, as the representative 
of the American Telephone and Telegraph Company, for the 
use of the telephone lines, and also to l^rofessor D. C. Jackson 
and to Mr. F. E. Jackson for their interest in coming such long 
distances to attend the meeting. Professor Stine and the Armour 
Institute, which had placed such admirable facilities at the dispo- 
sition of the local meeting, also came in for a very hearty vote 
of thanks for their hospitality. 

It was stated by Professor Stine that the electrical and scien- 
tific journals containing the articles to which reference had been 
made by Professor Anthony in his paper, were upon the desk 
for consultation by any who wished to refer to them. 

Professor Stine, B. J. Arnold and Edward Caldwell were ap- 
pointed a committee to devise means to pay local expenses and 
to arrange from time to time for the holding of meetings. 

The meeting then adjourned. 


New York, April 18, 1894. 

Tlie eighty-sixth meeting of the Institute was held this date 
at 12 West 31st street, and was called to order at 8 p. m. by Pres- 
ident Houston. 

The Secretary read the minutes of the last meeting which were 

The Secretary read tlie following list of associate members 
elected and transferred at the Council meeting in the afternoon : 


Best, A. T. 

Carus-Wilson, Charles A 
CoLviN, Frank R., 
George, John C, 
Gerry, James H., 
Gladstone, James Wm., 
HoBART, Henry M. 
Hood, Ralph O., 
Hubbard, William C, 
Ingold, Eugene, 

Electrical Engineer, 

Hotel Ponce de Leon, 

St. Augustine, Fla. 
, Professor of Electrical Engineer- 
ing, McGill University, Mon- 
treal. P. Q. 
Treasurer and Business Manager, 
The Electrical Engineer^ 203 
Broadway, New York City. 
President, Raleigh Electric Street 
Railway Co., Marine Bank 
Bldg., Baltimore, Md 
Superintendent, The Self-Winding 
Clock Co., 163 Grand Ave. 

Endorsed by. 

W. G. Whitmore. 

Chas. D. Shain. 

Aug. NoU. 

T. C. Martin. 

Joseph Wetzler. 

L. Stieringer. 

James Hamblet. 

Geo. M. Phelps. 

A. £. Kennelly. 

Louis Duncan. 

Samuel Reber. 

S. W. Huff. 

Edward Durante 

James Hamblet. 

Geo. A. Hamilton. 
Manager, Edison Mfg. Co., West T A. Edison. 
Orange, N. J. A. E. Kennelly. 

Edwin J. Houston. 

Engineer, General Electric Co. , Ralph W. Pope. 

Schenectady, N. Y, F. W. Tischendocrfer. 

C. P. Steinmetz. 

Electrical Engineer with General A. E. Kennelly. 

Electric Co., 180 Summer St., Elihu Thomson. 

Boston, Mass. Caryl D. Haskins. 

Electrician, Royal Arc Electric Louis B. Marks. 

Co., 143 Liberty St., New York E. T. Birdsall. 

City. Chas. D. Shain. 

Consulting Engineer and Expert, T. C. Martin. 

Pittsburgh, Pa. A. L. Rohrcr. 

J. R. Lovejoy. 



Keeper, Edwin S., 
Macloskir, Chas. H., 
Neiler, Samuel G., 
Proctor, Thos. L., 
Searles, a. L., . 
Toerring, C. J., Jr., 
Wiley, Walter S., 
Total 17. 

Supt. of Electric Light Construc- 
tion, Western Electric Co., 22 
Thames St., New York City. J 

Engineer, with B. J. Arnold, 436 
The Rookery, Chicago. 111. 

Ass't. Electrical Engineer, The 

World's Columbian Exposition, 

4318 Berkley Ave.. Chicago, 111. 
General Manager, Riker Electric 

Motor Co , Newtown, L. I., 

N. Y. 
Engineering Dept., The Royal 

Arc Electric Co., 73 Watt St., 

New York City. 
Electrician, Royal Arc Electric 

Co., 143 Liberty St., New York 

Supt. South Omaha Electric 

Light Co., South Omaha, Neb. 

G. A. Hamilton. 

Ralph W. Pope. 

Stanford Brown. 

B. J. Arnold 

Fred. DeLand. 

Lemuel S. Boggs. 

R. H. Pierce. 

Lemuel S. Boggs. 

Fred. DeLand. 

Philip Mauro. 

Joseph Wetzler. 

Andrew L. Kiker. 

Chas. D. Shain. 

E. T. Birdsall. 

Louis B. Marks. 

Louis B. Marks. 

Franklin L. Pope. 

Edw. L. Nichols. 

W. F. White. 

Harris J. Ryan. 

• D. C. Jackson. 


Approved by Board of Examiners, December 7th, 1893. 

Greene, S. Dana Assistant General Manager, General Electric Co., 

Schenectady, N. Y. 
Eickemsyer, Rudolf President Eickemeyer and Osterheld Manufacturing 

Co., Yonkcrs, N. Y. 

Approved by Board of Examiners, March 20th, 1894. 

Morrow, John Thomas Supt. Electrolytic Plant, Boston and Montana Con- 
solidated Copper and Silver Mining Co., Great 
Falls, Mont. 

Johnston, A. Langstaff Consulting Engineer, Hestonville, Mantua and Fair- 
mount Passenger R. R. Co., 4300 Lancaster Ave., 
Philadelphia, Pa. 

Crandall, Joseph Edwin Electrician, C. & P. Telephone Co., 619 Fourteenth 

St., N. W. Washington, D. C. 

Total 5. 

The followins: applicatione for associate membersliip liave been 
received and will be acted upon at the meeting of Council, June 
20th, 1894. 

A. L. Croxton, San Francisco : L. 6. Lillev, Wyoming. 0.; Maurice Oudin, 
Sehenectadv ; Prank H. Knox, Baltimore ; f aiil A. N. Winand, Philadelphia; 
Frank W. ftrady, Wellsburg, W. Va.; Geo. IT. Harris, Birmingham, Ala.; 
Frederick L. Hutchinson, Elizabeth ; Edwin H. Bennett. Jr., Bayonne ; Her- 
bert Lloyd, Philadelphia; John E. Crigcral, Springfield, Mass.: Albert Scheible, 
Chicago; John B. Blood, Schenectady ; Arthur E. Childs, Philadelphia; 
George StepheDt?, Peterborough, Ont. ; Jas. P. Malia, Chicago ; H. C. Eddy, 
Chicago ; Philip G. Gossler, Brooklyn ; Wm. K. Archbold, Boston ; Jos. C. 
Mayrhofer, New York ; C. C, Chesney, Pittsfield, Mass. ; F. C. Caldwell, 
Columbus; Joel W. Stearns, Jr., Denver; George S. Bliss, Pittsburg. Total 24. 

Any objection to the election of these candidates should be 
tiled with the Secretary before that date. 


The President: — Have you anv otlier communication to 
make, Mr. Secretary t 

The Secretary : — I have the sad announcement to make, Mr. 
President, of the death of one of our esteemed members, Dr. 
Franz Schulze-Berge, wlio is well known to the profession, and 
who died on the 2l8t of March, in Brooklyn, N. Y. A suitable 
obituary notice has been handed in, and will be printed in the 
Transactions. * 

The President : — There is a communication here from the 
Committee on Tnits and Standards, which I will ask the Secre- 
tary to read. 

The Secretary : — This recommendation of the Committee 
on Units and Standards is based on a letter from T. C. Menden- 
hall, Superintendent United States (.oast and (xeodetic Survey, 
Washin^on, I). C, in which he requests the support of the 

New York, April 18th, 1894. 
To the Pi-esident and Council. 

Amekk AN Institute of Electrical Engineers. 

Gentlemen : — Your committee on Units and Standards X)^^ to recommend 
that a resolution be forwanled to Congress from the Institute urging the pas- 
sage of the bill legalizing the electrical units adopted by the Chicago Congress. 

F. B. Crocker, Geo. A. Hamilton, 

\V. D. Weaver, A. E. Kennelly, 

William E. Geyer. 

The President : — Geutlemen, you have heard the communi- 
cation from tlie (Committee on Units and Standards i What is 
your wish i What disposition of the case will you make ? Will 
you take action on it now 'i 

Mr. Townsend Wolcott : — I would like to ask about the 
question of jurisdiction — if that is a proper thing for our society 
to do. I think it is a very desirable thing to do, and if it is also 
proper I should be in favor of it. 

The President : — The Chair does not quite understand. 

Mr. Wolcott : — Are we authorized to do such a thing ( Is 
the American Institute of Electrical Engineers authorized 
to do such a thing i 

The President : — I suppose it is competent for the American 
Institute of Electrical Engineers to do wdiat they may see lit 
in the premises. Of course, all they could do would be to make 
a recommendation. 

Secretary Pope : — I think this communication from the 
chairman of the committee will thrown a little light on it. 

The President : — The Secretary will please read the letter 
directed by the committee to the President. 

The Secretary read the following letter : 

New York, April 18th, 1894. 
Professor Edwin J. Houston, 
Sir : — Our committee has signed the ap|)ended rough draft of a recommenda- 
tion to (\mncil. which can be considered at the next Council meeting. In the 


meantime, however, in case of ureency arising, we suggest that the sense of the 
meeting be taken informally. This might also serve as a notice that formal ac- 
tion will be taken at the next (annual) meeting of the Institute. 

Yours respectfully, 

A. E. Kenxelly. 

The President : — If Mr. Hamilton or Mr. Crocker, or any 
other member of the committee would like to say anything 
about this matter, the Chair would be pleased to extend the 
courtesy of the floor to them. 

Prof. Francis B. Crocker : — The desirability of doing some 
thing of this sort is unquestionable, I think. But as to its fonn- 
ality, possibly, some doubt might arise. Therefore, to avoid the 
latter question the committee suggests that the sense of the 
meeting be taken — to which, of course, there can be no objec- 
tion — ^and that formal action could be delayed until the next 
meeting of tlie Institute, which will be the annual meeting, and 
which would certainly be proper time to take formal action. 
This statement will also serve as a notice that such formal action 
will then be taken. In the meantime the bill might come up in 
Congress, and it would be well if the oflicers oi the Institute 
could use the fact that the sense of the meeting had been taken 
at a regular meeting. 

The President : — I see Mr. Hamilton and Professor Geyer ; 
do they wish to add anything to what Professor Crocker has 

Mr. George A. Hamilton : — I think what Professor Crocker 
has gaid covers the ground very thoroughly. 

The President : — Professor Geyer. 

Dr. William E. Geyer : — Of course, anything that we may 
do will not bind anybody, and as Professor Crocker has said, the 
idea is to find out whether the Institute would approve of such 

The President : — Does Mr. Weaver wish to add anything ? 
Does Mr. Kennelly ? 

Mr. a. E. Kennelly : — I have not anything to add to the re- 
marks made by Professor Crocker. 

The President : — Does any other member of the Institute 
wish to speak on this matter? If not, what action will the In- 
stitute take on the recommendation ? 

Prof. Crocker : — I move that it is the sense of this meeting 
that the passage of the bill legalizing the electrical units adopted 
at the Chicago Electrical Congress of 1893, be recommended. 

Mr. George M. Phelps : — Mr. Chairman, if you will permit 
me, I will suggest a slight addition, to make the action possibly 
stronger ; and that is, that this meeting recommend to the general 
and annual meeting of the Institute to be held hi May, a more 
formal endorsement and recommendation of the measure. I 
offer this because one or two speakers suggested that this meet- 
ing give its sense on this subject, and that Sie general meeting in 
May might take a more formal action. 


Prof. Crocker : — I accept that amendment. 

The President : — Gentlemen, it is moved and seconded, as 
you have heard. Are you ready for the question i 

[The motion was put and carried.] 

The President : — I take great pleasure now in introducing to 
you Mr. 1. H. Farnham, of Boston, who will read a paper on 
the Destructive Effect of Electrical Currents on Subterranean 
Metal Pipes. 

Mr. Farnham : — I have had the honor and pleasure of being 
a member of this society for some time, though have never at- 
tended but one of your meetings, so I feel almost like a stranger ; 
I hardly know what your customary methods are. Perhaps, as 
the paper is printed, a synopsis is all that you usually have 

S resented here. It has occurred to me that as we need the room 
arkened in order to see the lantern diagrams, which renders it 
impossible for you to read the paper as it is presented ; perhaps, 
it will be as well for me to keep pretty close to the printed 
paper, and this I will attempt to do. 

The subject before us jias frequently been discussed and some- 
times it has been very poorly presented. I will give you one 
example. There was a meeting of engineers in a city — no matter 
what city — a few months ago, and as this subject of electrolysis 
was to lie talked about I was invited to be present. A com- 
mittee was to report upon the matter. The committee had been 
in existence for a year, and the three members of it each 
made a separate report. The first one had found some gas 
pipes in months gone by, which he believed, had been destroyed 
by electrolysis, but of late he was not so sure about it. He 
thought that there might be some doubt as to whether electrol- 
sis was really doing any damage in that city. The next mem- 
ler of the committee related the fact, that in his city they had 
connected an incandescent lamp from the gas pipe to the water 

{ripe in a cellar, and tlie current which flowed there lighted the 
amp. The last one, whose remarks were really the most inter- 
esting, came forward with a specimen pipe in his hand and said, 
" I liave something to show you, electrolysis materialized." 
He knew it was a case of electrolysis, because he saw it take 
place. He said that a trolley wire broke, and it swish-swashed 
sometime through the air, and finally struck a gas post, and in 
striking the gas post it produced " tins hole in the pipe," which 
he showed. I don't know whether that is a sample of all these 
meetings and papers, but that is one at which I happened to be 
present. If, now, I am able to give you a little outline of the 
work we have accomplished in this field it may form a sufficient 
basis for your discussion. 

Mr. Farnham then read the following paper : 


A faptr prtsenttd at the Sbth Meeting of the 
American Inetitute of Electrical Engineers^ 
New York^ April t8th. President Houston in 
the Chair, ami at Chicago, April ^th, /<^, 
Lieut. Samuel Rodman, /r. in the Chair. 



For the past year or more, there have been read before water, gas 
and electrical engineering societies all over this country, papers 
on the subject of electrolytic corrosion of water pipes, gas pipes 
and lead cables. In fact, a meeting of such societies is incom- 
plete to-day without some discussion on this subject. It was, 
therefore, with hesitation and misgivings, that I considered the 
written invitation from the oflScers of the Institute, to prepare a 
paper on the " Electrolytic effect of currents on subterranean gas 
and water pipes." A prominent oflSeer of the Institute urged 
that as I was undoubtedly the first to discover and satisfactorily 
prove that this action was destroying cables, I ought to give the 
society an account of my investigations and the results. On this 
suggestion, the promise was made to lay before you such facts as 
opportunity would allow. If suflBcient data may be presented to 
form a nucleus for the evening's discussion, it will, I am sure, be 
of some practical value. 

Early in the summer of 1891, some lead-covered telephone 
cable removed from wooden ducts in Boston, showed very 
marked yet local spots of corrosion. The cause of the corrosion 
was generally attributed to acetic acid contained in the wooden 
conduit, which had, years before, caused corrosion on a few cables 
in certain sections of the city. In the case just mentioned, the 
corrosion was so severe, and located in spots only, that it led me 
to attribute the cause to electrolytic action from the railway cur- 
rents, and a letter was written to my company to that effect. 

A few months later, the lead covering of a cable, ( No. 208 ) 



resting upon the ground in manhole chamber No. 76, located at 
the comer of Berkeley and Newbury streets, was found eaten 
entirely through at the point of contact with the earth. I then 
felt certain the cable had been destroyed by the action of the cur- 
rent. With Mr. W. I. Towne, my assistant, I proceeded to 
prove the theory. 

We took measurements between the cable and the earth, the cable 
having been repaired and raised from the ground, and found 1.5 
to 2 volts diflferenceof potential, the cable being positive to the 

earth. A barrel of earth was procured from an excavation in the 
street, a metal plate placed beneath the earth in the barrel, and 
two short pieces of lead cable placed side by side on top of the 
earth. The plate in the bottom of the barrel was then connected 
to the negative side of a storage battery giving 4 volts potential, 
and one piece of the cable lying on the earth, was connected with 
the positive pole of the storage battery. The second piece of 
cable in the barrel was left without electrical connections. The 
earth was then saturated with water, and the circuit was closed, 
allowing the current to pass from battery to cable, to earth, to plate 
and to battery, for seven consecutive days. The pieces of cable were 




then examined, afid the piece which had been connected with the 
battery fonnd badly pitted, closely resembling the cable which 
had been destroyed, while the second piece of cable showed no 
corrosion whatever, proving conclusively that a current such as 
was found in the manhole, was sufficient to cause the damage 
that had been found, and that the corrosion was not, (in the case 
of the experiment at least), due to any acid or salts in the earth. 
Fig. 1 shows the barrel experiment, and Fig. 2 is a photo- 
graph of the cable No. 208, which has been described as found 
resting on the earth in the manhole chamber and corroded 
through ; also the pieces experimented upon in the barrel. That 

Fig. 2. 

shown in the center of the photograph is cable No. 208. 

In addition to the experiment just mentioned, we placed in 
the bottom of manhole chamber No. 76, two short pieces of cable, 
one of which we connected by a wire to cable No. 208, which 
had been damaged by electrolysis. (It should be understood that 
the damaged cable had been repaired, and removed from the bot- 
tom of the chamber.) Fig. 3 shows the arrangement of this ex- 
periment. At the end of six weeks, the pieces of cable were re- 
moved and examined. The one which had been connected with 
cable No. 208, was deeply pitted,^ while the other piece was 
free from corrosion, as shown in Fig. 4, which is from a photo- 
graph of them. 

1. The plumbers of Omaha, Neb. apply the name of *• small-pox pipe" to 
that pitted by electrolysis. 



These experiments, with several others of minor importance, 
satisfied all who were interested, that electrolytic action was 
destroying cables, and probably gas and water pipes. 

It next became necessary to prove to the electrician of the 
railway company, that the current causing electrolysis, was from 
the railway system, and not from a leak in the Edison or some 
other electric lighting system. 

Measurements were made between the cables in all manholes, 
and the earth near the cables, for voltage and direction of current. 

a^ndit^ 4 i\^tm, Jh^*i. .Y,r 

Fig. 3. 

It was found that within a radius of about 2000 feet from the 
Albany street power-house, cables were negative to the earth, 
ranging from zero to 2 volts, and that outside of this neutral line, 
they were positive to the earth from zero to 12 volts. This con- 
dition prevailed until a point was reached near the East Cam- 
bridge power-house, when they again passed a neutral line and 
became more and more negative as that power-house was ap- 
proached. The same conditions were found as the AUston rail- 
way power-house was approached. On obtaining sufficient data, 




maps were drawn, showing voltage between cables and earth 
throTighoat all sections of the city. This is shown in map, 
Fig. 5. 

In addition to the figures placed beside the several routes of 
cable conduits, showing the direction of current and its pressure, 
we have colored red* such portion of the map where at that time 
we found the cables positive to the earth. We may call the red 
portion of the map, the danger territory. These potential meas- 
urements, though taken for other purposes, incidentally furnished 
all the proof needed to convince one that the railway power was 
the source of the troublesome currents. 

At the time the map was made, and previously, the railway was 

Fig. 4. 

operating with the negative pole of the dynamo to the trolley, 
the positive side being to the rails. 

Fig. 6 is intended to illustrate this condition. It shows the 
passage of current from the dynamo to the rails, and the passage of 
a portion of the current from the rails to the cables within the 
neutral or zero line, and from cables to rails outside of this zero line. 
The danger of electrolysis is only where the. current is leaving 
the cable or pipe through the moist earth, hence the dangerous 
district was at this time outside of the zero, or neutral line, as 
shown both on the map ( Fig. 5 ) and in this Fig. 6. 

Having outlined our early experience in running down this 
new trouble, we will next mention some of the proposed and ap- 
plied remedies. Several conferences were held for the purpose 



Fig. 5. — Showing where corrosion was going on when first brought to notice. 
The shaded portions of the map are referred to in the paper as colored red. 


of suggesting and discussing means for preventing the destruction 
of the cables, at which the oflScers and experts of both the rail- 
way and telephone companies were present, and it should be said, 
that the railway company in Boston has shown a disposition to 
adopt any promising plan for overcoming the evil, pave, perhaps, 
the abandonment of the rails and earth as a part of the circuit. 

First : It was proposed to remove all cables from the wet bot- 
tom and sides of the so-called manholes. It was found very 
difficult to place and retain cables free from the wet sides, and 
even could this have been accomplished, the action at the mouth 
of the ducts and within them, would still have continued. They 
were, however, all removed from the bottom of the manholes. 

Second: It was suggested that the cables might be (Connected 
to ground plates in the manholes, and so transfer the electrolytic 

Mm^^ m/\\\/j\\\\ 


Fio. 6. 

action to these plates, and thus save the cables. This experiment 
was tried on an extended scale, but though many ground plates 
having a surface of several square feet each, were connected with 
the cables over a large portion of the city, it was found that volt- 
meter readings taken between the cables and a point on the earth 
a short distance removed from the ground plate in any manhole, 
gave nearly the same pressure as l>efore the ground plates were 

In some cases, the voltage between the cables and the earth wa« 
reduced 25% ; in many others, no noticeable reduction was made. 
The ground plates were constructed from pieces of old lead cable, 
6 to 10 feet in length and embedded in the wet earth at the bottom 
of the manholes. It was evident from this test, that ordinary 
ground plates would not prove of material advantage for protect- 
ing the cables. 



Third : Prof. Elihu Thomson suggested, among other possible 
remedies, the placing of motor generators at different points 
along the railway line, wherever the cables and pipes are found 


Fig. 7. 

to be in danger, the motor generators to be operated by the rail- 
way power current; the secondary cumnt developed by these 
generators to be utilized to lower the potential in the cables and 
pipes to zero, with respect to the surrounding earth or rails. The 
suggestion included means for automatically starting and stop- 
ping the generators, as cables might become positive or negative 
to the rails. The motor generators would, so to speak, pump 
the current out of the cables, and force it into the rails whenever 
the potential of the former should rise above zero. Fig. 7 illus- 
trates this suggestion. This plan has not yet been put into 
operation so far as I am aware. 

Fourth : Insulating the cables and pipes from the earth was 
proposed. As some of the worst cases of corrosion of cables by 
electrolysis occurred where they were painted with asphalt. 

Fig. 8. 

taped, painted again, and finally covered again with a heavy 
braiding also saturated with asphalt, it was apparent that to insu- 
late cables sufficiently to protect them, would be difficult and 




expensive, if indeed practically possible. Figures 8 and 9 show 
specimens of corrosion of cables which had been treated with 
asphalt, tape and braiding. To protect water and gas pipes by a 
sufficient insulating jacket was seen at once to be impracticable. 
Fifth : Breaking the metallic continuity of the cable sheath 
and pipes was proposed. From the fact that severe action is 
frequently found in comparatively isolated spots, where cables 
and pipes cross each other, or pass near or across the rails, it fol- 
lows that any system of breaking the metallic continuity, would 
have to be studied with reference to the entire complicated sys- 
tem of pipes, cables and rails ramifying through the streets 
of a city. There would also be a diflference of potential between 
the several sections of cable or pipe, severed metallically, tending 
to cause electrolysis at one end of each section, as illustrated in 

Fig. 9. 

Fig. 10. In case of water pipes, treated in this manner, the ac- 
tion might be expected on the interior as well as on the exterior. 

There appears to be some evidence of such an action as this 
in gas and water pipes where the electrical continuity is partially 
broken by leaded joints. Fig 11 shows an iron service pipe 
from the Cambridge gas system. It will be noticed that the 
action is most severe at points immediately on either side of the 
coupling. The reason the corrosion appears on both sides of the 
coupling in this case is not clear ; it may be due to reversal of 
current on the railway system. We have observed other speci- 
mens similar to this, which may tend to show that for currents 
of low pressure, the resistance of joints materially aflfects the 
results. I will again refer to this question in connection with 
potential differences in water mains. 

Sixth : My assistant, Mr. Towne, suggested that the railway 



current might be so frequently alternated, as possibly to prevent 
serious action on the pipes and cables. The theory was, that be- 
fore the oxygen gas, liberated by the current, should have time 

"mi^ m^^ 

Fig. 10. 

to attack the metal, the reversal of the current would disperse it. 
A careful experiment was conducted, extending over a period 
of ten days, employing a pressure of current of from three to 
seven volts, and alternating its direction at regular periods of one 
minute, by specially devised apparatus. No material change had 
taken place in either plate during this period of time. We then 
considered the practicability of reversing the railway current 
frequently. It seemed possible to reverse it once each 5^4 hours, 
at a given time in the night when the load is comparatively 
light. To do this in a large system involving several power 



Fig. 11. 

stations would require either a loss of current for a few minutes 
in order to guard against one station reversing before some other 
had opened or reversed its current, or would require some elee- 




Fig. 12. — Condition after current was reversed by West End Co. The shaded 
portions of the map are referred to in the paper as colored red. 


trical BjBtem connecting the several stations together and opera- 
ting the reversing apparatus simultaneously. We concluded it 
would be very diflScult, if indeed at all practicable, to reverse 
such heavy currents during regular traffic. We then renewed 
the reversing experiment, giving 24 hour periods between each 
alternation, but found at the end of two weeks, to our sorrow, 
that the plates subjected to the action of the current were seri- 
ously electrolyzed. It seemed useless to pursue this line of 
work further at that time. When alternating current motors 
become practicable for use on street cars, advantage may be 
taken of the fact that such currents appear not to cause electrol- 
ysis to the extent of injuring pipes and cables exposed to them. 
Seventh : At about this stage in the study of the prob- 
lem, Mr. Fred S. Pearson, then engineer of the West End Street 


I^J L^ 


Fig. 18. 

Railway Co., made two suggestions which, though separate in 
themselves, and presented at different dates, yet carried out in con- 
junction, have proved exceedingly helpful in overcoming the diffi- 
culty, at least so far as relates to telephone cables. It occurred to 
Mr. Pearson first, that if the railway current should be reversed so 
that the positive pole would be connected with the trolley, the 
danger of electrolysis would be removed from the greater and 
more scattered portion of the city, and be brought near the power 
stations where it possibly could be more easily dealt with. This re- 
versal was made and the expected potential changes between ca- 
bles and earth followed. Fig. 12 is a map of JBoston, showing the 
condition after the reversal of current. The red or dangerous 
portions in this map, correspond to the white or safe districts in 
the map shown in the first of this paper (Fig. 5), the only varia- 
tion being, that by the reversal, the neutral or zero line was 




thrown oat a little farther from the Albany ' street power-house 
than it was located before. It was also noted that the cables near 
the power- hoase which had been from one to two volts negative 
to earth before the change of current, were now one to nine volts 
positive to earth ; that is, they were raised higher above .zero 
than they had been below zero prior to the reversal. Fig. 13 is a typ- 
ical representation of the current flowing through trolley, car, rails 
and cables at this time. It will be readily understood that with 
the conditions as illustrated in this figure, tlie electrolytic action 
would be confined to the territory comparatively near the power 
stations where the current is leaving the cables to reach the 
negative or rail side of the dynamo. 

Mr. Pearson next suggested the plan of running oat large cop- 

-^ LAJ 




Fig. 14. 

per conductors from the negative side of the dynamo and extend- 
ing them through the dangerous district, connecting them at 
frequent intervals to the cables. Fig. 14 diagrammatical ly illus- 
trates this plan.' On the principle involved in Prof. Thomson's 
motor generators, this low resistance conductor connected direct- 
ly to the dynamo, was to punap the current from the cables and 
so prevent its passage into or through the moist earth. Some 
of us were skeptical as to the completeness of this proposed 
remedy. It seemed possible that even with such a good return 
condactor. some of the current might still pass into, and through 
the earth. Voltage measurements, however, at once dispelled 
the doubts, for we found that the cables measuring 9 volts positive 
to earth, gave a reading of 22 positive to the return conductor ; that 



is, the return wire as relating to the cables, was at all points, more 
negative than the earth (if we may be allowed the expression). The 
return conductors were made up of a large number of No. 18 
copper wires formed into cables about one inch in diameter, 
known as conductors of 500,000 circular mils. These conductors 
were extended in each direction from Albany street power-house 
entirely through this dangerous district, its longest section being 
about 4,300 feet. The cables in every manhole within the district, 
were connected by several No. 12 copper wires to the return con- 
ductor and soldered. On first connecting the cables to the return 
conductor, which took place Dec. 24, 1892, the current was 
sufficient to melt several strands of No. 12 wire. A measure- 
ment for current flowing in the main return conductor which was 
used for relieving the cables only, gave over 500 amperes. 

It may be interesting here, to note comparative voltages in the 
district near the power-house, as given in the accompanying table. 

Ketween Cables 

Manhole No. 

Fine Measure- 
ment to earth. 

After Reversal 

of Railway 


Between cable 
and Return 

and Earth after 

Return Con- 
ductor was con- 
nected to Ca- 






4-5 — 


1.5 -- 

2. - 


22 - 


4 5 — 


0.5 -- 

05 - 


22 - 


0.5 — 

2.8 H 


22 - 


C.8 — 




22 - 


I. — 

5- H 


22 - 


2. — 


»-5 — 



72 - 


«-5 — 




22 - 



22 - 



2. — 





'5 — 




22 - 


05 — 


9- - 



I. — 



9. - 


22 -f 




0.5 + 

7. - 


22 - 


2. — 


2. - 





2. + 

0.5 + 

22 - 


5- - 


X. — 

32 - 


75 — 


3- - 


2. — 

22 - 




1. - 


0.3 — 






0.5 j 










22 - 



0.5 — 

4. - 


22 - 



I. — 

4. - 


22 - 


3. - 


X. — 

2-5 H 




2. — 



22 - 





22 - 




1. — 





Fig. 15 is from a photograph taken in one of the manholes 
showing the connection of the cables to the return conductor; the 
limited size of the manhole prevented my obtaining a view of all 
the cables. 

The mip, Fig. 16, illustrates the condition after the installation 




of the return conductor at the Albany street station. The red 
patch which existed in that locality is now removed, and the 
cables are all negative to earth. The remaining red patches or 
dangerous sections were corrected by taking similar means of 
reaching the East Cambridge power-house. In treating this lat- 
ter case, many measurements were made to determine whether or 
not the railway return wires put up to take the current in a 
measure from the tracks, would answer for a return for the cables 

Fig. 15. 

instead of using a special return conductor as had been employed 
at the Albany street district. It was found that they would not 
serve the purpose, since the potential of these track return wires 
varied constantly and was frequently above that of the earth. 

The cables on the Boston side of the draw of West Boston 
bridge, proved to be positive to both the rail and the water, 
while on the other side of the narrow draw, the opposite condition 
existed, showing at once, that it was unsafe to assume any neu- 


Fio. 16. Condition Jan. 4. after connecting West End ground wire to cables 
near Power Station. The shaded portions of the map are referred to in the paper 
as colored red. 


tral lines or potential difference, witliont making measurements to 
determine the absolute facts. 

So far, this paper has dealt particularly with the subject of 
protection of lead covered cables. It might be inferred that 
water and gas pipes can be treated in precisely the same manner 
with the same results, or as water pipes have a much greater 
sectional area of metal, it might be presumed that simply a con- 
nection of such pipes to the dynamo at the power station would 
be sufficient to bring their potential down to zero throughout the 
dangerous district. The facts so far coming to our notice, would 
materially modify such inferences, and therefore should find a 
place here. 

That iron pipes are as truly subjected to the corrosion as lead, 
need not be stated to the members of this society, but for the 
benefit of city officials and others who may read the paper, it 
should be plainly stated that they are quite as readily destroyed 

Fig. 17. 

by electrolysis. Fig. 17 is from a photograph of an iron gas 
pipe taken from Brooklyn, N. Y 

The City Engineer of Milwaukee, Mr. G. H. Benzenberg, has 
kindly sent me a photograph of a six-inch iron water main, badly 
corroded. It is the best specimen of cast-iron pipe I have been 
able to obtain, although not the most serious case of corrosion. 
Fig. 18 is from the Milwaukee specimen. 

Mr. Benzenberg writes that the trouble in that city was chiefly 
noticed upon the six-inch water main extending 100 feet on each 
side of a point opposite the railway power station. Services en- 
tering this main were also destroyed, and all were renewed three 
times during the past two years. He states further, and I quote 
his own words, " at other points where power-houses were estab- 
lished thereafter, the mains were immediately connected by extra 
heavy copper wires with the generator ; we have had no trouble 
with them so far". 



Mr. O, H. Tripp, engineer at Rockland, Me., recently fur- 
nished me with a specimen of wrought-iron pipe destroyed in five 
months ; the fact is of special interest as it comes from a city 
having but a small railway system. 

In Boston, there have been water, as well as gas service pipes 
corroded through by electrolysis. I have not learned of any 
mains having burst from this cause. Measurements of water 
pipes in the city indicate they are still in danger, notwithstand- 
ing several thoroughly made connections with the pipes at the 
power station ; the same is true in Cambridge, Mass. This leads 
me to call attention to an interesting series of inquiries. 

Fig. 18. 

The engineer of the Water Board at Rochester, N. Y., sug- 
gested to me, a short time ago, while looking into the question 
of electrolytic action upon the pipes in that city, that possibly 
there might be gufiicient resistance in the joints of the water mains 
to cause an action upon the lead ring which forms the connection 
between sections of pipe. He stated that not unfrequently there 
is found a film of moisture between the pipe and this lead ring, 
and as the pipes are coated with a preparation of tar or asphalt 
on both the inner and outer surfaces before they are laid, there 
might be a poor electrical connection. Without having made 




any inquiries or tests upon this point, it seems to me probable 
that the careful calking which is given these lead rings, would 
form in some portion of each joint a good electrical connection ; 
that is, one of very low resistance. Recent measurements how- 
ever made in Boston, and others made in Albany, during* the 
latter part of March, this year, convince me that there is a very 
appreciable resistance in such joints. 

Fig. 19 will illustrate the conditions at Albany. We found 
the negative side of the dynamo to be connected with the rails, 
and with ground plates in old wells; no connection had been 
made with water or other pipes. Directly in front of the 
power station the voltmeter indicated a })ressure of 20 volts 


Water pipe 



-1flOO-F*ET— - 





Fig. !•. 

between water pipe (an 8 inch cast-iron pipe) and the rail, the 
pipe being positive. A reading taken about 300 feet in either 
direction, up or down the street, indicated about 18 volts. At a 
point 1200 feet north, the reading was lowered to 12 volts. "We 
then connected the rail side of the dynamo to the street hydrant 
and took new readings, finding 1 volt at the station, 7 volts at 
300 feet distant, the same south, and 8 volts at a point 1,200 feet 

These measurements, with similar indications in Boston, show 
plainly that there is a very appreciable resistance in the 
water-main joints. At the same time the measurements give 
fair evidence that the difference of voltage between any two 
sections of water pipe is very small. The interested parties at 
Albany have kindly consented to allow any facts or figures ob- 
tained there in reference to this subject to be placed in this paper. 


Fig. 20 is from a photograph of a piece of lead service pipe 
at Albany. 

A few measurements made through the danger district will be 
of interest. The station is situated near the southern extremity 
of the city. The danger district extends north about one mile, 
and over this portion of the district the following figures were 
obtained. They were taken at nearly uniform distances of about 
500 feet, beginning at the station. 


At Station, Cable to £arth, Po&itiye, 12 yolts. 

" " Kail •• 25 '* 

Water " •' '• 20 '* 

600 Ft. North, Cable " Earth ^. *' 10 •* 

'• •' Track '* 22 •' 

Water'* '' '* 12 " 

1.000 •• Cable " Earth •' 6 '' 

" " Track " 18 •* 

Water •• " '' 12 •* 

1,500 " Cable •* Earth •' 6 '* 

'* •' Rail '• 18 *' 

Water" " " 18 " 

2,000 ♦* Cable "Earth " 8 *' 

'' •• Rail *' 16 *' 

2,500 •' •* ** Earth " 6 " 

" "Rail '' 13 " 

Water" " " 8 " 

8,000 '• Cable •• Earth •' 4 " 

*' " Rail * 11 '• 

3,500 * " '* Earth " 8 '* 

•• '* Rail ♦• 12 " 

Water" " " 7 " 

4,000 " Cable *' Earth " 8 " 

•* '' Rail " 8 " 

4,500 " •' '* Earth " 1 " 

*' •* Rail " 1 " 

Water *• " Negative 1 '* 

5,000 •' Cable •* Earth Positive i " 

'• '* Kail " i " 

It is proposed at Albany to extend large wires (0000) through 
the dangerous district, one wire for each system of pipes, con- 
necting the pipes to them at frequent intervals. 

It is probable that the remedy which has been applied to tele- 
phone cables in some cities, has been the more positive from the 
very failure, so far, to thoroughly protect the other systems of 
pipes against electrolytic action. Fig. 14 (already shown) may 




assist to a clear understanding of tliis. The cables are ht^re 
connected by a large wire to the dynamo, while water pipes 
are not so treated. Therefore, the current which enters the 
water pipes at points outside the danger district passes to the 
neighborhood of the power station, and, in leaving them there, 
raises the potential of the earth about the cables. In other 
words, the current flows from the water pipes to the ground and 
thence to the cables in order to reach the dynamo. 

Connecting any one system of pipes to the dynamo, will, in a 
measure, protect other systems of pipes, but connecting all sys- 
tems leduces the certainty or margin of certainty of protection 
to any one system. This will be apparent from a little study of 
Figure 14 just referred to. 

When all cables and pipes in the danger district, are connected 
by sufliciently large conductors to drain them, a careful adjust- 

FiG. 20. 

ment in resistances in these several conductors may be found 
necessary in order to insure a balance between the several sys- 
tems of pipes. It may lead to the necessity of reducing the 
carrying capacity of the conductor returning to the dynamo from 
the rails themselves. 

The question has already arisen, and it doubtless will be re- 
peated here, — " How small a difference of potential between pipe 
and earth will cause electrolytic action ? " In reply to this, it 
may be stated that some of the worst cases of corrosion in Boston, 
have occurred where the difference was but one and one- 
half volts. Mr. A. T. Welles, of Chicago, in describing to me 
an examination of some of the first cases in Cincinnati, states 
that the " difference of potential between the cables and the rail, 
was never more than one-half, and usually less than one-quarter 
volt." Such a difference between cable and rail would mean a 
much less difference between cable and earth, where electrolysis 


takes place. Mr. John C. Lee, of Boston, has experimentally 
caused the corrosion on lead and iron by a difference of potential 

of T^TT VOlt.^ 

These facts certainly indicate that but a very small pressure is 
necessary to produce the action and should dispel the numerous 
statements that well bonded rails or a large amount of rail return 
wires will alone overcome the trouble. In some cities, where 
electrolysis is in progress to-day, the return copper nearly equals 
that of the trolley and feed wire system. We cannot force the 
current to take one path exclusively when others are open to it. 

The facts given above, with others similar, though not enume- 
rated, lead me to these conclusions : 

Ist. All single trolley railways employing the rails as a portion 
of the circuit, cause electrolytic action and consequent corrosion 
of pipes in their immediate vicinity, unless special provision is 
made to prevent it. 

2nd. A fraction of a volt difference of potential between pipes 
and the damp earth surrounding them, is sufficient to induce the 

3rd. Bonding of rails, or providing a metallic return conductor 
equal in sectional area and conductivity to the outgoing wires, is 
insufficient to wholly prevent damage to pipes. 

4th. Insulating pipes sufficiently to prevent the trouble is im- 

5th. Breaking the metallic continuity of pipes at sufficiently 
frequent intervals, is impracticable. 

6th. It is advisable to connect the positive pole of the dynamo 
to the trolley lines. 

7th. A large conductor extending from the grounded side of 
the dynamo, entirely through the danger territory and connected 
at every few hundred feet to such pipes as are in danger, will 
usually ensure their protection. 

8th. It is better to use a separate conductor for each set of 
pipes to be protected. 

9th. Connection only at the power station, to water or gas 
pipes, will not ensure their safety. 

10th. Connection between the pipes and rail, or rail return 
wires, outside of the danger district, should be carefully avoided. 

1. Experiments completed since the writing of the paper produced marked 
corrosion by currents of less than \ volt, this was illustrated by a lantern slide, in 
which the pieces of lead wire themselves were shown magnified upon the screen. 


11th. Frequent voltage measurements between pipes and earth 
should be obtained, and such changes in return conductors made, 
as the measurements indicate. 

In closing this somewhat rambling paper, I can do no better 
than use words which will remind you of Patrick Henry; ^eternal 
vigilance " will be the " price " of pipes and cables where con- 
ditions favorable to electrolysis exist. 
Boston, March 80, 1894. 

At the conclusion of the paper, the author presented a 
number of views upon the screen, in addition to those which 
form part of, and are printed in the body of the paper. 

Among the most interesting were : 

1. A map of Boston, showing the district in which the water 
pipes (by recent measurements) are in danger of electrolytic 

2. Man^ samples of electrolyzed pipes, both iron and lead. 

3. Specimens of lead pipe, snowing the effect of corrosion pro- 
duced by a current having a pressure of less than one-half volt. 

4 Two views, showing method of making the voltage meas- 
urements between pipes and the earth. 

5. A view, showing the process of electrolysis going on, by 
which a tinfoil pipe was eaten through, allowing a colored liquid 
to mix with water, and making a very interesting picture on the 



The President :— I will call on Professor Plympton to open 
the discussion on this interesting paper. 

Prof. Geo. W. Plympton :— 1 came here as a learner to-night. 
I had many questions to ask, and a good many have been answered 
by Mr. Farnham's paper. I have been accustomed ever since I 
had any experience with this troublesome question to consult Mr. 
Farnham's opinions, which I have obtained frequently at second 
hand through the scientific papers. We have a large mileage of 
trolley in Brooklyn as everybody knows. The papers assure you 
of that every few days. Our first experience with electrolysis 
dates from about a little more than a year aco. We had heard 
of that in Boston, of course, before we had any experience in 
Brooklyn. In framing the franchise for the trolley roads there 
was fortunately a clause inserted, not through any provision of 
the aldennen or commissioners, but which placed responsibility 
upon the trollev companies for anv mishaps to any undergroun(l 
pipes, wires, cables or the like. That was placed there, not be- 
cause electrolysis was thought of at the time, I think, but because 
it was supposed that in the process of digging un streets thev 
might interfere with gas and water pipes, so that tne responsibil- 
ity is clearly acknowledged and they accept the situation, and they 
are taking all the means that they can with due regard to econo- 
my, which they always observe, of course, to prevent any serious 
deterioration. So in their experimenting, as tliere are four com- 
panies and four sets of engineers, their experiments have been 
to some extent along different lines. I am sorry to believe that 
we have not got the full measure of the damage that has been 
done. So much as has been exhibited, and you saw some of the 
specimens on the screen, was such as has made itself known 
tnrough the entire failure of pipes and cables. It is reasonable 
to suppose that ten times as many examples could be found which 
would be nearly as bad as those exhibited, because there has been 
no digging down in the ground in search of such cases of corro- 
sion. Water pipes, gas pipes and lead coverings of cable have 
all suffered. Telephone companies were the first to find it be- 
cause of slight perforations of the insulation. Leakage of water 
pipes have made themselves known in one or two cases where 
they were near enough to the surface. In one of the cases ex- 
hibited, one pipe had been destroyed in three or four months. 
It was an iron pipe very near the rail. It was replaced by a 
larger pipe, and tnat was perforated in thirty days. So that the 
rapidity of the action warned us there, that it was time to look 
about quite actively. We have held numerous conferences with 
the engineers and they have promised to take all proy^er means 
for taking care of their own current. That is the thing, of 
course, for the trolley people to do. That they are aware of ; 
they have been sufficiently warned of it. One thing I feel a 
little concerned about, and I take time only to mention it and 


that is this seventh conclnsion : " A large conductor extending 
from the grounded side of the dynamo, entirely through the dan- 
ger territory and connected at every few hundred feet to such 
?ipe8 as are in danger will usually ensure theirprotection." 
'rue, so long as that connection can be kept up. Will it not be 
necessary to make such a connection in such place that we can 
examine it everj once in a while ? Will it do to make a connec- 
tion and cover it up ? What shall it be — copper wire ? Can we 
solder a copper wire to an iron pipe ? Can we make a connection 
that will remain good and without increasing its resistance ? Lo- 
cal action will set up a corrosion, and as to soldering, in the 
ordinary sense of the term, it seems to me impracticjible. So 
that we have some fears that whatever precautions they take of 
that kind, may prgve insufficient after a little while or else that 
they will need constant attention, and that we shall need a large 
corns of inspectors to prevent serious injury. 

The numerous ways of bonding the wires are the things that 
the trolley people exhibited there as the means of preventing 
injury, and two or three have been exhibited in the last week or 
two. One, that of making the rails continuous has been, I believe, 
tried in Boston. It is about to be tried in Thirty-ninth street, 
Brooklyn. The apparatus arrived the other day for welding the 
rails. The engineer of the company assured me that they would 
make their rails continuous within the limits of the city. An- 
other bond, which bears the name of Vail, I think, has been 
suggested, where three large rivets are made tapering, and driven 
into the rail and riveted down, each rivet, half an inch in di- 
ameter, and then with a half -inch conductor extending beyond 
the joints, and then another set of three rivets. That has been 
exhibited as one of the best bonds that is known. 

Of course, as Mr. Famliam says, the current will still be 
divided between the rail and the moist earth in' proportion to 
their relative conductivities. You cannot convey all of that 
current back by the best conductor that you cai» put in the 
ground. So the method of relieving the pipes of that positive 
charge, where the corrosion has been set up, is the best way to 
ensure the protection. But in regard to its permanency, as I 
said before, I am inclined to feel some fear. 

The question with us, of course, is in the experimental stage. 
We shall accumulate more within a year, but in that time I fear 
we shall find a good deal more damage done, for the reason that 
it is onl V where the corrosion has been so bad that the pipe or 
the cable has failed, that our attention has been called to it. No 
doubt corrosion is going on at this hour over a very large extent 
of territory. We sliall accumulate more information, I presume, 
within the next season. But for the best we have been able to 
do, with the information we had, we felt all the time indebted 
to the very able and systematic way in which the investigations 
have been carried on, and the methods taken to ensure success in 


Mr. T0WN8END WoLcoTT : — One very intereeting point is the 
small voltage which will corrode a cable in the eartn. We are 
generally familiar in electrolysing solutionfi with voltagee of one 
volt or over — almost any solution — over one volt. But I take it 
that the conditions in the damp earth are such that the corrosion 
is just about ready to go on anyway, and a very little help will 
make it go. In decomposing water, for instance, it takes about 
1.48 volts, if I remember ; but in that case you have to supply 
the energy to break up the chemical combination. But the way 
it probably is with a cable in the earth, the chemical action is 
just ready to take place, and it only requires very little to 
start it. 

With regard to the question about the voltmeter, it may be 
well enough to say that, if the voltmeter has high enough 
resistance you do not have to be at all particular about contacts. 
With a high resistance voltmeter you can take a storage battery 
out of the solution, and when it is apparently dry you get ex- 
actly the same voltage as with the acid. A low resistance volt- 
meter, of course, would not show that. But if it is a high 
resistance voltmeter it will give the full voltage. 

Mb. a. E. Kennelly : — Mr. Chairman and Gentlemen, I 
think that I only echo the general sentiment in saying how 
much I have enjoyed listening to the paper of the evening,"which 
is the first, I think, that has given us clear and precise mforma- 
tion, thoroughly and interestingly placed before us, upon this 
subject which is of great practical importance. But in some of 
the generalizations which Mr. Famham makes, I have the honor 
to diflEer from him, and I beg to submit certain criticisms upon 
them. I wish to take the stand that it is not, as stated in the 
sixth ffeneralization — that it is not necessarily good policy to con- 
nect tne positive pole of the dynamo to the trolley lines, and for 
this reason, that supposing you are grounding one terminal of 
your dynamo which is supplying a total current distributed to 
your trolley* wires, say of a thousand amperes, that thousand 
amperes goes into the ground on your district, and it has to 
come out of the ground at the point of your ground connection 
to the dynamo. Kow, if you bury in the ground a large mass 
of iron pipe, or lead tube, or metallic conductor of any kind, 
that metallic conductor will, perhaps, absorb a large fraction of 
the thousand amperes. Let us say it absorbs 750 amperes. The 
metallic system will have 750 amperes entering it and 750 am- 
peres issmng from it. Now, when you have tlie negative pole 
to line, the current will go from your ground plate, will enter all 
this mass of metal in the vicinity, and there it will do no dam- 
age, because where it enters the iron or lead, hydrogen is given 
on, as we have seen represented on the screen. But it will issue 
from the iron or lead over a larger area in the remote districts — 
a very large " danger " area, an area as shown on the chart this 
evening of several square miles. That large area will be in 


danger of corrosion, and there will l>e corrosive electrolysis go- 
ing on all over that area to the extent of 750 amperes collec- 
tively. But when you reverse the current, as is suggested as 
advisable in the sixth conclusion of this paper, you reverse that 
condition of affairs. All the distant district is hee from danger 
and all the oxidizing and corroding effect is close to you ; but 
the 750 amperes are still there and are now actively corroding 
a much smaller surface. It is the surface in the immediate vicin- 
ity. Instead of being spread over, as shown on the map in the 
previous case, several square miles, the same Jtotal corrosive 
electrolysis is spread over, perhaps, half a square mile. The 
danger area is reduced, but the danger is greater, because the 
activity is consequently augmented in that district. You have, 
say, twenty times the amount of corrosion going on over a given 
siirface of pipe, and the result is you will eat through those 
pipes twenty times as rapidly, and if the danger is in bursting a 
pipe you will probably burst it twenty times as soon under those 
circnmstances. But if, as Mr. Famham says, we prevent that, 
as was done so skilfully in this case, by throwing out a ground 
feeder, which prevents the current from emerging out of the 
pipes into the surrounding soil near the power-house, why then, 
coupling together the sixfli and the seventh conclusions, all is 
well ; you have stopped the corrosive action. But unless you do 
couple together the sixth and seventh suggestions, you are likely 
to cause more danger by having the positive pole to line, than if 
yon have the negative pole to fine. The fact Mr. Famham men- 
tions, that he did have trouble with his lead-covered cables while 
the negative pole was to line, but did not have trouble when the 
positive pole was to line, is an argument in his favor. But he 
would probably have had electrolysis on the cable in one district 
or anotner whichever happened to be the danger district, if the 
lead had been suitably placed for electrolysis, and a lead cable 
of this kind is singularly liable to be spoiled by electrolysis. 
The resistance of an ordinary lead telephone cable sheath, as we 
know, is much greater than that of a large iron water pipe. 
But being continuous, and having very few or no unsoldered 
joints, it has far less resistance than a large iron pipe with a 
large number of poor electrical joints. The result is that where 
there is an opportunity for the lead sheathing to be corroded at 
any point, there will be active corrosion, and at that point those 
destructive effects so fully brought out in this paper will be 

Furthermore, I would like to point out that the difference of 
potential as measured by a voltmeter between a cable sheathing 
and the ground in its vicinity, is not necessarily a criterion of the 
degree oi corrosive activity taking place at that point. If the 
direction of the p. d. is such that the cable is positive, there will 
be a corrosive current there, or a tendency to produce a corro- 
sive current. But if the p. d. is three volts or four volts, the 


corrosive current is not necessarily twice as strong as if the p. d. 
were one and a half or two volts respectively. For suppose yon 
had a perfectly insulated cable and sheath, but at some distant 
point, say, half a mile off, the sheathing of lead was exposed to 
the ground, and that there destructive action was beinff produced ; 
there might be at that noint, half a mile away, a difference of 
potential between sheath and the ground of three volts, bnt at 
the point where you stand the p. d. might happen to be five 
volts. Now, the five volts conld not be so active in producing 
corrosion as the distant three volts, in fact it could not be active 
at all, owinjg to the perfect insulation of the entire cable in the 
vicinity. The point I want to make is, that though the observed 
p. D. is an evidence of action, it is not an evidence of qnantita- 
tive or cori'esponding intensity of action. 

Again, while all admit that iron is corroded, and iron pipes 
are corroded electrolytically, and the evidence has been amply 
brought forward to-night, I do not think that Mr. Farnham 
means that as much corrosion takes place with iron as with lead, 
for the reason that we all know a given weight of lead is much 
more readily consumed by electrolysis than a given weight of iron. 
Roughly, an ampere in a year will dissolve seventy-five pounds 
of lead by electrolysis. It will dissolve, roughly, only about 
twenty pounds of iron, or nearly four times less. So you have 
a more reduced activity of corrosion on an iron plate than on a 
lead plate, and that is reduced again by the fact, m actual prac- 
tice, that in water mains, the electrical conduction from length 
to length of pipe is very imperfect, as evidenced, for example, 
by the tests and measui'ements shown on the screen in the last 
diagram, Fig. 19, where we had an indication of two volts fall 
of potential per hundred feet of pipe within the first three 
hundred feet from the station. 

The destructive effect of electrolysis, while it is serious, is 
often exaggerated by not taking into account the actual amount 
of decomposition that can take place, electrolytically, under the 
most favorable circumstances, if you have a mile of eigliMnch 
water main, which is half an inch thick, that is, its exterior di- 
ameter is nine inches and its interior diameter is eight inches ; 
and a thousand amperes are kept steadily flowing day and night, 
with uniform density, out of that surface into the surrounmng 
soil, it will take about six years ihv that current to reduce, by 
electrolysis, the thickness of the iron to one-half. Of course, it 
would be* unfair to make a positive statement of that kind, he- 
cause we assumed uniform corrosion, whereas corrosion does not 
take place uniformly. 

The resistance of the ground is really far higher than we 
ordinarily attribute to it. We are so accustomed to use the 
ground universally in telegraphy, we are so accustomed to the 
idea of a ground return circuit with verj^ little resistance in it, 
that we come to grasp the idea, unconsciously, that the ground 


has very low resistivity, whereas it has very high resistivity. We 
may taxe the position, in fact, that the ground itself has an 
enormous resisivity, and what we really measure in the resistance 
of the ground, is the resistance of the water that happens to be 
suspended in the ground. The resistivity of ground under ordi- 
nary circumstances is something like 60 or 60 ohms. The result 
is, that if you had two iron water pipes, each nine inches in di- 
ameter, deeply buried in the soil, ana 30 feet apart, at a constant 
difference of potential of ten volts, you would not expect less 
than 2.5 ohms resistance between the pipes per linear foot of 
either, nor more than four amperes oi current between them 
per linear foot. In the case of ten volts between one such 
Duried pipe and two surface track rails, supported on wooden 
sleepers, the resistance between track and pipes would probably 
be much more, and the current strength per linear foot of pipe, 
perhaps less than one ampere. 

One of the most interesting observations that ever fell to my 
lot, in connection with the high resistivity of the ground, is, 
perhaps, worth mentioning. It was occasioned by trouble in an 
Edison tube, and the fault, a ground, was situated about three- 
quarters of a mile from the station. We were trying to locate 
the ground by means of a compass needle moved over the sur- 
face of the soil and over the buried conductor, while strong 
direct currents of about two seconds duration were applied with 

f round return circuit, every three or four seconds in the power- 
ouse. We took the magnetic needle along the surface of the 
trench and tried to find a point where the needle ceased to re- 

rnd to the intermittent currents. We came to a spot where 
line of Edison tubes departed from the road and entered a 
field. Round the field there was an iron wire fence with iron 
uprights, which fence ran for several hundred feet parallel to 
the road. We knew that the ground existed in the iron Edison 
tube somewhere in this vicinity. I happened, auite by accident, 
to stand near the fence, looking in at the fiela and wondering 
where the trouble might be, and as I rested my hand on the 
fence, I fancied I felt a shock. I thought this a mere delusion 
and paid no attention to it. But presently some one else came 
up, and without any suggestion on my part, rested his hand also 
on the fence and declared that he felt a shock, and finding my own 
imagined sensation corroborated independently, A^e investigated 
it and found the reason to be this : within 20 feet of the fence 
was the " ground " we were seeking in the Edison iron tube. 
The intermittent current escaping from the conductor into the 
iron tube 30 inches below the surface of the soil, was able to 
raise the potential of the surface of the road in the vicinity 
where we stood, to such a degree that we were able to deliver 
through our hands enough current to the iron fence wire to 
make a shock perceptible, and, on taking measurements later on 
with a galvanometer we found the resisivity of the soil, which 
was damp, but not wet, to be something like 60 ohms. 


There is a very curious, although not very essential, point 
brought out in tnis interesting paper, and that is the exten- 
sion of the neutral line at the time when the reversal was made 
in the direction of current to the trolley lines. • It was pointed 
out in the paper that the zero line of pressure moved further 
from the station when the reversal was made. I would like to 
ask Mr. Farnham if he has any information which would throw 
light on this interesting peculiarity. In the absence of any in- 
formation, I might suggest that possibly the counter-electromo- 
tive force of the developed hydrogen over the surface at which 
the current entered the system oi 4)ipes, might be sufficient to 
disturb the zero line. 

Mr. Farnham: — I will say in reply to the question, that we 
have made no special investigation, nor have we found any par- 
ticular reason to account for the neutral line being thrown out 
from the station by the reversal of the current. But measure- 
ments obtained several weeks after the change was made, as well 
as immediately at the time, gave the same result. It would seem 
to me that this rather disproves the hydrogen theory : that is, 
the zero line has continued farther out than when tne current 
was in the opposite direction. 

I would like also to say in reply to the able remarks just g|iven 
to us, that the conclusions summarized in this paper were written 
with the thought that they should be considered together in all 
cases. There would be no advantage in doing some of this work 
suggested unless we did other parts of it also. Conclusion No. 
6 was intended to go with No. 7. But if that had not been the 
intention, I can hardly agree with the speaker that it would be 
more serious to have the corrosion take place in a limited terri- 
tory, even though it were more rapid, than in a large territory. 
Would it be more convenient to dig up all the paved streets of 
a large city once in ten years, or to dig up a radius of a thousand 
or of two feet once in a year ? It is an open question which 
hydraulic and gas engineers must pass upon. But it would 
seem to me better to confine the trouble in a small territory, 
even though you had to take other measures, put in larger pipes 
if you please, in that territory, rather than have the destruction 
slowly but surely going on all over your city ? Is it not prefer- 
able to have a very sore finger than to be moderately sick all over? 
The suggestion of putting the positive side of the dynamo to the 
trolley and thereby bringmg the danger territory near the station, 
was primarily for the purpose of rendering it more easy to treat 
the trouble with the return wire system which I have described. 

I would like also to remark in connection with the first speaker 
who opened the discussion, that I reco^ize the importance 
which he named, and the difficulty of havmg a good connection 
with all the pipes. As to how the connection should be made 
on water pipes has been considerably discussed. I am hardly 
able at present to advise. Whatever we do in this line we must 


watch constantly. We must take our voltage measurements 
frequently, as noted in conclusion 11. We can tell certainly by 
this whether there still is danger or not. As to the number of 
years that may elapse before pipes will be eaten through, is a 
question we hardly need to discuss. If the action is slow it 
ousht to be prevented. We may easily determine whether there 
is danger or not, and whatever we do to remove the danger by 
these means, we must watch the electrical conditions constantly 
or we shall find ourselves again in trouble. . 

In illustrating this fact let me say that since the system just 
described has been applied in Boston, the West End company 
has run out in one direction several large return wires in addi- 
tion to those previously in use in that locality, and thus practi- 
cally moved the power station, that is, it changed the zero line 
from its former location to a point very distinct, making it 
necessary to rearrange and extend the cable return wire system. 

The Secretary read the following communication from Mr. 
Thomas D. Loctwood : 

Mb. Lockwood: — I much regret my inability to be present 
when Mr. Famham's excellent paper, at which I have nad an 
opportunity to glance, is read. 

I have admired greatly the philosophical spirit in which Mr. 
Famham's researches have been made, and am greatly pleased that 
he has found time to prepare and deliver to the Institute an ac- 
count of them, and desire to place on record my personal opinion 
that the paper is one of the most interesting, and at the same 
time, one of the most lucid and valuable contributions to the 
Tbansactions of the Institute that have been received. 

It is eviden.t that with the plus pole of the generator to line, 
the tendency of the trolley current will be to pass at all outlying 
points to the pipes and cables which lie in its path, except at 
points which are closely adjacent to the generator. 

But when the minus pole of the generator is connected with 
the trolley and feed wires, the current, or some portion of it, 
having once strayed upon the pipes and cable tubes lying gener- 
allv in its way, tends to leave them at all outlying points. 

In the second case, then, the destructive erfects of electrolytic 
decomposition tend to become widely distributed, while in the 
former case, they tend to concentration. 

A superficial examination might lead to a superficial conclusion 
that, because of such distribution and division, the arrangement 
in which the minus pole is placed to line, is under all conditions 
the most desirable and advantageous, because by reason of such 
division the strength of current leaving the pipes at any one 
point, would be relatively small, and possibly so small as to be 
nefflible and innocuous. 

On the other hand, under the arrangement which provides that 
the plus pole shall be to line (if pipes, or lead covered cables 
enter at all into the question), a current of very considerable 


volume may be ooncentmted in a very small area of space, and 
is liable to bring about in an extremely brief time, intensely 
destructive corrosive effects at points within such circumscribed 

I do not say that because the first named conclusion is super- 
ficial, it is under all conditions incorrect, and conditions can 
readily be conceived, such as those concerned in the operation 
of a railway in a small place, or on a lightly traveled trunk line, 
where it might even present preponderating advantages. 

It seemSjTiowever certain, that for city work, and under all 
conditions where traffic is heavy, and cars numerous, and current 
consequently of great volume, it is (so far, at least, as this pheno- 
menon of destructive decomposition is concerned) infinitely more 
advantageous to connect the plus pole of the generator to the 
line, and thus concentrate the electrolytic effects to a limited area 
near the source of current, where it can readily be located and 
where preventive as well as remedial measures can be applied 

I am heartily in accord with the propositions of the paper, 
and do not doubt that the familiarization of our minds with this 
important subject will be productive of beneficent result. 

A Member': — I would like to ask Mr. Farnham what he esti- 
mates would be the relative cost of the overhead copper, and the 
cost of the underground copper to properly protect a system 
such as the Boston system, relative to the overhead structure, in- 
cluding the bond wires. Would it be larger, or about the same ? 

Mr. Farnham : — I should think it would be very much smaller. 
As I have shown you, the danger district extends only a com- 
paratively short distance from the station, and a modeiutely sized 
wire will overcome any trouble in that district. I should say the 
amount of copper to prevent the trouble would be very small as 
compared with the overhead system. 

A Member : — I believe that in Brooklyn vou use overhead 
structures, do you not, for the return { Has there been any sign 
of corrosion near to it ? 

Prof. Plymton : — It is different for different roads. They 
are trying all sorts of things. That is one. I think there has 
been no corrosion. But the time has been too short to announce 
it a success. ' 

Mr. Farnham : — I want to add one more word. Allusion is 
made again to the possible advantage of putting the positive 
side of tlie trolley to the ground in small places. I will simply 
call your attention, as some of the members may wish to look 
up the matter, to the English communication. It is in the 
London Electrical Engineer of April 6, 1894. The writer of 
the article states his assumption of fact very positively, and he 
also uses as an argument that this method will cure the trouble, 
that in their " large " system where this has been applied, some- 
thing like 900 amperes of current is used to run the cars. Now, 




this is not a " large " system as we all know. Nine hundred am- 
peres is a small amount to use on a city railway system, and the 
fact that the engineers have not found any pipes eaten through 
since they made this provision is no proof at all that the action 
is not progressing. I do not believe it is advisable to wait until 
pipes have been eaten through, before we know whether the 
thing is taking place or not. 

I would like to say one other word and that is, that while a 
moderate sized wire running through the danger district will re- 
move the current from pipes it will not do it, of course, if you 
extend that wire indefinitely. 

If you extend the return wire throughout the entire railway 
district, and connect it at frequent points to the water or other 
pipes, as I understand has recently been done in Milwaukee, you 
may prevent a difference of potential between the rails and the 
pipes, but you will not wholly prevent a difference of potential 

Fio. 21. 

between the pipes and tlie earth. You will simply transfer the 
action from the pipes near the power station to those in more 
distant territory ; for in this case, the current will naturally leave 
the pipes at the same point it now leaves the rails, though in a 
less quantity (see Fig. 21). 

Imagine, now, an opposite extreme : the return wire from the 
rails is made small, or removed altogether, while the return wire 
from the pipes extends over the danger district. You will see 
the current all returns by the pipes and pipe return wire ; the 
current passing at all points from the rails through the earth to 
the pipes, raises the potential of the earth above that of the pipes 
and so assures protection to the latter. 

This is an extreme measure and may never be necessary, but 
should it be found so, as the railway companies cause the trouble, 
it is to be presumed tfiey will be willing by such means, to trans- 
fer the electrolytic action from pipes to the rails. 

Pbof. Houston : — I think one of the most interesting points 


that has been brought forward in this paper to-night, and one 
which has surprised me very much is the exceedingly small po- 
tential difference which the paper states has been necessary to 
effect electrolysis, namely, that a fraction of a volt difference of 
potential between the pipes and the damp earth surrounding' 
them is sufficient to induce the action. It mav be true that 
electrolytic corrosion did occur on portions of the sheath that 
showed a potential difference between the sheath and the ground 
in the vicmity " of never n^ore than half, and usually less than 
a quarter of a volt." But it seems to me that an error was 
clearly made here, of not taking into account the potential dif- 
ference between the cable and the dynamo at work upon the 
lead sheath through the total resistance of the gi'ound. 1 am the 
more readv to believe that there is some error, or misunderstand- 
ing possibly on my part here, for I know that to effect the dis- 
integration of lead electroly tically in . a storage cell, requires a 
potential difference sufficient to electrolyze tne water, namely, 
over two volts. If it be true that tliis small potential difference 
can electrolyze lead, then I would like to know it, for I believe 
that practical application could be made of this in the storage 
battery. I think it is reasonable to suppose that where a frac- 
tion of a volt is discovered between the sheathing of the cable 
and the ground close by, that many times this fraction would 
exist between the sheathing and the ground at the dynamo ter- 
minals. Of course, if actual measurement, as Mr. Farnham has 
said, of one one-hundredth of a volt can produce electrolytic 
corrosion of lead, why there is nothing to be said against actual 
measurement. I should, however, look very carefully at the 
source used, and the method by which the experimenter assured 
himself that he did not actually limit the potential difference to 
the small fraction stated. 

Mr. Farnham : — I might say in reply to this, some of the text- 
books inform us that we cannot produce that action under less 
than 1.4 volt or something like that. But Mr. Lee, the chemist 
of the American Bell company, to whom I referred in the paper, 
made some very careful tests, and I have reason to believe that 
he is a man of sufficient knowledge to perform them accurately, 
and he tells me that he has produced the action easily by .01 
of a volt and less. Now the reference which I made to cables in 
the test, in which it was said that the voltage was usually less than 
one-half volt, sometimes less than one-quarter, I know nothing 
about, except the report that was given to me. I know in 
our own case we make the measurements where cables have been 
corroded, between the cable sheath and the ground, exactly where 
they lay on the ground, by a Weston voltmeter. I know that 
in the case of the experiment which I shgwed you through the 
lantern, where lead was corroded in three weeks' time, we took 
the voltage between the two terminals at the test tube in which 
the lead wires were placed before they were connected, that is, 


without their beine dipped in the water. We took measure- 
ments there every day and found it less than one-half volt. You 
can easily perceive the action that has gone on there. The lead 
wires were immersed in hydrant water without any acid, salt or 
any other condition to induce or help the action — not distilled 
water but such water as we draw from our Boston waterworks. 
So you see it is true that while it does require a volt or more to 
electrolyze or decompose water in the ordinary meaninff, we do 
get the action on lead and iron pipes with very much less pres- 

Dr. Leonard Waldo: — I think this is a very interesting 
paper, and contains a great deal of valuable information. The 
coal miners have had much trouble in keeping their valves from 
disappearing and their pipes from being eaten up, and inasmuch 
as we have been interested in the metallurgy of that sort of 
thing lately, we have looked into the question. In several in- 
stances we have had valves, parts of pumps and similar articles 
sent to us from the depths of the mine, and several gallons 
of the water which was supposed to do the mischief sent alonff 
with them. We boiled the water holding specimens of the metal 
of which the valves were made, and exposed the specimens for 
weeks at a time, with no chemical action at all on the metal 
similar to that used in the valves or in the pipes. When you in- 
sert an iron pipe and connect the two specimens through a volt- 
meter, you will get a very rapid disintegration of one pipe or 
the other, and you get an indication of anywhere from lour to 
six-tenths of a volt. It is my observation that very efficient de- 
terioration of these underground materials of different potential 
takes place with differences under half a volt. There is another 
(Question which has come up in our minds and I have not heard 
it touched upon to-night, but, I think, it is a fundamental question 
in talking about deterioration of metals under electrolytic or 
acid or water action. The lead which our friends use for sheath- 
ing cable is probably over 95 per cent, lead, but it certainly is 
anything but pure lead, and the secondary couples that are 
formed with antimony or the other impurities that the lead con- 
tains when brought in close contact with the acid waters, eyen 
having a very small percentage of acid in them, produce a cor- 
rosion of the surface, which I do not see any way of taking account 
of. The difference between a copper pipe containing a tenth of 
a per cent, of certain impurities and containing one per cent, of 
the same impurity is very great. But it is no greater than that 
which contams none at all, and that which contains one-tenth of 
one per cent. In all these questions, therefore, of rapid dete- 
rioration of pipe and that sort of thing, I think, the most import- 
ant consideration will have to be given to the actual corrosion 
which occurs because of the molecular, chemical and electri- 
cal action which take place between the metal and its own im- 
purities. As to the small voltages existing, and having the effect 


of corroBion, I think any one who has actually made' measures 
on those pipes in position, with and without* the presence of 
electrical action is quite prepared to testify that the smaller volt- 
ace and the corrosion of the pipes are present at the same time ; 
whether the corrosion is wholly due to the action of the current 
on the principal metal alone or not is qnite another question. 

DiL UHAS. E. Emery : — I did not think the subject of the cor- 
rosion of steam and water pipes underground appropriate to this 
discussion, until the last speaker mentioned tne influence of 
various conditions on the rate and nature of corrosion. In that 
connection I will say that it is found in practice that a steam 
pipe covered with a non-conductor, and maintained at a tempera- 
ture of 250° to 300° F. will not corrode underground, whereas 
a hot water return pipe similarly covered and kept at about 212^ 
corrodes very rapidly. The corrosion is external and appears to 
be ordinary rust. A study of the phenomena indicates tliat 
there is a critical temperature where the gases in the soil act 
more intensely than at other temperatures. Apparently ordi- 
nary carbonic acid gas has the most important mfluence. It 
appears, therefore, tliat the temperature should be considered 
in connection with the other influences on corrosion which have 
been mentioned. 


1894,] DISCUSSION m NEW YORK. 227 

[Communicated after adjournment by Prof. Elihu Thomson.] 

Very early in the history of street railways in Boston, I had 
conferences with Mr. F. S. Pearson, of the West End road and 
others, concerning the means to be employed for preventing elec- 
trolytic action on pipes and other metal stnictnres underground. 
Reversing the current at intervals was suggested and tried, but it 
soon became evident that this would only shift the areas of action 
and no restorative effect or plating of corroded metal could be ex- 
pected. It soon became evident that if the current could always be 
made to enter the metal pipes, etc., from the ground, and leave 
them by metallic connections to track or to returns, tl)e protec- 
tive action of the current with the pipes, etc., as cathodes, might 
be beneficial, and as JVIr. Farnham has ably shown in his very 
interesting paper, this is the principle which has given the best 
results in practice. Indeed may we not be justified in expecting 
that in many cases the natural corrosion may be even arrested by 
the nascent hydrogen set freo at the cathode, or by the negative 
polarization of the pipes with respect to earth ? 

Could every line of pipe l)e relied upon as a complete conduc- 
tor without bad joints, the pn^blem of protection would be much 
simplified, but the current in crossing a bad joint in a line of 
pipe will undoubtedly be partly shunted through the earth around 
the resisting joint, and cause corrosi* n to a greater or less extent. 
Again, if in a line of pipe, every joint was of poor conductivity 
there would be very liitle chance of corrosion by electrolysis, as 
the pipe line would not offer any good path for current. 

Earnest endeavors will be made in the present year to prove 
the practicability of continuous rails electrically welded in place. 
In cities this would give a network containing a vast amount of 
metal in the rails, acting as a conductor for the return current. 
Such a track system, or even a track system well bonded, would, 
if worked with a zone system, in which successive zones of trol- 
ley conductor are made positive atid negative respectively, re- 
move all possibility of trouble, but might increase the risk in 
the accidental crossing of wires on the trolley conductors. Another 
system of working which would remove most of the difficulty in 
our cities, would be the employment of potential reducing motor 

fenerators at various points over the area, the high potential side 
eing fed direct from the power station by metallic circuit, and 
with either alternating or continuous currents, as found most ex- 
pedient; while the low potential S'de, 600 volts or less, would go 
to trolley wire and track respectively. In this case the return 
current would never have to travel very far, and the drop on the 
whole system would be much lessened. Copper would be saved 
and the congested districts could be readily supplied with a lower 
potential than the high speed outlying districts. If alternating 
currents were need from the power station to the motor gene- 
rators, the generators in the station could be made of very large 


capacity, gay 5,000 h. p. in a large city, and the motor generators 
could range from 200 to 500 according to the density of traffic, 
etc. I mention these facts to show that avoidance of all electro- 
lytic corrosion is within the capabilities of electrical engineering, 
while still retaining the continnous current hiotors on the cars, 
and the single overhead trolley wire. It is even possible that 
considerable economy of transmission might be secured over the 
direct supply systems as now used. 
Swampdcett, Mass., April 17, 1894. 

[Communicated after Adjournment by Hermann Lemp, Jr.] 

The paper read by Mr. Famham has a great value as it gives 
in a clear and concise manner facts found under every day work- 
ing conditions. Not only can we by its study analyze the vari- 
ous causes producing the deleterious effects of electrolysis, but 
we can follow step by step the means employed and the effects 
produced for combating these evils. 

In the conclusions reached by the author a few vacancies are 
left which it seems are all well worth considering. 

Two principal causes are apparently considered as unavoidable, 
which to me seem to be the contrary. Mr. Vail, in his paper 
before the National Electric Light Association, has taken the same 
ground. They are : 

1st. There should be no ground connection established from 
dynamos at power station, in fact all precautions taken to prevent 
even accidental ones. 

All connection between dynamos and track should be made by 
means of well insulated feeders, such as are used in any properly 
constructed lighting system. 

2nd. The track itself ought to be as nearly as possible €^ne con- 
tinuous rail. 

The leakage currents which are to-day causing all the mischief, 
are mostly due to insufficient carrying capacity of the track, not 
of the rails themselves but of the joints between the rails. When 
copper bonds are used, the unequal expansion of the two metals 
soon produces a loosening of the joint, increased resistance and 
finally complete deterioration. To this is added the electrolytical 
effect between the copper and iron. 

Iron bonds, on the contrary, have to be made so large to be of 
any use, that the vibration of the passing cars loosens them with 
the same result as with copper. In the discussion following Mr. 
Vail's paper, mention was made several times of the electrically 
welded track. 

Having been intimately connected with the experiments carried 
out in Cambridge during last summer and winter, I think a few 
remarks in reference thereto will be interesting at the present 

The tracks experimented upon were all, before any welding 


was done, condemned by the West End Co. The process was, 
therefore, expected to save them. The original method consisted 
in welding two U shaped yokes on either side of the joint through 
the web of rail. Experiments have proven that from 90 to 
110,000 lbs. was the highest tensile strength that could be ob- 
tained on such joints by this device. 

Of the welds made on Main street, Cambridge, about 10 per 
cent, have broken through the winter, leaving quite a number of 
uninterrupted sections of 600 feet and even one of 1,000 feet. It 
was soon discovered that the method of welding first used was 
not guite satisfactory, as it produced a local strain in the rail hj 
heating only the web part of the rail to a welding heat. Experi- 
ments were made at once with a view of welding the rails right 
at th^ joint and extendingover the whole surface of the rail, in- 
cluding rail and foot. By this process a tensile strength of 
279,000 lbs. could be obtained where one of 100.000 only was 
possible before. 

Allowing for maximum variation in temperature experienced 
in our climate, it was found that 150,000 lbs. would be sufficient 
to withstand any strain brought upon the rails through contrac- 
tion and expansion alone. 

The season being already far advanced when these experiments 
were concluded, only a part of the track in Cambridge could be 
provided with the new joints. Every one of these welds stood 
through the winter without a*«bj:eak, with the exception of one 
which broke the day it was made and showed poor workmanship. 
A heavy snow storm setting in at that time prevented its being 

From all the experiments made up to date we can draw the 
following conclusions : 

1st. A continuous rail can be used for electric street rail-car 
practice with absolute safety if an expansion joint is inserted 
every 600 feet. 

2nd. A continuous rail can probahly be used without any ex- 
pansion Joint by using the latest method of welding. 

3rd. The electric conductivity of any joint is as great as the 
rail itself. 

4th. All joints being of the same material and continuous even 
when elastic, will not change by vibration, heating or electrolysis. 

6th. By frequently cross connecting the rails — making up a 
track of electrically welded joints, any trouble from interruption 
in the track can be obviated. 

6th. The resistance of the feeders from track to power-house 
is immaterial aside from economy^ provided the ground in power- 
bouse is taken off. 

In conclusion I will say that Mr. A. J. Moxham, President of 
the Johnson Co., who has, and is carrying out all these experi- 
ments, has such faith in the ultimate success of the electric 
welding of rails that through his instructions three machines will 


shortly be in operation to weld one double track from Marcy 
Avenue, Brooklyn, to Manhattan Beach, a total of 35 miles of 
track, also seven miles in St. Louis, and other orders for this work 
are pending. 

The Chicago Meeting, April 25th, 1894. 

The corresponding meeting of the Institute at Chicago was 
held on April 25th, one week later than the New York meeting, 
owing to tne fact that Mr. Farnham's paper was accompanied by 
a large number of lantern slides, which it was not convenient to 
reproduce for simultaneous use in Chicago. The meeting was 
held as usual at the rooms of the Armour Institute, where Pro- 
fessor Stine kindly gave the use of the necessary lantern, and 
provided other needed apparatus. The meeting was well 
attended, the total number present, including members and 
guests, being more than 60. The meeting was called to order hj 
the Local Honorary Secretary and, upon motion of Mr. B. J. 
Arnold. Lieut. Samuel Rodman, Jr., was appointed Chairman. 

Mr. Farnham's paper was read by Mr. A. V. Abbott, the Chief 
Engineer of the Chicago Telephone Company. A number of 
slides, not included in tne illustrations of the paper itself, were 
placed upon the screen, showing sections of corroded pipe from 
various cities. After the reading of the paper, the discussion 
was opened bv Mr. B. J. Arnold. 

Mr B. J. Arnold : — We all remember the trouble which was 
caused about five or six years ago by the action of the electric 
railway current upon tne telephone wires, through induction, 
which rendered speech almost inaudible over many of the tele- 
phone lines, and created a very general agitation throughout the 
country. The telephone companies, after much ineffectual argu- 
ment with electric railway oflicials, city councils and others, 
finally met the issue squarely, and applied the heroic and effective 
remedy of a complete metallic circuit, which very largely elim- 
inated the trouble. It now seems that after the rival interests 
have satisfactorily settled that subject, that the telephone compa- 
nies have encountered a new difficulty which threatens to be 
much more serious than the former. 

In my judgment this question should be met in a fair spirit by 
the railway companies and some means proposed and adopted 
that will not compel the telephone companies to stand practically 
the entire expense of the necessary changes, as they did in the 
former case. It should be borne in mind also by the railway 
companies that the telephone people are not the only ones who 
will rise up in their wrath against this new trouble, as it is 
equally detrimental to the water mains and the lead pipes of the 
water companies, the gas pipes and other metallic underground 

The subject of electrolytic action of the railway current on 

18W ] 1J18CU88I0N IN CHICAGO. 281 

anderground pipes and conductors is now being agitated in 
almost all cities where railways have been running long enough 
for the destractive effect of tne current to make itself known, 
and it will not be long before we shall hear from it in our own city, 
if the many ordinances now being considered by the Council are 
passed without some stipulations regarding the construction and 
carrying capacity of the rail return circuit of the roads which the 
companies propose to build under these franchises. In my judg- 
ment there is no reason why an electric road cannot be built so 
as to almost effectually prevent the destructive electrolytic action 
that has been pointed out to us to night. 

The original method of constructing the return circuit of the 
electric railways was to join the ends of the rails with No. 4 bond 
wire, depending upon this and the fish plates for whatever 
metallic circuit was necessary, and the earth to make up for the 
lack of metal. 

The idea of the supplementary wire was not contemplated on 
the first roads, but as the small bond wires soon became eaten off 
or broken, they were found inadequate, and a N"o. copper bond 
wire was added to supplement the rails. 

Examination in some cases has shown that the supplementary 
wire has disappeared entirely after a few years' use, which 
resulted in the abandonment of it entirely, and the adoption of 
the larger bond wires between the ends of the rails. It is now 
customary to use a No. wire to bond the rails with,, and depend 
upon the rails alone for the return circuit. I am of the opinion 
that if the rails are supplemented by a system of feeders, so that 
the resistance of it is not greater than that of the out-going cir- 
cuit, and tlie rails joined "with a bond equal in conductivity to 
the rail itself, which is most effectually accomplished by welding 
the rails together electrically, that the entire difficulty caused by 
electrolysis will disappear. The Pennsylvania Eailroad Company 
has had a section of the track with the rails welded together, in 
operation for some months, and on the Baden and St. Louis li. 
R. of St. Louis, rails are now being welded together by electric- 
ity, for use as the return circuit of an electric road, and we shall 
look for the results of this experiment with interest. 

The suggestion made by the author of the paper to attach 
feeders to tne water pipes near the power station is a good one, 
and should be adopted in all cases. 

The suggestion of Professor Thomson of the application of 
motor transformers for the purpose of relieving unequal poten- 
tials seem to be impracticable to construct, as well as difficult to 
look after, as it would necessitate numerous electric motors run- 
ning in various parts of the city, the location of which would 
have to be changed from time to time to correspond to the fluc- 
tuating danger line, and would result in constant expense for 
maintenance as well as a large additional equipment. Tne author 
of the paper states that this has never been tried, and I think it 


is safe to assume that it will not prove practical if it is attempted. 

Mr. A. C. Balch, of Portland, Oregon, in a communication to 
one of the railway papers recently, described the method of 
using the three wire system on the electric railway in that city. 

The trolley is divided into sections of about one thousand feet 
in length, the positive wire of one dynamo being connected to 
one section and the negative of the other dynamo to the adjoining 
section, while the neutral wire is connected to the rails. It will 
be noticed that with this arrangement there is a difference 
of 1,000 volts between the adjoining sections of the trolley wire, 
but as they are thoroughly insulated and the motor cars pjass 
from one section to the other quickly, there seems to be no diffi- 
culty caused by the sudden reversal of the current through the 
motors when passing from one section to another. So long as the 
cars are properly distributed on the line, I see no difficulty 
in the* operation of an electric railway with the three wire 
system, but if the cars were to become " bunched," as sometimes 
happens in large cities, the feeder wire supplying that particular 
section would be overworked, although I do not regard this diffi- 
culty as serious. With this arrangement the electrolytic action 
on pipes is almost, if not entirely, avoided, as there is practically 
no current flowing from the trolley to the earth when the road is 
working under normal conditions. I believe'^there is also a three 
wire electric road in operation in Bangor, Maine, and so far as I 
am able to learn it is working with entire satisfaction. 

There are many who advocate the double overhead trolley 
system, which was used on many of the pioneer electric roads, all 
of which have been abandoned, so far as I know, except one or 
two roads in Cincinnati. The chief difficulty with such a system 
is the complication of the overhead construction, marring the 
appearance of the streets, and difficulty in operation during snow 
and sleet storms. 

If the alternating: motor ever becomes perfected so as to make 
it applicable for electric railroad work, our grief f hom electrol- 
ysis will cease, but unfortunately this millennium seems far 

I have a communication from Mr. Alex Dow, City Elec- 
trician of Detroit, Michigan, who is thoroughly qualified to 
speak on this subject. 1 wish to submit it as a written discus- 
sion from him, as it contains valuable data concerning the con- 
dition of potential differences existing in Detroit, and the result 
of the consideration of the subject before us to-night, reached by 
the municipal engineers of Detroit. 

Detroit, April 23, 1894. 
B. J. Arnold, Esq.. 

Chicago, Illinois. 

I enclose a print of a table of measurements of potential differences between 
the railroad tracks and other underground constructions in this town. 









Observed P 
Max. Min. 



Woodbridge and Antoine 

Water pipe positive 



Observations taken on a 
branch track to car bams 
about 70 feet from Sta- 

Jefferson and Antoine 

Water pipe positive 
Gas pipe positive 






Observations about 350 
feet from Station and 
within 50 feet of connec- 
nection to a return or 
track feeder. Cars pass- 
ing frequently. 

Jefferson and Ranaolph 

Water pipe positive 




Distance from Station 
about 1,405 -feet. Cars 
passing frequently. 

Jefferson and Baldwin 

Rails positive 




DisUnce from Sution 
about 12,900 feet of which 

remainder strap rail. 

Jefferson and Holcombe 

Rails positive 




Distance from Station 
about 17,500 feet of which 
8,850 feet is of TO lb. gir- 
der double track. 

Jefferson and Cadillac 

Rails positive 




End of water pipe sys- 
tem. Distance from Sta- 
tion about 4 miles, track 
continued 3 miles fur- 
ther, single track 60 lb. 
- T " rail. 

Elmwood and Mack 

Rails positive 




Straight line from end of 
track to Station 11,000 
feet; no return or track 
feeder; single track. 
Strap rails, ^2 in. water 
main parallel to tracks. 
P. D. small until cars 
come on particular rail 
to which wire was at- 

Woodward a d Canfield 

Rail positive 




Distance from Station 
about io,2co feet, 70 lbs. 
girder rails. 

Champlatn and Seyburn 

" " 




Distance from Station 6 

CharapUinand Mt. Eiliot 

i( II 




Distance from Station 5 

The tests were made by a oommittee of the Municipal Engineers* Association 
-with the view of learning the actual state of affairs, and particularly in view of 
street railway legislation now before the City Council. We desired to know the 
results obtained with the present street railway constructions, and, if it ap- 
peared necessary, to ask for protective clauses in the street railway ordinances. 

The Association has not yet acted upon the committee's report, but the opin- 
ion of the members seerns to be in favor of requiring the street railway company 
to put in a complete return circuit of such efficiency that there will be no appre- 
ciable tendency to leakage to the water pipes, underground cables, etc., for 
which we municipal engineers are responsible. 


We admit the theoretical possibility of connecting our constructions with the 
street car return and with the negative pole of the dynamo so as to maintain a 
uniform earth potential all over the city ; but we conclude, after consideration 
of the different depths at which our various pipes, etc. are laid in the soil, of 
the different ages and characters of the said pipes, etc., and of the varied nature 
of the soil itself, that carrying out the theory into practice will be very difficult; 
so that we are minded to ask for restrictions as to the potential difference per- 
missible between the rails and neighboring underground constructions such as 
we want to protect. We don't entirely believe that this difference of potential 
is a measure of the risk of injury by electrolysis, Imt we are positive that when 
the potential difference is inappreciable the return circuit of the railroad com- 
pany is sufficient for the work put upon it, and our pipes are not being called on 
to assist it to any dangerous extent. 

Alex Dow, City Electrician. 

I am sure that we have all been very much benefited by the 
reading of Mr. Farnham's paper and the excellent manner in 
which Mr. Abbott has presented it to us this evening, and I hop© 
that it will result in a thorough discussion by the members 

Mr. Welles of the Western Electric Company, whose name 
was mentioned by Mr. Farnham in his paper, was present and 
was asked to contribute to the discussion. Mr. Welles in reply 
said : 

Mr. a. T. Welles: — Not being a member of the Institute I 
came here with no idea of being called upon to speak, but as Mr. 
Farnham has quoted me as saying that " in examining the first 
cases in Cincinnati " I found never more than one-half volt and 
generally less than one-quarter volt current on the underground 
cables there, I wish to say that Mr. Farnham has unintentionally 
misquoted me, as was also the care in the interview in a Cincinnati 
paper which brought about my correspondence with him. The 
statement would lead you to suppose that some electroly tical trouble 
had developed in cables laid by my company in Cincinnati, but 
this is not the case as far as I know. 

In December last a cable which we had laid in Louisville less 
than a year ago for the Ohio Valley Telephone Co. began to give 
out. We sent a cable splicer there and he located the trouble in 
two sections of several hundred feet each, near one of the power- 
houses of the electric street railway. About Christmas, Captain 
Gifford telegraphed my company requesting that Mr. I^atterson 
or myself should come at once to investigate the cause of the 
troulile, and I was sent. I found that the two sections had been 
partially pulled out of the conduit and in examining the pieces 
cut off, found that holes were partially or wholly eaten through 
the lead covering at regular intervals. These holes occurred 
every 18 inches and corresponded exactly with the joints of the 
vitrified clay conduit. 

With Mr. Maxwell, the electrician of the telephone company, 
I made a number of potential tests in the manholes near the 

1894.] DI8CVS8I0N IN CHICAQO. 285 

{Jace of the trouble and found as high as two and one-half volts 
rom the cable to the rail of the trofley road. In these manholes 
there were also gas and water pipes which had about the same 
voltage as the cable. I also made 40 or 50 tests across the joints 
of the rails with a voltmeter reading down to one-tenth and I 
think we could have noticed one one-hundreth of a volt, but 
there was not the slightest movement of the needle. 

These tests were reported to Captain Gifford, who then called 
in the electrician of the street railway. This gentleman ex- 
plained that besides having the rails perfectly bonded at their 
joints, they had two return wires of No. or larger copper run 
underneath the rails and bonded to them at frequent intervals. 

In Louisville the underground telephone cables run from all 
points of the compass into the company's oiBce. These cables, 
some 30 in number, are practically bunched at or near the ex- 
change, so that any currents coming in on their sheaths can, 
without trouble, reach those of such cables as will most readily 
return them to the power-houses. All of these cables run par- 
allel with trolley lines or with gas or water mains which parallel 
the trolley, so that each carries to the common point more or less 
current. Taken singly, these currents are slight and would prob- 
ably cause no trouble ior a long time at least, but one-half or 
two-thirds of their total was sufficient to eat through the pipe of 
tlie cable in trouble in seven or eight months. At present there 
are but two cables which run from the exchange to points near 
power-houses. One of these nms to a point within a block or so 
of a power-house about two miles from the exchange in one di- 
rection, and the other to within three blocks of a power-house in 
the opposite direction. The first one giving the best return and 
also running for a long distance parallel witli a trolley line and 
water mains, where it picked up additional current is the one 
which gave out. Preventions which we used will, I suppose, 
save the other. From Louisville I went to Cincinnati where we 
had laid a large quantity of cable for the City and Suburban 
Telegraph Association. Here, with Mr. Robinson, their super- 
intendent of construction, I made a large number of voltmeter 
tests between the cables and the trolley-road rails in different 
parts of the city, and found at no point more than one-half volt 
current in either direction. These tests led to the interview pre- 
viously mentioned. Some weeks later Mr. Faruhaln wrote me 
that he had read an " interesting " interview with me in a Cin- 
cinnati paper and asked me for data on the subject of electrolysis. 
As the mterview as published is rather " interesting " in some 
respects, I will read it if you will allow me. 

[Mr. Welles read the article and proceeded as follows :] 

I simply wish to make one other statement. Since Mr. Farn- 
ham collected the data for his paper, we have run across another 
very peculiar case of electrolysis in Cleveland. A cable which 
my company laid there in January last for the Postal Telegraph 


Co. was reported ae liaving given out entirely about two weeks 
affo. The cable ran from their olRce down about 1,500 feet and 
then through a tunnel about 80 feet deep under the river to a 
pole on the opposite side near a manhole at the mouth of the 
tunnel. Through this tunnel a large water main also runs. We 
sent a splicer there at once and he located the trouble in this 
manhole where he found the cable pipe entirely eaten through. 

Mr. L. L. Summers, of the Postal Company, made voltmeter 
and ammeter tests at this place and found 18 or 19 volts on the 
cable, and also on the wat«r main in the tunnel and 45 amperes 
current. The cable pipe was eaten through in ten weeks. What 
is going to become ot that water main, and what is going to be- 
come of that tunnel 1 

Pbof. W. M. Stine : — I would like to ask Mr. Welles what 
conditions he found where they were using the double trolley in 

Mr. Welles : — My tests were made on New Year's Day, 
which was particularly dry and clear. This probably accounted 
for the very low potentials found on the cables. On. account of 
the intricate system of water and gas mains running close to the 
conduits, and often through the manholes, it is impossible to say 
whether the leakages came from the single trolley or the double 
trolley system. We found current on cables wliich, in no part 
of their circuit, paralleled either system. I was told, however, 
that in rainy weather much trouble is experienced by the tele- 
phone company on account of the splashing of mud against the 
car motors of the double trolley system, which often brings 
down 200 or more drops at a time in the switchboard. But this, 
I should think, is simply a matter of construction of the motors. 

Professor D. C Jackson of the University of Wisconsin had 
sent in the following contribution to the discussion which was 
read by the secretary. 

[Communicated by Paul Biefeld and Fred. D. Silber.J 

Having made an extended series of experiments relating to the 
subject of Mr. Farnham's paper, we desire to present some of 
the results of our investigation as carried on in the laboratories 
of the University of Wisconsin, and along the line of the electric 
railway of Madison, Wisconsin, under the direction of Professor 
Dugald C. Jackson. 

This railway line has been in operation for about a year and a 
half, having nine cars in service, but no troubles due to corro- 
sion have shown themselves thus far. Measui'cments of potential 
between water pipes and rails, near power station, show a diiler- 
ence of 4^ to 5|^ volts, water pipe being positive to rail, and 2^ 
to 3i volts between water pipe and the earth near the rail, water 
pipe being positive to earth. The potential revei*sed at a dis- 
tance of from 1,600 to 1,800 feet trom the station, the range 


being zero to four volts outside of this neutral zone, the water 
pipes being negative to rails and eartli. Samples of soil were 
taKen from pomts along the line, and subiected to electrolysis 
between iron plates, when the anode showed a loss ranging from 
.7 to 1.15 grams per ampere hour, the cathode remaining un- 

Experiments are at present in progress to determine the actual 
current flowing between pipe and rau. This is done by means of 
a modified form of a copper voltameter devised for this purpose. 
A water-tight box containing a solution of copper sulphate is 
buried in the ground. This box Jias for two of its opposite sides, 
facing the pipe and rail respectively, double copper plates, of 
which the inside ones are weighed. The gain of cathode will 
then give in the usual way an integral measure of the current. 
The slmnting effect of the voltameter of low resistance, will in- 
troduce only a small error, as the distance between pipe and rail 
is comparatively great. Having thus found the average current 
flowing, and knowing the loss of anode per ampere hour, a fair 
estimate can be made of the loss of metal from the pipe per 

A series of experiments to determine the minimum potential 
at which corrosion may go on between iron plates, showed that a 
mere directive force was needed ; the potential having been re- 
duced to .001 of a volt, electrolytic action still went on. In each 
case the action was manifested by the formation of a ferrous salt 
at the anode, and the hydroxide of the alkaline metal at the 
cathode. This phenomenon shows at once the cause of the cor- 
rosion. The main object of our investigation has indeed been 
to determine exactly what goes on in an electrolytic cell under 
parallel conditions to those lound in practice. 

Whenever iron electrodes were used with soil or sand contain- 
ing small quantities of soluble salts in solution, a layer of ferrous 
hydroxide was invariably formed at some point between the two 
plates. The earth used was found to contain small quantities of 
chlorides and sulphates of the alkaline metals, and showed no 
trace of soluble iron salts or alkaline action, before electrolysis. 
After the current was put on, ferrous salt began to be formed at 
the anode spreading toward the cathode ; the hydroxide of the 
alkaline metal was formed at the cathode spreading toward the 
anode ; where the two met, a layer of ferrous hydroxide was 
precipitated, recognized at once by its dirty green color. 

In all these cells a peculiar heating effect was noticed, reach- 
ing a maximum in the ferrous hydroxide layer, and diminishing 
in general toward the electrodes. Measurements of potentitS 
taken within the cell at different points between the plates 
showed the greatest difference of potential at the zone of maxi- 
mum temperature, and a diminishing difference in the same way 
as the thermometer had shown a fall in temperature. It must 
be stated here that the readings of potential were taken when 


no appreciable heating effect was noticed, only a very small and 
constant current flowing at that time. These "observations show 
that the unequal heating was caused by unequal resistances in 
different parts of the cell due to the formation of the hydroxide 
layer, together with the unequal concentration of the iron salt 
and the alkaline hydroxide, which diffuse toward the point where 
the precipitate of iron hydroxide is formed. 

A similar variation of temperature, only much less marked, 
showed itself in a cell containing pure sand (practically free 
from soluble salts) and distilled water. The platinum electrodes 
were six cm. apart, 500 volts were used and a current of one am- 
pere sent through. Oxygen and hydrogen were given off at the 
positive and negative poles respectively, as secondary products of 
the acid which was formed at the former, and of the hydroxide 
which was formed at the latter pole. There was no electrolysis 
of water, as seems to be still lield by some. Although the elec- 
trolyte was thought to be free from soluble salts, tne tempera- 
ture effect was still present, and was caused by the diffusion and 
consequent unequal concentration of the acid and hydroxide to- 
ward a point between the two plates where the zone of maximum 
temperature showed itself. This is to be expected since the con- 
ductivity of acids and alkaline hydroxides varies within certain 
limits directly as their concentrations. 

The theory has been put forth that the corrosion is due to the 
electrolysis of water ; the nascent oxygen attacking the iron at 
the positive pole. In the first place, tnere is no electrolysis of 
water ; oxygen and hydrogen being in each case set free at their 
proper poles by virtue of secondary reactions, as explained above. 
The fact, however, that nascent oxygen even then does not attack 
the anode when the iron electrodes are used, is clearly pointed 
out by an experiment, wherein six such cells were run in series at 
100 volts terminal pressure, the current varying from .2 to .04 am- 
peres during the experiment. The electrolytes consisted of pure 
glass sand saturated with a one-third of one per cent, solution of 
chemically pure nitrate of ammonia, chloride of ammonia, 
nitrate of potash, chloride of potash, nitrate of soda, and chlo- 
ride of soda respectively. All nitrate cells showed acid reactions 
at the an6de, and gave off oxygen at the same pole, and hydro- 
gen as usual at the cathode. At .06 amperes, tiie acid reaction 
and oxygen evolution ceased, in the cell containing nitrate of am- 
monia ; at .045 tlie same occurred in the cell containing nitrate 
of potash, the cell containing nitrate of soda still showing a faint 
acid reaction, and giving off of oxygen at .04 amperes, at which 
point the current was taken off. Tne chloride cells showed no 
such phenomena at tlie anode. The following table gives the 
corresponding losses of the different anodes per ampere hour, 
the cathodes remaining unchanged : 

18W.] • DISCUSSION IN CHIC A 00. 289 

NH4 NO, 0.921 gms. loss. 

NH4CI 1.314 '* *' 

KNO3 0.887 ** *' 

KCl 1.846 " '* 

NaNO, 0.729 ** '* 

NaCl 1.299 '* " 

It will be noticed that the loss iii the chloride cells is consider- 
ably greater than that in the nitrate cells ; the acid and oxygen 
formation in the latter having evidently not assisted in the cor- 
rosion of the anode. Furthermore, had the nascent oxygen at- 
tacked the iron, ferrous oxide, (Fe O) would have been the result, 
which, in presence of water forms ferrous hydroxide (Fe O + 
H2 O = Fe (0H)2). This ferrous hydroxide would have showed 
itself next to the anode ; no such layer, however, appeared in 
that region. Moreover in most cases where pipes nave been 
pitted, the "secondary products seemed to have been carried 

Tne real facts and explanation are given in the following con- 
clusions : In an electrolytic cell with iron electrodes, having any 
salt or salts of the alkaline metals or earths in solution in the 
electrolyte, the salts are electrolyzed ; their acid radicals (CI, 
NOs, SO4, etc.), attacking the anode, forming an iron salt. The 
metal set free at the cathode forms with water the hydroxide 
and liberates hydrogen. The ferrous salt diffuses toward the 
cathode, the alkaline hydroxide toward the anode, and at the 
point of meeting the ferrous hydroxide is precipitated and the 
original salt reformed. As the amount of electrolysis varies 
directly with the strength of current, a comparatively high cur- 
rent will liberate an excess of the acid radical ; the critical point 
depending on the affinity of the radical for the iron, the surface 
exposed being the same. This excess forms in the presence of 
water an acid, and liberates oxygen. 

Neither the acid nor the oxygen have any effect on the iron, 
the anode being already engaged in the formation of the iron 
salt with the acid radical ; nence, the oxygen escapes, and the 
acid diffuses through the electrolyte. Many important physical 
and chemical questions arise at this point ; these, however, can- 
not be considered here. 

The last experiment, together with the fact that the ferrous 
hydroxide layer invariably forms at some distance away from 
the anode, points very strongly to the conclusion that the corro- 
sion is solely due to the attack of the dcid radical of the salt 
crigitiaUy in the electrolyte. As cnlorides, sulphates and nitrates 
of the alkaline metals and earths are almost invariably found in 
street solids, and as a mere directive force in the way of an 
electric pressure is required to set up an electrolysis of these 
salts, it can be plainly seen that the iron pipes may be corroded 
wherever the potential at the latter is positive to the rail. The 
amount of corrosion in a given time only depends upon the 
amount of the current and me nature of the salts in the soil. 


Our investigations lead us to indorse Mr. Famliam's method 
of preventing the corrosion, and the following points in his sum- 
mary we desire to particularly emphasize : 

1." A return circuit of as low resistance as possible. 

2. A positive pole of the generator connected with the 

3. Careful location of the danger district and thorough con- 
nections between pipe and rail inside of this district ; the rails 
to be connected to tlie negative pole of the dynamo. 

4. Frequent measurements to be made to see that the danger 
district does not change, and no connections to be made outside 
of the district. 

Mftdison, Wis., April 28, 1894. 

Mr. C. G. Armstrong : — I cannot help but feel that we are guilty 
as charged in this indictment, that we cannot have a great good 
without some small damage, and to offset the manifola blessings 
and benefits of the commercial use of powerful currents of elec- 
tricity, we undoubtedly do some damage to other and adjacent 

Some years ago I was requested to inspect an electric railroad 
in Indiana, where I had some experience with the erratic action 
of electricity under ground, ana where I made some measure- 
ments of differences in potential between adjacent conductors. 
Unlike Mr. Farnham I did not use a voltmeter, but used a mule: 
that is to say, the owners had noticed a variation in the opera- 
tion and speed of their motors at a certain point. I watched a 
mule team driven over this place and found that at a certain 
point one of the mules became very much agitated, to the extent 
of planting his hind feet on the dashboard of the wagon many 
times in rapid succession. I had no means of calibrating the 
mule, but would judge that the potential difference must nave 
been considerable at tnis point, and upon inspection I found that 
the rail bonds were broken, and a very disagreeable shock could 
be felt by touching the ends of the rails at this point. 

The construction of this plant had been very unscientific and 
extreme differences of potential could be found in different parts 
of the town, but being only a country village with few pipes and 
fewer scientists, the matter of destruction to anything except the 
railroad property itself by reason of this faulty work was not 
thought of. 

Wherever we have a flow of current through the earth, owing 
to its irregular conductivity, we are bound to have differences in 
potential, and where we have differences in potential, electrolysis 
and chemical decom position will occur. Even if this difference ia 
extremely slight we will have some destructive action; at the same 
time 1 doubt whether we can have any serious destruction with- 
out we have one and one-half volts, or sufficient to decompose 
the moisture, liberating the oxygen which in its nascent state, to 

18M ] DJ8CUS810K IN CHICAGO. 241 

my mind, is the most destructive agent produced by electrolysis. 

I cannot feel that electrolysis is ^ilty of all things charged to 
it. I do not believe that everv defective water pipe and gas 
main was destroyed by electricity. I have seen miles of water 
and gas pipe that was in much worse condition than that shown 
on the screen to-night, where the nearest electric wire was twenty 
miles away. I believe the gas companies are r esp onsible for two- 
thirds of the trouble found in pipes to-day. Where we dig up 
the streets we tind the earth permeated with ammonia and other 
destructive products of the gas retort, which within themselves 
are sufficient to attack and decompose any metal they come in 
contact with ; in fact, one of the pipes shown on the screen was 
a gas pipe, and there was a serious decomposition of the metal 
on eacn side of the union. The author of the paper attributes 
this to the resistance of the union; why might it not have been 
the leakage of the gas? I have found gas pipes that could not 
possibly be acted upon by electricity that were decomposed in 
exactly the same manner, from the gradual leakage of the gas. 

Undoubtedly we are guilty to a certain extent for the destruc- 
tion of underground pipes, and the cause I believe can be re- 
moved. The use of the three wire system as mentioned by Mr. 
Arnold is undoubtedly one solution, but ofiEers complications as 
he mentioned. The use of the return wire as suggested in the 
paper is another remedy, but one which I am afraid will greatly 
interfere with the "returns" at the meeting of the stockholders. 

As mentioned in the paper, every additional pipe protected,, 
reduces your protection to all others and to obtain absolute pro- 
tection, it would be necessaiy to literally fill the ground with 
copper wire, and have the different resistances nicely and mathe- 
matically balanced, and even then with a large number of cars at 
the extreme end of the line, the resistance might be thrown out 
of balance and electrolytic action result therefrom. 

I think this problem should be viewed just as we do the 
wiring of a building, viz., avoid grounded circuits, insulate both 
poles and thereby dispense with electrolysis, danger from IBire, 
and at once solve the difficult problem of lightning arresters for 
grounded circuits. 

There seems to be no practical difficulty in the use of the two 
trolleys. They are running in many places to-day with a fair 
degree of success and I believe if it had not been for the violent 
opposition of one of the large companies, as suggested here to- 
night, it would have been used much more extensively than the 
single trolley. I really do not see after all why it is not the best 
way out of the present difficulty. It certainly would not cost as 
much to run a double trolley system as it would to run a com- 
plicated system of underground returns connecting to all water, 
gas and other pipes and what not that we meet in the street. 
The system advocated by Mr. Stetson, of an underground 
double trolley, or a similar system with his catch box elevated on 


posts between the tracks, would afford another method of accom- 
plishing the same end. 

If electrical engineers would lay aside the creeds laid down by 
their various commercial interests and attack the problem from a 
purely scientific standpoint, following out the practice of electric 
light engineers, viz., insulate both poles from the ground, the ques- 
tion of electrolysis would be solved just as the metallic circuit 
has solved many more serious problems in telephony. 

Brief remarks were made by Professor Stine, Mr. Beach and 
Mr. A. S. Hibbard. 

Mr. Abbott closed the discussion on behalf of the author of the 
paper, as follows: 

Mb. a. V. Abbott : — A previous speaker has alluded to the 
use of the double trolley system, as offering a solution of the 
electrolytic question. 

The double trolley system certainly does afford a perfect solu- 
tion, but only at the expense of a greater investment of capital 
in the original line construction, as the amount of copper re- 
quired for a double trolley system over that needed with the 
single wire would be increased about fourfold, and as much com- 
plexity would be involved in the erection of the wiring. The 
objections to the double trolley system, other than those of in- 
creased capitalization, are entirely mechanical ones and in ordi- 
nary lines can be overcome. The double trolley, about three 
years ago still survived, and it is probably chiefly due to the 
Thomson-Houston company that it does not still exist. 

In all railways whicn are reasonably straight, and do not en- 
counter a great number of intersecting lines, the introduction of 
the double trolley is not a serious obstacle, and by affording to 
the street railway an independent retura, places the railway cir- 
cuit entirely under control of the railway managers, pre>enting 
to the company in this respect considerable advantage. It is 
probable, nay, almost certain, that should street railway companies 
be obliged to protect all present existing underground struc- 
tures by means of special return feeds, as indicated by Mr. 
Farnham, the expense of these feeds, and their introduction 
would be considerably less than the original cost required to 
equip the line with a double trolley system. 

Personally, I have always been m favor of all electrical com- 
panies operating entirely upon metallic circuits which should be 
peculiarly and appropriately their own. I think the advantages- 
to be derived from* this principle of operation will, sooner or 
later, be appreciated, and that street railway companies, electric 
lighting companies, telephone corporations, in fact, all electri- 
cS industries will, in the not far distant future, be each equipped 
-with its own individual and independent complete circuit. 

The presence of overhead wires in the crowded city streets, is 
constantly urged as an objection to the trolley system, whether 


it be single or double. Inventors have been constantly called 
upon to devise methods whereby the streets could be relieved 
from this objection. 

A conduit electric road is at the present time perfectly feas- 
ible, and its successful construction and operation is merely a 
question of the amount of capital that the promoters are willing 
to invest Ordinarily speaking, an electric road can be built 
and equipped in running order at an expense of from thirty to 
forty thousand dollars per mile including all items, excepting 
that of real estate, franchises and buildings. The cable road is 
typical of the conduit system, and is always expected to cost 
from one hundred twenty-five, to one hundred fifty thousand 
dollars a mile. The widespread and rapid introduction of elec- 
tric roads has chiefly resulted from the fact that they require so 
much smaller capitalization in the outset, and that they, there- 
fore, may be introduced in districts that are not thickly settled, 
in which the traflSc could never be made to pay the interest and 
depreciation on the more expensive cable plant. Cable roads 
could never, for a moment, be considered, in many of the dis- 
tricts where electrical roads are now successfully and remunera- 
tively operating, having superseded animal traction. 

If a street railway company is willing to invest in an electric 
road the same amount of capital as is called for by the ordinary 
<3able road, a successful conduit system can be at once introducedf. 
The success of the conduit electrical road simply depending 
upon its being built well enough to do the work required of it. 

In a consideration of the return system for an electric road, 
the railway company should not forget, that by providing an 
adequate return circuit which will protect other underground 
structures, they are not only securing immunity for themselves 
from damage suits, but at the same time are putting more money 
into their pockets in a saving of coal pile, than the interest and 
the depreciation upon the investment mvolved in the return cir- 
-cuit willamount to. 

In building some 300 miles of electric road I have universally 
found that the grounded return circuit absorbed more energy 
from the station than any other part of the line, the car motor 
only excepted. In one instance in mind, the return circuit of 
the road was so poor, owing to defective rail bonding and the 
dry condition of the soil that, in many instances, the rail bonds 
had actually burned their way through the ties of the road and 
allowed the rails to separate. 

In another instance, motor repairs were reduced several hun- 
dred dollars a month by the addition of an appropriate amount 
of feed wire. 

Ill a third case, the amount of power required for operation 
was reduced toSOn. p., bv the provision of an appropriate return. 

I feel quite confident that, if the engineers of the majority of 
■electric railways in this country would carefully study their cir- 


cuits, making accurate measurements thereon, they would be 
immediately convinced that the expenditure required for an ap- 
propriate return circuit which could in a majority of instances be 
arranged to protect existing underground structures, would re- 
sult in an actual saving to them in luel, and would be an invest- 
ment upon which they could immediately enter. 

After the discussion was closed it was moved by Edward 
Caldwell, and upon motion it was carried, '"that it is the opinion 
of the western members of the American Institute of Electrical 
Engineers that the expenses incurred in connection with the local 
meetings held in Chicago should be paid out of the general funds 
of the Institute, and that a committee of three, of which Mr. 
Hibbard shall be chairman, be appointed to brinjj: this matter to 
the attention of the Institute at the Annual Meetmg in Philadel- 

f)hia next month for the purpose of securing, if possible, such 
egislation as will make the general funds available for this pur- 

The meeting then adjourned, leaving the other members of 
the committee to be appointed later. 

[Reply to the Chicago Discussion, Communicated by Mr. 


I have read with a great deal of interest the able discussion in 
Chicago which followed the reading of my recent paper. The 
work of Professor Jackson and his assistants is of special service, 
as it ought to entirely dispose of the doubt heretofore existing 
in many minds, that currents produced by small differences in 
potential are sufficient, and actually do cause corrosion of metal 
Duried in the earth. I hope readers of this j)aper will not pass 
too lightly over this fact. If we appreciate the danger as it ex- 
ists, we shall be more likely to apply a sufficient remedy, and we 
shall look for the danger m important places which otherwise 
may escape detection until too late to controvert serious lose. 
The Chicago discussion calls attention to serious effects of elec- 
trolysis upon metal lined imderground tunnels. How may it be 
with anchorages to suspension oridges, and to the iron feet of 
elevated railway structures, especially those employed to carry in 
a measure the heavy currents of the railway ? ^ 

Referring to Mr. A. T. Welles' remarks. I did accidentally 
confuse Cincinnati with Cleveland. 

It was unfortunate, as Cincinnati having a good example of 
the double trolley system might be expected to escape the trouble 
from electrolysis. This expectation would undoubtedly be rea- 
lized but for the fact that there is also in the city a small electric 
railway system employing the single trolley. 

1. The most powerful and important agents in nature are. slow in their opera- 


I have but little criticism to offer upon the discussion. I agree 
entirely with all that has been said, both in New York and Chi- 
cago, as to the importance of large railway returns and thorough 
bonding of rails. Mind you, I do not say " ample " railway re- 
turns, tor returns ample to prevent escape of current to the earth 
and adjacent pipes cannot practicallv be provided. 

I am in hearty accord also with the able remarks of Mr. Ab- 
bott and others with reference to the employment of the " double 
trolley system," or in fact any system wliich maintains the entire 
circuit well insulated frotn the earth. My paper implies this, and 
to this end I have written several articles in the early days of 
the railway ventures. 

I do not agree that it is as well to connect pipes to the rails 
within the danger zone or area as to employ a special return wire, 
for relieving them. A careful study oi the situation which may 
be met in large cities will make it clear that not only must the 
pipes have good conductors back to the dynamo, but that tlie 
potential of the earth about them must in some cases be raised 
above the normal condition ; this can be accomplished in no way 
easier than by so proportioning the return system of the rails and 
the pipes as to cause a small passage of current from rails to 
pipes through the earth, within the danger territory. 

^or do I agree with Mr. Armstrong, that the ground may 
have to be filled with copper to accomplish the remedy if applied 
as I recommend. A carefurpernsal of the paper itself, and the 
New York discussion will malce it unnecessary to explain further 
why a comparatively small amount of copper properly placed 
in the danger area will transfer the damaging action :from the 
pipes to the railway system itself. 

I must note again in closing, my ^reat satisfaction with the 
handling of the paper and the discussion at Chicago, and I wish 
to express my personal thanks to all who have aided me in the 
i)reparation and presentation, of this paper, and to others who 
have added so much of interest and value by the discussions. 
Boston, May 9, 1894. 


Annual Meeting. 

Philadelphia, Pa., May 15, 1894. 

The Annual Meeting of the Institute was called to order at 
10.30 A.M. on Tuesday, May 15th, at the house of the Engineers' 
Club, 1122 Girard Street, by the President of the Institute, 
Professor Edwin J. Houston. 

It was voted that the reading of the minutes of the previous 
annual meeting be dispensed with, and, on motion, they were 
approved as printed in the Transactions. 

The President: — Before proceeding to the next order of 
business, which will be the report of the Council, the duty of 
the meeting is to appoint tellers. The rules call for two tellers. 
Will some gentleman make a nomination? 

Messrs. Metcalfe and Upton being nominated, they were ap- 
pointed by the President as tellers. 

Mayor Stewart, of Philadelphia, was then introduced by the 
President, who welcomed the Institute to the city, with appro- 
priate remarks. 

The President : — Mr. Mayor, I desire to express, on behalf 
of the Amkrican Institute of Electrical Engineers, the body 
I have the honor of presiding over at the present time, their 
thanks for the warm and cordial manner in which you have wel- 
comed us to the city of Philadelphia, for the flattering things 
you have said about us, and for the kind invitation you have 
given us. I assure your honor, that we shall hold this meeting 
m Philadelphia in pleasant remembrance. 

Mr. John C. Trautwine, Jr., President of the Engineers* 
Club, of Philadelphia, upon invitation, addressed the meeting as 
follows : —I trust that I may be able to give expresaion to the 
sincere pleasure it affords me to bid you, in the name of our 
club, a hearty welcome to our house, where I trust that you will 
be able to make yourselves comfortable during your brief stay in 
our city. 246 


Oar club, as muBt almost of neceBsity be the case in a local 
engineering organization, numbers among its members engineers 
of all branches of the profession, and among these are many 
worthy and active representatives of your own branch, and mem- 
bers of your Institute. 

His honor, the mayor, has already pointed out to you the fit- 
ness of selecting, as the place for holding your tenth annual 
convention, the city of Franklin's electrical researches, the city 
where his remains were laid to rest. But Philadelphia claims 
also the honor of being the birthplace of your still young, and 
already vigorous, organization, and in this way we see another 
claim to your attention. 

I congratulate you upon the excellent weather which your 
local committee has selected for the occasion, and I trust that 
your stay with us may be in every way enjoyable. 

The following reports of the Council and Treasurer were then 

Report of Council for the Year ending April 30th, 1894. 

In compliance with the rules of the Institute your Council begs leave to 
submit the following report covering the period since the Annual Meeting, 
May i6th, 1893. 

Ten regular meetings and one special meeting of the Council have been 
held at which the average attendance was 9. 

As stated in the report of last year, there has been a desire manifested 
by the membership for the adoption by the Institute of an official badge, 
and a certificate of membership. Many designs were submitted and the 
matter was given careful attention by a special committee. Both the 
badge and certificate were prepared for distribution about the date of the 
last annual meering. Your Council has also instructed the Secretary to print 
upon all publications of the Institute the emblem thus officially adopted. 

In view of the probability of a large number of visitors at the World's Fair 
and Electrical Congress, who would be glad to avail themselves of office 
facilities, your Council recognized the necessity of establishing at the 
Electricity Building, a suitable rendezvous, which was placed under the 
direct charge of the Secretary. As no fund existed which could be properly 
drawn upon for this object, it became necessary to issue a call for voluntary 
subscriptions for this purpose. There was a general and hearty approval 
of the plan and as will be seen by the financial report, the receipts were 
$1,148.14. This amount was not quite sufficient to cover the entire ex- 
penses which were $1,331,047, leaving a deficit of $183.33. ^^^ beneficial 
results accruing from the carrying out of the plan under the supervision of 
the special World's Fair Committee may be learned from their final report 
submitted February 21, 1894, from which the following is an extract. 

" The wisdom of establishing, official headquarters at the World's Fair 
*' has been conclusively proven, and your Committee believes that the In- 
* ' stitute may well congratulate itself upon the results achieved. The Institute 

248 ANNUAL MEETING. [May 15, 

** register shows the memorandum of 612 visitors, among whom were many 
'* of the most distinguished electricians of the day. Eighty-one new asso- 
*' date members have been elected this season ; 15 come up for election on 
" January 17th, and 21 are posted for the February meeting. A total of 
*' 117. Although but few meetings have been held this season, this num- 
*' ber is already in excess of the increase in membership during the entire 
** years of i8gr and 1892. A large proportion of this increase can be traced 
** directly to the World's Fair headquarters, and without doubt our member- 
** ship will continue to be largely augmented by the addition of many of 
*• those identified with the electrical profession who have been led to ap- 
*' preciate the importance of the Institute through information received 
" at the official headquarters at Chicago.'* 

It may also be stated that the expense of maintaining independent offices 
was less than would have been necessary had the Institute joined in the 
maintenance of the general engineering headquarters at Chicago which 
would have required an assessment of $2 j)er member, or a total expendi- 
ture of $1,380, with far inferior results. 

The record of the preliminary work of the Institute in preparing for the 
International Electrical Congress of 1893 has been very fully placed before 
the membership in the printed Transactions, and it is satisfactoi^ to know 
that it was generally appreciated, especially in the deliberations of the 
Chamber of Delegates. In order to provide for the publication of the pro- 
ceedings of the Congress, an arrangement was entered into between the 
regularly appointed Publication Committee and your Council, by which the 
Institute has undertaken to secure a sufficient number of subscriptions to 
guarantee the publication of the Congress records without loss. The limit 
of 400 subscribers having been reached, the work has been started and it is 
expected that the book will be issued by September next. Should any surplus 
accrue from this undertaking, it has been recommended by the World's 
Fair Committee that it be applied to cover the deficit in the World's Fair 
fund as stated. Owing to the lack of time, several matters were left un- 
finished by the Congress, some of which were deemed of such importance 
that a committee has been appointed of which the President is Chairman, 
to carry on the necessary investigations and report upon a standard of 
illumination. This matter, which was considered the most important item 
of incompleted work, is in the hands of various sub-committees, having 
laboratory facilities at their disposal in various parts of the country, and is 
under the direct supervision of members of the Institute. 

The plan of printing and distributing to the entire membership the ad- 
vance copies of the papers read before the Institute meetings, has been 
carried out as thoroughly as possible during the year. The distribution of 
the revised papers with their discussions at the end of the year in a bound 
volume, has been generally appreciated, and while this plan has added 
somewhat to the cost of publication, the total expense incurred was less than 
for the volume of Transactions issued for the previous year. 

Among other results of the World's Fair year, the increase of member- 
ship in Chicago and vicinity, led to a desire upon the part of western mem- 
bers for an opportunity to discuss the various papers brought before the 
Institute. At the November meeting in New York City, a plan was author- 
ized by which upon the petition of 20 members such meetings might be 
held either simultaneously or following the meeting at which the paper 
was originally read. Two meetings under this plan have already been 


held at Chicago, at which the papers read in New York City on March 21st 
and April i8th were also read by proxy, and discussed. Letters received 
by the Secretary from western members indicate a hearty approval of the 
plan and it seems likely that it will become a permanent practice of the 
Institute, and lead to a most important extension of its influence. Every 
movement of this kind which has been undertaken with a view to extend- 
ing the more general knowledge of the work of the Institute seems to lead 
to a Substantial growth of membership 

Without going into the detailed statistics of your affairs during the past 
10 years, the following statement is of interest, showing the number of 
members who have been elected and actually qualified for membership 
during that period:— 

1884 154 1889 113 

1885 14 1890 116 

1886 n 1891 100 

1887 152 1892 96 

1888 70 1893 165 

The lesson to he learned from this statement is, that there must be yet a 
large number of electrical engineers who may be expected to become mem- 
bers in the near future, and it has been the policy of your Council to main- 
tain the standard of membership in order that such membership become 
year by year of constantly increasing value. The ten volumes of Trans- 
actions already issued form in themselves a very complete record of 
electrical progress during the life of the Institute. Many of the most im- 
portant inventions and researches have first been made public under the 
auspices of this organization, 

The total membership at the close of last year's report was 673, classified 
as follow^s: 

Honorary Members 3 

Members 206 

Associate Members 4^4 

Total 673 

Honorary Members elected during the past year x 

Associate Members elected 179 x8o 

Total 853 

The following have resigned during the year : 








Tctal resignations 14 

The following have died during the year : 



Total deaths 6 

Dropped from the roll on account of non-payment of dues 20 

Elected, but failed to qualify 13 53 




[May 15. 

Leavinsr a toul membenhip of 800 on April yxb, (a aet gain of 127,1 claMi- 
iied as follows : 

Honorary Members 3 

Members 935 

Associate Members 563 


The reports of the Secretary and of the Treasurer show in detail the 
financial affairs of the Institute at the close of the fiscal year : 


For The Fiscal Year Ending April 30, 1894. 

To balance from i8q3 $ 2334 

Receipts for the year 10,385 ^ 

$<o,4oB 60 

By cash to Treasarer 

Secretary's Balance on hand. . . 

.$«o»363 70' 

44 90 

$10,408 60 


For Fiscal Year Ending April 30, 1894. 


Treasurer's Balance from previous year.$ 90 90 
Secretary's " ** '* '' 23 34 

Sundry Receipts s 40 

Entrance Fees 82500 

Life Membership (E. J. Houston) 100 00 

Past Dues sag 15 

' Current Dues 5921 50 

Adx-ance Dues z8i 66 

Electrotypes Sold »53 57 

Transactions Sold 345 31 

Transactions Subscribers 141 45 

Advertising 25473 

Received for Binding Transactions. ... 37 14 

** ** Badges 53*70 

'* Ctrtiiicates 1584a 

'* " World's Fair Fund "4814 

'* *' Congress Book (Advance 

Subscribers) 351 10 

Total. $xo,499 So 



Office Expenses $138 9a 

Office Fixtures is 30- 

Telegrams. 5 72 

Stenography and Typewriting 429 50 

Stationery and Miscellaneous Printing. . 673 56 

Postage ' 296 52 

Messenger Service 39 9^ 

Salary Account...... 1999 95 

Meeting Expenses >23 93 

Rent of Office and Auditorium 900 00 

Express 1x25 

Engraving and Electrotyping 406 03 

Publishing Transactions. 9337 17 

Advertising 7 50 

Binding Transactions snd Periodicals. . . 246 99 

Paid for Badges 64430 

Paid fcr Certificates 337 75 

World's Fair Quarters and Expenses.... 1331 47 

Subscription to Electrical Congress 50 oo- 

Expenses Congress Book 47 5S 

Copyright 5 00 

Duties 1 75 

Secretary's Balance to next year 44 9* 

Treasurer's '* '* " **....... 40754 

ToUl, $10,499 50. 

The outstanding current bills against the Institute, April 30, amounted to . . . 5x«764 46 

Due from m emb ers «»»85 13 

Due from advertisers and others 277 71 

The financial depression of the past year has been severely felt in elec- 
trical circles, and has had its effect in retarding collections. Fortunately,. 


however, this has not interfered with the ordinary administration of your 
a£Eairs, and has certainly not checked the growth in membership, which is 
in excess of any previous year. 

Respectfully submitted by direction of Council, 



New York, May i. 1894. 

From May i, 1893 to May i, 1894. 
Gecirge M. Phelps, Treasurer, in account with 

American Institute of Electrical Engineers. 


Balance from May i, 1893 f 90 90 

Received from Secretary, May 1, 1893 '<> ^'^y 't '^4 xo,363 70 $10,454 60 


Payments from May z, 1893 ^^ ^^Y 't ^^4t ^^ warrantt from 

Secretary, Nos. 499 to 521, inclusive 10,047 06 

Balance to new account 40754 $10,45460 

Balance on hand, General Fund, May i, 1894 407 54 


Balance as per last report $ 850 00 

Interest accrued to May 1, 1894, 3 per cent., to May 14, 1892 and 

2 per cent, thereafter 55 49 90549 

Cash book and warrants herewith for audit. Vouchers are in the hand^ 
of the Secretary, to whom they are returned for filing after payment. 


New York, May 5, 1894. 

Messrs. Hammer and Willyoung were appointed by the Chair 
to audit the accounts 0/ the Treasurer. 

The President : — There are various items of business which 
ought properly to come before the Institute to-day; among 
others are reports from the Committee on Units and Standards, 
and other matters which probably will suggest themselves to 

It may not be amiss now to give one or two notices. The Re- 
ception Committee, to whom is referred the matter of the 

-268 ANNUAL MEETING, |May 15, 

informal reception tendered to our Institute by the Engineers' 
Club, of Philadelphia, and the Electrical Section of the Frank- 
lin Institute, to be held to-night at half-past eight at the Manu- 
facturers' Club, 1409 Walnut Street, wish me to say that they 
have sent no formal invitations to the members, but that they de- 
sire that all shall consider this as an invitation to attend that 
reception to night. I may also state that an invitation has been 
sent to those who care to avail themselves of it, to visit Girard 
College. Those having in charge matters of interest to the 
ladies I think might note that. Girard College is a beautiful 
institution located within ready access to various lines of cars, 
and would well repay the visiting ladies as well as the members, 
if they could find the time to visit it. Also the Athletic Club 
of the Schuylkill Navy. Its clubhouse is open to the gentlemen 
members, and they will be admitted at the door on presentation 
of their badge or card, or on the mere statement that they are 
members of the Amrkican Institute of Electrical Engineers. 
You will find there a very pleasant clubhouse where you can 
have all the advantages of an ordinary club including a very 

f;ood pool of filtered, heated water for swimming. The Frank- 
in Institute of the State of Pennsylvania, the Historical Society 
and the University of Pennsylvania also invite our members to 
visit them. There are also invitations from the new power 
station of the Philadelphia Traction Company, the station of 
the Edison Electric Light Company, the factory of the Chloride 
Accumulator Company, the plant of the Germantown Electric 
Light Company, and other invitations which I do not recall at 
the present time. 

Tne Institute is now open for the transaction of business. Is 
it your wish to take up the reports of the Committee on Units 
and Standards 'i If there is no objection we will take them up 
in the order in which they have been presented. 
The Secretary read the following reports : 

New York City, May 15, 1894. 
To the President and Council American Insth'ute of Electrical Engineers, 
New York City. 

Gentlemen: — Your Committee on '* Units and Standards " desires to submit 
the following report : 

In accordance with instructions from your Committee "On Uncompleted 
Congress Work," a circular letter was addressed to — 

1st. The Institution of Electrical Engineers, London. 

2d. La Societe Internationale des felectriciens, Paris. " 

3d. The Physikalisch-Technische Reichsanstalt, Charlottenburg. Germany. 

4th. The Elektrotechnischer Verein, Borlin. 
requesting the favor of their opinion as to the meaning which should conven- 
tionally attach to the word " inductance." 

This word ** inductance " has unfortunately l)een employed by different 
writers in two senses, and has, therefore, given rise to confusion of meaning and 


{)erplexit7 among students. In Great Britain, Messrs. Oliver Heaviside (who 
originated the term) Andrew Gray^, Dr. J. A. Fleming* and others, have em- 
ployed the term in their writings as representing a coefficient of induction con- 
ventionally symbolized by the dimensional formula L, and the same meaning 
has been employed by a number of writers in this and other countries. On the 
other hand, several of the French writei-s, Professor Silvanus Thompson* in 
Great Britain, followed by Mr. Steinmetz* and others in this country and 
abroad, have employed the word in their writings as signifying the product of 
a coefficient of induction and an angular velocity, conventionally symbolized by 


dimensional formula j; 

It was hoped that the delegates at the Chicago International Congress would 
render a decision as to the meaning which should conventionally attach to th& 
word, but as this hope was not realized and the confusion still continues, the 
above mentioned circular letter was addressed to four of the most prominent 
electro-technical associations of Europe in the hope of ascertaining by the favor 
of their replies, the consensus of opinion upon the subject. We beg to append 
herewith the replies so received. 

It would seem that in the opinion of the Soci^te Internationale, "induct- 
ance " should be regarded as the product of a coefficient of self-induction and 
angular velocity. 

The London Institution of Electrical Engineers considers that the significa- 
tion of the term should be that which its originator, Mr. Oliver Heaviside, 
attached to it, viz., "The coefficient of self-induction." 

The Physikalisch-Technische Reichsanstalt gracefully accepts the meaning 
offered by Dr. Fleming and others, viz., ** A Coefficient of Induction." 
The Elektrotechnischer Verein expresses no opinion. 

In expressing our indebtedness to these institutions for their courtesy in 
according to us their views, your committee desires to recommend the opinions 
expressed by the British and German bodies that " Inductance " should mean 
" A Coefficient of Induction," and while we regret that this opinion is not uni- 
versal, and that the members of so eminent a body as La Societe Internationale 
of Paris should have taken an opposite view of the subject, yet we believe that 
the majority of the opinions obtained entitles us to recommend to the Institutb 
the adoption of the word ** Inductance " as a " Coefficient of Induction " con- 
ventionally symbolized by L. 

Yours respectfully, 

F. B. Ceocker, 
William E. Geyer, 
W. D. Weaver, 
A. E. Kennelly, 
Geo. a. Hamilton, 


1. ** Abs. Meaa. in Electricity and Magnetism ** vol. ii., pp. 344 and 345. 

2. ** The Alternating Current Transformer." 

3. ** Djmamo Electric Machinery," 4th edition, p. 609. 

4. Steinmeu "Transactions A. I. E. E." vol. iz., No. x, p. 61, January, 1893, also vol. x., 
p. 231, April, 1893. 

254 ANNUAL MKBTINQ, [May 15. 

Paris, le 13 Deoembre, 1893. 
Society Internationale des i^lectriciens, Reoonnue d'utilit^ pablique, 

44 Rae de Rennes, 44 (place St. Gerroains-des-Pr^s,) Paris. 
A Monsieur A. K. Kennelly, Chairman 

Ameeican Institute of Electrical Enoineebs, 6 New York. 

Monsieur : — Par votre lettre du 10 Novembre dernier, vous livez bien voulu 
demander ft la Soci6t6 Internationale des Electriciens d^exprimer son opinion 
sur la signification conventionnelle qu'il conviendrait d'adopter pour le terme 

Le desir a 6t6 transmis ft la Sooi6te dans sa dernidre Reunion Mensuelle. 

Gonsiderant qu'une Commission sp^ciale de la Societe a d§lib6re sur ce point 
«n Mai dernier, et que ses conclusions, approuvees en seance, ont 6t6 jpubliees 
dans le BeUetin Mensuel de Juin, 1893 (page 285), la Reunion a 4te (ravis de 
maintenir ses conclusions prec^dentes ft Tegard de la locution visee. 

Ye vous adresse, d'antre part, le fascicule du Bulletin contenant la delibera- 
tion de la SociSte. 

Veuillez agreer, Monsieur, Texpression de mes sentiments les plus distingues. 

Le Secretaire du Comitt, 


Translation. , 

Sir: — In your letter of the 10th ult., vou have expressed a request that the 
Societe Internationale des Electriciens should express an opinion upon the con- 
ventional signification that should attach to the word " Inductance. 

This request has been laid before the Societe at its last monthly meeting. In 
consideration of the fact that a special committee of the Societe consider^ this 
point in May last, and that its conclusions, approved in session, were published 
m the Bulletin Mentiuel of June, 1893, page 285, the meeting decided to main- 
tain its prior conclusion in regard to the said term. 

I beg to forward to you a copy of the Bulletin containing the views of the 
Societe, and remain, etc. 

The following extracts from the record forwarded by the Soci^t^ appear to be 
the only ones bearing upon this question. 

La Commission estime que les expressions de eoeffldent de self-induction et de 
coefficient d'induciion rnutuelle sont employees depuis longtemps sans ambigulte 
et quMl n'y a pas de raison de les changer. 

"La Commission propose de donnerun nom ft la grandeur dont le carre 
ajoute au carre de la resistance d'un circuit traverse par un courant periodique 
donne le carre de sa resistance apparantc. Le nom de reactance pourrait 
convenir ft cette grandeur." 

A full translation of the report has appeared in the Transactions of the 
American Institute, Vol. X., page 419. 

From the official i-ecord, therefore, the views of the Societe might remain in 
doubt. The views expressed by prominent members of the Societe upon " in- 
ductance " appear, however, in discussions upon this subject published in pre- 
ceding numbers of the Bulletin Meneuel^ and which appear in abstract in 
the Transactions of the American Institute of Electrical Engineers, Vol. 
X., pages 407 and 411. From these opinions which are not controverted in the 
official report, the above stated conclusion has been reached concerning the 
attitude of the French Institute in the matter. 

Elektrotechnischer Verein. 

Berlin, den 14ten December, 1893. 
In beantwortung ihres geehrteu schreibens vom 10 v. mts. theile ich ihnen 
ergebenst mit, dass der ausdruck '* Inductance " in deutschen wissenschaft- 
lichen werken nicht gebrauchlich ist. 


loh bedaure daher sehr, Ihnen mit der gewunschen auskunft nicht dienen zu 

H oohachtungs Yoll, 
NoEDMANN, Schriftftthrer des Elektrotechnischer Vereins. 

An das Cdmite on Units and Standards, 

American Ikstitute op Electrical Engineers, 

per A. E. Kennelly, Chairman, New York. 


In reply to your favor of the 10th ult., I beg to inform you that the expres- 
sion ** Inductance" is not customary in German scientific works. 

I therefore regret that I am unable to give you the desired information. 

Nordmann, Secretary of the Elektrotechnisher Verein. 

Phtsikalisch-Technische Reicrsansta^t. Antheilung II. 

Charlottenburg, den 22ten December, 1893. 
Berliner Str. 151. 

Auf the aufrage ihres Committee on Units and Standards vom 14 v. Mts. 
beehrt sich die Keichsanstalt folgendcs zu erwiedern. 

Wie ihnen bekannt sein dCLrfte, wird in Deutschland der Ausdruck *' Induc- 
tance *' aberhaubt nicht ^ebraucht. In rein wissenschaftlichen Abhandlungen 
und der wechselseitigen mduction hauflg die Ausdrucke "Potential einer spule 
auf sich selbst " und "Potential einer spule auf die andere," wahrend in tech- 
nischwissenschaftlichen arbeiten, und neuerdings auch in rein wissenschaft- 
lichen aufsatzen die ersteren Bezeichnudgen bevorzugt werden. 

In der englischen Litteratur wird wenigstens von massgeben den Autoren das 
Word " Inductance " stets im sinne eines Induction Coefficienten angewandt 
und hat somit die dimensionen einer lange (vgl. Z. B. Fleming, The alternate 
current transformer, Vol. I, p. 51 und Hospitalier. Bericht tlber die verhand- 
lungen des Intemationalen Elect rotechnicher congresses zu Frankfuft a M. 1891, 
p. 64) 

In dem ohm'schen gesetz fu r sinusoisale st rome tritt der inductions coefiicient 
L bekanntlich im nenner ^M* + p* L* multiplicirt mit einer Winkelee- 
schwindigkeit p auf, so dass das Product pL die dimensionen eines widersbandes 
hat. Zur Underscheidung von dem ohm'sehen widerstand i? wird deshalb auch 
in der englischen litteratur die gr6sse pL, den man in Deutschland keineu be- 
sonderen namen gegeben hat, «us ** inductive resistance " bezeichnet (Fleming 
loc. cit p. 116); durch diesen ausdruck wird die von ihnen erwahnte zweidettt- 
igkeit im bebranch des wortes, inductance vermieden. 

Physikalisch-Technische Reichsanstalt, 

Antheilung II. Hagen. 
To the American Institute of Electrical Engineers, 

New York City, U. S. A. 
P. T. R., IL, 5524. 


To the question of your committee on ** Units and Standards" of the 14th 
ult., the Keichsanstalt has the honor to reply, a:< follows: 

As you are doubtless aware, the term '' Inductance " is not used at all in 
Germany. In purely scientific works the notion of a coefficient of self-induc- 
tion and of mutal induction commonly finds expression as *' the potential of a 
coil upon itself" or as "the potential of a coil upon another," wnile in tech- 
nical scientific works, and recently also in purely scientific works, the first men- 
tioned expressions are preferred. 

In English literature, at least by prominent authors, the word ** inductance " 
stands in the sense of a coefficient of induction, and has, therefore, the dimen- 

256 ANNUAL MEETING. [May 15, 

sions of a length (see for example Fleming, the Alternate Current Transformer, 
vol. i., p. 51, and Hospitalier Bericht uber die Verhandlungen des Internation- 
alen Electrotechnicer Congresses zu Frankfurt, a M, 1891, p. 64). 

In Ohm's law for sinus oidal currents, the coefficient of induction L is known 
to enter the expression V-K* + p' L* multiplied by an angular velocity p, sa 
that the product p L has the dimensions of a resistance. To distinguish this 
from the ohmio resistance R, the quantity p L which has not received in 
Germany a special name, has, therefore, in English literature been denoted by 
the term **mductive resistance" (Fleming, loc. cit., p. 116); through these 
expressions the ambiguity you have pointed out in the use of the word "in- 
ductance " may be avoided. 

Physikaliseh-Technische Reichsanstalt, 

Section II, Hagen. 

The Institution of Electrical Enoineees. Founded 1871. Incorporated 1883. 
Victoria Mansions, 28 Victoria Street, London, S. W., 
November 28, 1893. 

My dear Sir:— I beg to acknowledge receipt of your letter of the 9th inst., 
which I will take the earliest opportunity of communicating to the Council of 
the Institution. 

I am, my dear Sir, yours faithfully, 

F. H. Webb, Secretary. 

Chairman on the Committee of Units and Standards, 
American Institute Electrical Engineers. 

The Institution OF Electrical Engineers. Founded 1871. Incorporated 1883. 
Victoria Mansions, 28 Victoria Street, London, S. W., 
December 15, 1893. 

DEARSia: — ^Referring to your letter of the 9th ult., the receipt of which I 
acknowledged on the 28th, I beg to inform you that the Council have appointed 
a special Committee to consider the question which you have put to them, and 
as the new Council to whom the Committee*8 report must be submitted do not 
meet until next month, it will be some little time before I am able to send you 
a definite reply. 

I am, dear Sir, yours faithfully, 

F. H. Webb, Secretary. 

Chairman on the Committee of Units and Standards, 

American Institute of Electrical Engineers. 

The Institution of Electrical Engineers 
(late the Society of Telegraph Engineers and Electricians). 
Founded 1871. Incorporated 1883. 
Victoria Mansions, 28 Victoria Street, London, S. W., 

April 18, 1895. 

Dear Sir: — In reply to your request for the opinion of this Institution as to- 
the meaning that should conventionallv attach to the term '* Inductance," I 
am now instructed to inform you that the (^ouncil consider th&t the significa- 
tion of the term should be that which its orginator, Mr. Oliver Heaviside^ 
attached to it, viz., **the Coefficient of Self-induction." 

I remain, dear Sir, yours faithfully, 

F. H. Webb, Secretary. 

Chairman on the Committee of Units and Standards, 

American Institute of Electrical Engineers. 


The PREsrDENT : — You liave heard this report of the Com- 
mittee on Units and Standards. What action will you take on 

Mr. Hewitt : — Would it not be well, before taking action, to 
ask Mr, Steinmetz to give us some reason for using tne term as 
he has in his writings. 

The President : — The Chair would be happy to call on Mr. 

Mr. Steinmetz : — I hardly think I shall be able to give here a 
complete statement answering these questions. 

I did not originate the use of the term " inductance " in this 
meaning as a wattless resistance, but adopted it, following the 
precedence of others, as S. P. Thompson. 

It was in telegraphy that the effect of self-induction was first 
observed in practice, and denoted by the term "time constant of 
the circuit." 

With the advent of alternating current engineering, self-in- 
dnction became of importance in electric light and power distri- 
bution and transmission, as a phenomenon, consuming e. m. f. 
proportional to the current strength, analogous to resistance ; 
witn the distinction, however, that the e. m. f. consumed by the 
resistance is in phase with the current, and thereby represents 
consumption of energy, while the e. m. f. consumed by self-in- 
duction is in quadrature with the current, and thus does not con- 
sume energy, but merely influences the flow of current. 

It became necessary when dealing with alternating currents 
to introduce a term analogous and of the same dimension as 
resistance, and for this wattless resistance as apparently the best 
suitable word, the name inductance offered itself and was applied 
frequently, while the quantity L retained its former name *' co- 
eflScient induction," which seems to me no drawback, since Z ia 
used very little in practice. 

The necessity for a proper name for ^tz N L was universally 
felt ; and a great number of different names were proposed and 
abandoned again ; in short, it was a groping for a proper term^ 
" Magnetic momentum," " inductance speed," " ohmic induc- 
tance," etc. were used. Since, however, the name 'inductance" 
appeared to be the best suitable, and though introduced for Ly 
seemed to me very little needed for this quantity, I saw rib ob- 
jection to the use of "inductance" for ^n N Lot rather for the 
wattless resistance which, as you know, may be due to other 
causes also, as to capacity. 

In circuits containing capacity, we find a wattless resistance of 

the value =f=^^^ which, however, is of opposite direction to 

the inductance of self-induction, hence, is to be introduced as 
negative inductance and has been called "condendance." But out- 
side of self-induction, capacity and polarization which, afi produ- 
cers of quadrature b. m. f.'s, give rise to a true wattless resistance ; 

^m ANNUAL MEETINa. [May 15. 

other phenomena exist which cause a phase displacement be- 
tween current and b. m. f., as mutual induction, live e. m. f.'s of 
synchronous motors, parallel running generators, or induction 

Thus in dealing with the general alternating circuit, the £. m. f. 
can be dissolved mto two components, one in phase with the cur- 
rent and representing consumption of energy, and one in quad- 
rature with the current, or wattless. 

The former is due to the ohmic resistance, hysteresis, etc., as 
more fully discussed in my paper before the Electrical Congress, 
at Chicago, and may be represented by the term *' equivalent 
resistance," while the latter is due to self-induction, capacity, 

While the name "equivalent resistance" for the coefficient 

B. H. F. in phase with the current , i . . • . ^v 
r appears to be quite appropnate, the 

, . , , „ - ,, ^ B. M. F. in quadrature with the current 
name '• mductance " for the term curre nT"" 

is really not very appropriate, since this does not well apply to 
capacity, inductance, etc. 

As a more appropriate name, the term reactance has been pro- 
posed for wattless resistance, and the '* reactance " called " induc- 
tance " when positive, as when due to self-induction, and " con- 
densence " when positive, as when due to capacity or polariza- 

Dii. Frederick Bedell: — I would heartily endorse the re- 
marks of Mr. Steinmetz, but would not ffive to " inductance " 
quite such a general signification; that is, I would limit it simply 
to the term including self-induction, being equal to the coefficient 
of self-induction multiplied by 2 ;r X frequency. To the terra 
including capacity as well as self-induction, the name " reactance" 
has been given and might be retained, although that is not the 
point in question. But when it comes to the question of using 
^Mnductance" as the coefficient of self-induction, or as the pro- 
duct of this coefficient and the angular velocity, it seems to me 
that, for practical convenience and for making mathematical and 
other writing clear, we should choose the latter. 

Mr. a. E. Kennelly : — Mr. President and gentlemen, — This 
matter is a vexed question, because there are two completely 
opposite views in the case. If the question were whether the 
word " inductance " should or should not be applied to a " watt- 
less resistance," that would be one thing ; or whether it should 
or should not be applied to a coefficient of induction, that would 
be another thing. There might be two views to either of those 

?[uestions. But having the word " inductance " in use and in 
requent application, the question is, should it be accepted as 
meaning a " wattless resistance," or as a '* coefficient of induc- 
tion " ? Here is the great confusion, and if we look through 
the writings of this countrjr and the writings of Europe, we 
frequently find these two different meanings employed tor the 


game word indactauce ; so it is very important that some con veD- 
tion should be made to decide whicn meaning to retain, and when 
we have once selected that meaning we should adopt it there- 
after, no matter what our own particular views may be. I think all 
of us are ready to sacrifice our own personal views for the bene- 
fit of electrical engineering, if we can only have a settlement of 
the matter once for all. We all hoped that the Chicago Electri- 
cal Congress would settle it ; that they would place their dictum 
on this matter and say we want "inductance" to mean so and 
so. But the Chicago Congress unfortunately had many other 
things to attend to and they left the matter absolutely untouched. 
So in the- hope that we might settle this question before the 
next Congress convenes and tnus avoid further confusion, these 
letters were addressed, under the direction of the committee on 
Congress work, to the Institutions of Europe asking for their 
opinions. We have received four opinions from Europe, and two 
of those opinions are in favor of using "inductance" as the co- 
efficient of induction. The members of the French Institute, on 
the other hand, have shadowed their belief that it should be used 
to mean a "wattless resistance." Our own committee was in 
favor of using it as the coefficient of induction. So we submit 
that the general opinion is in favor of using " inductance " as 
the coefficient of induction, and not as a resistance. One strong 
argument is that the man who introduced this term, Mr. Oliver 
Heaviside, introduced it as the coefficient of induction, and the 
burden of proof should be on those who want to change the 
meaning that he gave, to show why it should be changed. We 
submit, therefore, that the Institute should adopt the term as 
meaning, either a coefficient of self-induction or of mutual in- 

The PREsroENT: — What action will you take in this matter? 

Mr. James Hamblet:— I move that the decision of the Insti- 
tute be as the committee has recommended. 

Mb. Steinmbtz : — I fear that the adoption of such a definition 
of the term "inductance" will tend to increase the confusion 
by inducing writers to use the terra without definition, while 
now, where the term " inductance" is known to be ambiguous, it 
is usually defined when used, for instance, by tlie addition of 
"ohmic," etc. 

How difficult it is to get universal adoption of such a name, 
especially by those who before used a different name, has been 
shown by the fate of the term "effective." Several interna- 
tional congresses adopted the name " effective value of the alter- 
nating wave " for the square root of the mean square, since this 
represents the effect on the power of the wave. Before the 
adoption of this term, S. P. Thompson had introduced for this 
quantity the term " virtual," and has never accepted the terra 
" effective," and the result is, great confusion, especially among 
those very people for whom S. P. Thompson's book is written — 

260 ANNUAL MEETING, [May 15, 

the students of electrical en^neering. European bodies are in 
general not in sufficiently close touch with the practice to be 
able to say whether the one or the other definition is more con- 
venient, so that their opinions in this case are not as important as 
in strictly scientific matters ; consequently I would rather like to 
see the question unsettled until a future time when practice will 
have decided which is the more convenient. 

I am inclined, however, to prefer the term '-^ reactance " and 
to restrict the term inductance to the reactance of self and 
mutual induction. 

Mr. Kennelly : — Does Mr. Steinmetz mean that we should 
try to sustain the confusion that exists? Surely if confusion 
does exist, as he admits, should you not try to come to some con- 
vention that shall put an end to that confusion ? 

Mr. Steinmetz : — Have we the best ? 

Mr. Kennelly : — We have adopted the best means that we 
knew of. 

The President:— Mr. Hamblet's motion is before the house. 
Does any other gentleman wish to speak? It is moved and 
seconded that the Institute adopt the recommendation of the 
Committee on Units and Standards as to the meaning that should 
be attached to the word " inductance." 

[The motion was carried.] 

Mr. Steinmetz : — The general consensus of opinion is that a 
term is badly needed for the " wattless resistance," that is, the 
" quadrature component of impedance," for which I intended to 
use the term "inductance." Inductance has been taken now 
for the coefficient of self-induction. Therefore I propose that 
the Institute adopt as the term for the ratio : 
quadrature component of e. m. f. . .. ^ , „ 

2 r — the name " Reactance. 


Mr. Kennelly : — I second the motion. 

The President : — It is moved and seconded, as you have 
heard. If the Chair may express an opinion, itwould be that 
this is a very good settlement of the question. 

[The motion was carried.] 

The President: — There is another recommendation of the 
Committee on Units and Standards. 

The Secretary read the second recommendation of the Com- 
mittee favoring the legalization by the United States Congress 
of the electrical units adopted by the Chicago Electrical Con- 

Sess of 1 893, and also the following extract &om the report of 
e New York meeting. 

Prof. Crocker : — I move that it is the sense of this meeting that the passage 
of the bill legalizing the electrical units adopted at the Chicago Electrical Con- 
gress of 1893, be recommended. 

Mr. George M. Phelps: — Mr. Chairman, if you will permit me I will sug- 
gest a slight addition, to make the action possibly stronger, and that is, that 


this meeting recommend to the general and annual meeting of the Institute 
to be held in May, a more formal endorsement and recommendation of the 
measure. I offer this because one or two speakers suggested that this meeting 
give its sense on this subject, and that the general meeting in May might take 
a more formal action. 

Prof. Crocker: — I accept the amendment. 

The President: — Gentlemen, it is moved and seconded, as you have heard. 
Are you ready for the question? 

[The motion was put and carried.] 

The PBESiDENr :— What action will you take on this recom- 
mendation ? 

]kf R Hewitt : — Would it not be in order to specify in the res- 
olution the manner of presenting it to Congress ? 

The President :- -I think it would be well for the Institute 
first to determine if it wishes to adopt this resolution. The 
question is on the adoption of the resolution. Afterwards you 
can determine how it is best to carry it out. 

Mb. Carl Herino : — I move that the resolution be adopted. 

[The motion was carried.] 

The President: — ^I think it would be proper for the iNSTrruTE 
to appoint a small committee to see that this matter be carried 

Mb. Hering: — I suggest that the Committee on Units and 
Standards constitute this body. 

The President ; — It is moved hj Mr. Hering that this matter 
be referred to the Committee on Units and Standards. 

[The motion was carried.] 

The President : — There is another announcement I wish to 
make. Mr. Edwin J. Hall, of tlie American Telephone, and 
Telegraph Company, says that the company desires to extend the 
use of the long distance lines to the members of the Institute 
while they are in this city The office of the company is at 114 
South Fourth Street, Philadelphia. The secretary has some an- 
Douucements to make 

The Seobetaby : — At the meeting of the Council held this 
morning the following associate members were elected : 

Name, Address. Endorsed by. 

Berresford, Arthur W., B. 8,^ M. E. Electrician. Brook- Samuel Sheldon. 
Ivn City R. R. Co., 197 Van Frederick Bedell. 
Suren St., Brooklyn, N. Y. Aug. Tread well, Jr. 

BiJUR, Joseph Student in Electrical Engineering, *F. B. Crocker. 

Columbia College, Residence. George F. Sever. 

41 West 53rd St., New York M, I. Pupin. 

Chadbourne, Henry R., Jr. Electrical Engineer, Trov T. C. Martin. 
City Ry. Co., Troy, N. Y, * E, G. Bernard. 

J. B. Cahoon. 
Cha8. D. Shain. 

Childs, Sumner W. Supt. of Line Construction, J. G. C. G. Young. 

White & Co., 1425 Maryland J. G. White. 

Ave., Baltimons Md. Wm. C. Burton. 


[May 15, 

Clark, LeKoy, Jr. 
doolittle, c'larewt^k k. 
Dorr, Frank H. 
Gladino, Frank W. 
Hartwrll, Arthur, 
Haviland, Foster L. 
Hewitt, William R. 

HoLBERTOX, George C. 
Morse, George H. 

Nicholson, Walter W. 
Philbrick, B. W. 

Post-Graduate Student in Electrical 
Engineering, Columbia College, 
350 W^st 30th St., New York 

Manager and Electrician, Roaring 
Fork Electric Light and Power 
Co., Aspen, Colo. 

M. I. Pupiii. 
H. A. Storrs. 
F. B. Crocker. 
F. B. Bwlt. 
A. H. Cowles. 
Wm. A. Anthony. 

Engineering Dept. General Elec- 
tric Co, 425 Baker St., San 
Francisco. Cal. 

Ijehigh University, 2005 East 
• York St., Philadelphia, Pa. 

T. C. Martin. 

Jos. Wetzler. 

L. Stieringer. 

Edwin J. Houston. 

A. E. Kennelly. 

George E. Wendle. 

Electrical Engineer. Westinghouse Chas. A. Terry. 

Electric and Mfg. Co., Pitt«- Albert Sch mid. 

burg. Pa. Charles F. Scott. 

With Clark Electric Co., 192 E. P. Clark, 

Broadway ; Residence, 163 St. Ralph W. Pope. 

Nicholas Ave.. New York City. R. N. Bayiis. 

Special Student, Electrical Dept. M. I. Pupin. 

Columbia College ; 130 E. 60th IL A. Storrs. 

St., New York City. Resi- C. T. Rittenhouse. 

dence, San Francisco, Cal. 

Electrical Engineer, General Elec- A. L. Rohrer. 

trie Co., 15 First St., San Fran- H. F. Parshall. 

Cisco, Cal. Wm. E. Geyer. 

Assistant Instructor in Electrical G. D. Shepardson. 

Engineering, University of Min- Moigan Brofjks. 

nesota, Minneapolis. Residence, M. H. Gerry, Jr. 

Excelsior, Minn. 

General Supt. Central N. Y. Tele- F. A. Pickeniell. 

Shone and Telegraph Co., 73 U. N. Bethell. 
[oward Ave., Utica, N. Y. Hammond V. Hayes. 
Electrician, in charge of Electrical T. C. Martin. 
Plant. Levi P. Morton, Rhine- Chas. D Shain. 
cliff, N. Y. F. Saxelby. 

E. G. Bernard. 

RicKER, Charles W. Expert Electrical Engineer, 109 Chas. R. Cross. 

White Building, Buffalo, N. Y. Edw. E. Higgins. 

Henry H. Wait. 

Sharp, Clayton H. Instructor, Department of Physics, Edw. L. Nichols. 

Cornell University, 122 Univers- Harris J. Ryan. 

ity Ave., Ithaca, N. Y. C. P. Matthews. 

Stine. Prop. Wilbur M. Director Electrical Dept., Armour Edw. Caldwell. 

Institute, Chicago, 111. Joseph Wetzler. 

H. A. Foster. 

Tower, George A. 

Wharton, Hugh M. 

Winchester, Samuel B. 

Total 21. 

Electrical Engineer, The Sherwood M. B. Leonard. 

Land Co. and The Jefferson Ho- C. E. McCluer. 

tel Co., 109 S. First St., Rich- George Hill. 

mond, Va. 
Electrical Engineer, Westinghouse A. E. Kennelly. 

Electric and Mfg. Co., 29 Edwin J. Houston. 

Plane St., Newark, N. J. L. A. Osborne. 

Supt. and Electrician, Holyoke C. P. Steinmetz. 

Water Power Co , 9 Laurel St., W. L. R. Emmet. 

Ilolyoke, Mass, Theodore Stebbins. 

The following associate members were transferred to full 
membership : 


LoRRAiN, James Grieve Norfolk House, Norfolk St., London, W. C, Eng- 

Wiener, Alfred E. Electrical and Mechanical Engineer, General Elec- 

tric Co. , 24 Yates St . Schenectady, N. Y, 

Craigin, Henry A. Engineer. Westinghouse Electric and Mfg. Co., 15 

Charles St., Boston Mass. 

Hasson W. F. C. Consulting Engineer. 104 Sutter St., San Francisco, 


Ives Edward B. Lieutenant U. S. A., Electrical Engineer, nth and 

ColonaSts., Philadelphia, Pa. 

Total 5* 

The Secretary also read invitations from the following: A. 
Falkland, Girard College, The Historical Society of Philadel- 

fhia, The La Roche Electric Works, Queen & Co., Dr. William 
^epper, The Germantown Electric Light Company, The Engin- 
eers' Club, Dr. Wahl, Secretary Franklin Institute, Edwin J. 
Houston, on behalf of the Athletic Club of the Schuylkill Navy, 
and the Drexel Institute. 

The President: — Gentlemen, there is a matter which was 
laid on the table at one of our meetings which you may wish to 
bring up. It is my duty, as presiding officer, to call your atten- 
tion to the fact— the report of the Committee on Revision of the 
Rules, do you wish to take it up now, or is there any other busi- 
ness that you would like to take up ? 

Mb. Hewitt : —Mr. President, we have a communication from 
a member in Chicago in reference to certain matters which con- 
cern the Institute. It seems to me this would be a good time 
to consider it. Although it is stated that there is a memorial 
which is to be presented later it may come at some time when 
we are busy with something else and we should not be able to 
give it attention. I move that this matter be brought up now. 

[The motion was seconded and carried.] 

The Secretary read a letter from Mr. Caldwell, local honorary 
secretary, stating that a memorial had been prepared by a com- 
mittee appointed for that purpose, asking that the expenses of 
the meeting at Chicago, for reporting, postage etc., be paid from 
the generaif unds of the Institute. 

NlR. GEX)RaR M Phelps : — In order to have some action to 
discuss I would move a resolution as follows : 

Resolved: That the expenses of reporting the Chicago meet- 
ings up to a sum not exceeding $10 per meeting, be borne by 
the general fund of the Institute until further notice. 

I offer that resolution because, like many other members, I 
have been exceedingly impressed by the success of the recent 
meetings at Chicago and the merit of the discussions that have 
taken place there. It is practically out of the question for mem- 
bers in that vicinity to attend a meeting in New York oftener 
than once a year or so, and they have, I think, amply justified 
their proposition to have local meetings and have done useful 
work. It seems very proper that we should bear so very reason- 

264 . ANNUAL MEETING. [>Uy 15, 

able a portion of the expense as suggested in the conimnnieation 
from Mn Caldwell. 

Me. Hewitt : — I second that motion, Mr. President 

The President: — Mr. Phelps' motion has been seconded. 
Does any other gentleman wish to speak on the subject ? 

Mr. Phelps : — I think, Mr. Chairman, that it is a matter that 
had better be well discussed and I would like to hear expressions 
from other members. 

The President:— This is a matter, gentlemen, that you can- 
not be too careful about deciding properly. It is not the matter 
of an expense of $10 for a single meeting, but it is the very grave 
matter of precedent. The Institute should, I think, properly 
consider the future as well as the present, and while 1 would be 
equally desirous with any member of doing all in my power 
to obtain the freest discussion, yet I think we ought to consider 
carefully as to whether or not in the establishment of such a pre- 
cedent we are not in dangier of increasing the annual dues of 
membership. I think that should have a luU discussion. 

Mr. Hamblet : — Do 1 understand Mr. Phelps' motion to limit 
the expenditure to the reporting of the discussions at the Chi- 
cago meetings? 

Mr. Phelps : — The only request that we have before us is to 
do exactly that thing. The letter is quite specific and a resolu- 
tion or some remarks at the end of the printed report of the Chi- 
cago meeting is to the 6ame effect ; that it was the sense of the 
meeting that the general fund of the Institute should meet the 
expense of reporting their meetings. There was in addition 
some little charge for stationery mentioned by Mr. Caldwell, but 
he states that it is their opinion that the estimate of $10 per 
meeting would more than cover the expense contemplated. The 
expenses contemplated, I believe, are merely a stenographic re- 
port and such stationery as is required by the local honorary sec- 
retary in conducting the correspondence. 

Mr. Hewitt: — I think that with respect to a great many 
papers, the discussion is of as much value, if not more value, 
than the paper itself, and anything that this Institute does to 
bring forth increased discussion, redounds to the interest of the 
Instfiute and to the benefit of the members, and anything that 
we may do in order to aid this wider discussion is to our benefit. 
I do not sympathize with the President exactly in the fear of 
increased dues, because I believe that the encouragement of 
these meetings in Chicago and other such cities will so increase 
our membership as to offset the light extra expense. I well know 
the President's fears from his expression of tnem elsewhere, but 
I must say that I cannot feel in sympathy with him on this ques- 

Mr. Hammer:— I would like to ask for the reading of the re- 
solution in the letter again. 


The Secretary read the part of the letter referred to. 

Mr. Hamaieb: — 1 think it is very reasonable that tlie Chicago 
people should expect to have a certain amount of the funds of 
the Institute placed at their disposal. 1 think it ought to be 
done only, however, after careful consideration of just how it 
should be done. 1 think at the time this question of local meet- 
ings was threshed out in the different Council meetings this very 
f)oint came up among others, and it was suggested then that if 
ocal bodies were organized, and after their membership attained 
a certain number, the Institute would assume a certain por- 
tion of their expenses. It seems to me that if this matter was 
referred to a committee they could consider it very carefully and 
recommend some plan that would be fair .to Chicago and to 
other cities that would take the matter up hereafter. Supposing, 
for instance, it was decided that when Chicago gets fifty mem- 
bers, each of which members paying annual dues of $10, the 
amount would represent $500. !Now the Institute would re- 
ceive that $500, and in view of the fact that there are fifty mem- 
bers of the Institute residing in Chicago a certain percentage of 
the receipts could go to that organization, and for any expenses 
which they would incur over and above that amount the local 
organization would have to be responsible. I merely give this 
AS a suggestion. It seems to me, as the President says, we ought 
to be careful in deciding this matter, because it is more readily 
corrected now than hereafter. If the matter is referred to a 
committee, I think they could formulate some plan which would 
give satisfaction to Chicago and other cities which would form 
local organizations hereafter. I, therefore, make a motion that 
this matter be referred to a committee, say, of three appointed 
by the Chair. 

Mb. Phelps : — Mr. President, I tried to express the resolution 
with spme particularity, so that it should not be too broad, nor 
establish a too serious precedent. The resolution, if it was taken 
down as I meant to express myself, was confined strictly to the 
request in the letter of Mr. Caldwell, namely, to liave the ex- 
pense of reporting the meetings and the stationery paid. Now 
that resolution, if passed, I think, vould not necessarily commit 
the Institute to incur tlie general expenses of local bodies or 
sections at any time. It meets this specific request, on the 
ground, in my mind, that the work done has already been useful 
and is likely to become more important ; that it has led already 
to the acquisition of five members, there is $50 ; and the ex- 
penditure under the resolution I have offered is limited to $10 a 
Tueeting. There are not likely to be more than a half dozen 
meetings in a year, and I think it would be well to determine the 
point here and now, rather than put it in the hands of a com- 
mittee to report at some subsequent period. If the committee 
propose to report at this meeting, I do not think they can do 
much better than the meeting itself on that very distinct pro- 

966 ANNUAL MMETING. [May 15, 

poBitiou, which I do not regard as a general permiesion to all 
and sundry meetings to charge the Instftdte with all and sundry 

The Seobetart : — 1 would like to make a few remarks for 
the information of the meeting regarding the expense. The 
Armour Institute at Chicago has very kindry^ placed at our dis- 
posal a hall with all neces^ry facilities, without charge. The 
notices for the meetinffs at Chicago have been includeu, as you 
are aware, in the regular postal notice which is sent out to all 
members wliich adds nothing whatever to the outlay. The 
cost woi^ld be the same either with or without the Chicago 
meetings. This reduces the amount simply to the communica- 
tions of the local honorary secretary with the New York office, 
or such communications as he may make with the members there 
in arranging for meetings ; so that there is really very little ad- 
ditional expense beyond the reporting of the discussion. We 
have bad the discussion of two of their meetings, and that of 
the last meeting was printed in the May number, copies of which 
are here for distribution ; that, of course, involvea, in addition 
to the fee for reporting, the necessary proportion of the cost 
of printing the Transactions. But, as Mr. Hewitt has very pro- 
perly 8aid, everything of the kind that is done adds to the value,, 
of the Institute to the membership generally, and I have it 
from the gentleman who read the last paper that he considered 
the discussion at Chicago, so far as the question of practical ex- 

?)rience was concerned, as of more importance than the New 
ork discussion ; that is to say, the western men had done cer- 
tain work in the line of the paper, and gave their experience. 
Now, if that discussion is of any value to anybody here, it has 
been brought out by this Chicago meeting. 1 presume that if 
that meeting had not been held, these facts would not have been 
brought out in the Transactions. It has been the policy, of the 
management to make the Transactions as valuable to the mem- 
bers as possible, so that each one would feel that he was getting 
a full return for the money spent, and, personally, I have never 
considered the Institute a concern for accumulating a fund, and 
I do not believe that technical societies should be so considered, 
but rather that they should expend their money, as the rulea 
say, in " the reading and discussion of professional papers, and 
" the circulation, by means of publications among its membera 
" and associates of the information thus obtained." 

That is the principal reason for the existence of such an insti- 
tution a« this. 

There is just one other point I wish to bring up in connection 
with the work of the secretary and the work of these local meet- 
ings. Airy one who has anything to do with running a local 
organization, such as has been suggested, knows that the collec- 
tion of dues is one of the most annoying things in connection 
with it. By the plan we are pursuing, or which is being dis- 


cussed, the local secretary is entirely relieved of that burden. 
The members simply carry on the meeting, and this is done for the 
benefit of the national body as well as themselves, and they pay 
their dues in one lump. This removes the probability of any ir- 
ritation on the part of members in the vicinity who might 
say, "Why here we are paying $13 a year for our membership, 
" and in the vicinity of New York they pay but $10 per year, and 
" they get just as much benefit as we do." That is the way I 
have to look at this matter from the standpoint of members at 
various points, because I am in communication with them. This 
matter has been brought up by the Chicago members, who 
practically ask us "Why should not the Institute pay for steno- 
" graphic reports of our discussion of the papers, as well as the 
" discussion of these papers elsewhere ? " 

Mr. Phelps : — I wish to say a word more to back up my re- 
solution. A committee was appointed last autumn to consider 
this matter of local meetings and spent quite a good deal of time 
and care in presenting a plan. That plan was thought at the 
time by some people proposing local meeting, perhaps bv some 
in Chicago, to have been somewhat restrictive of tne neld of 
such local meetings, because it required that such local meetings 
should discnss onlv such papers as were accepted by the Insti- 
tute to be read at its meetings here. The plan has been accepted 
at Chicago in perfect good faith. The same papers have been 
read there, and, if possible, simultaneously, and have been dis- 
cussed in both places. In other words, the western members 
have been doing part of the monthly work of reading and dis- 
cussing papers. They have done it in Chicago while we were 
doing it in New York. It seems to me they were doing pre- 
cisely the same work that we are doing, and simply by their dis- 
tance they are debarred from doing it with us here. If they 
were running an entirely distinct sort of meeting, having their 
own papers which were not necessarily a part oi the Transac- 
tions OT the Institute, the case would be quite different. 

Mr. Hamblet : — The matter of the accession of five members 
seems to me some sort of compensation to the Institute for the 
expense. It is said five members would bring in $50, but for 
the first vear it is $75. The cost of each meeting in Chicago, 
merely limiting it to the stenographic report, would amount for 
the eight meetings to about $80. By allowing that expense to 
the Chicago meeting, are we not binding them more closely to 
us, and also getting the advantage of the educational value of 
their discussions in the Transactions, as well as the increase of 
membership ? It has been said that this is an entering wedge, 
and rather a dangerous plan for us to adopt, to expend money on 
these meetings. I acknowledge that there may be some doubt 
about the policy of doing so. But it seems to me at present, in 
the aspect of the work hat has so far been done in Chicago, we 
are warranted in allowing them some small expense. 

268 ANNUAL MEETING. [May 15, 

Mb. Stbinmetz : — While it seems to me quite fair that some- 
thing should be done to help the Chicago local meetings, at the 
same time we should proceed very considerately in this matter. 

It is a happy fact, tnat the Chicago meetings begun under very 
favorable circumstances^ and their expenses are very low. But 
with the same right that Chicago members request us to share 
the expenses, other local meetings can, and wiU do the same, and 
should be treated in the same way, and other local branches may 
have a good deal larger expenses. Therefore, we ouglit, at least, 
to specify what we intend to pay, and thus I make the amend- 
ment to the motion that the Institutb pay the cost of reporting, 
but nothing else; but not only of the Chicago meeting, but any 
other section which may be established. I think that would re- 
strict the possibility of having too large expenditures at such 
meetings, and at the same time I think it fair to pay the expenses 
for that in which we are mostly interested — improving the 
Transactions by improving the discussions. 

Mr. Kennelly : — I second the amendment. 

Mr. Hering : — That puts no limit on the amount which can 
be expended, and I, for my part, think it would be much better 
to limit the amount to $10, as Mr. Phelps suggested. When the 
meetings become more and more important, and the reporting 
more expensive, there is nothing to prevent us from granting a 

freater amount. To promise to pay for the expense of reporting 
think would be imprudent, because that is too indefinite a 
quantity ; it would be much better to fix upon a certain sum. 

Prof. Anthony : — It seems to me we had better confine our- 
selves here to this specific case that is brought before us, and 
when some other meeting wants its expenses paid, we can take 
that up as a separate case. I do not see the need of crossing that 
bridge until we come to it. I do feel that in the case of the 
Chicago meetinp: the discussions have been very valuable. They 
will form a valuable feature of our Transactions. The Chicago 
meetings have been of advantage to the Institute at large. They 
are not simply little meetings, of advantage only to those attena- 
ing them, and, therefore, it seems to me perfectly proper that we 
should bear that expense. The discussions are of just as much 
value to the Institute at large as those in New York. For this 
reason I am heartily in favor of paying for the reporting, and 
whatever expense there may be in connection witli obtaining 
these discussions for our Transactions. But I am not in favor 
of passing any resolution that will bind us to do anything in 
particular in tlie future in reference to any other meeting or in 
reference to this one. We pay up to $10 now. By-and-by if we 
find that the reporting is going to cost more, we can change that 
resolution and pay more if we think it desirable. 

The President: — The Chair will now put the vote on the 
amendment of Mr. Steinmetz to Mr. Phelps' motion. 

If you will pardon me, the Chair would like to make a few 


remarks. The President does not wish to be misunderstood in 
his position, as he fears, from some remarks made in the discus- 
sion, that he may be. The President is in hearty sympathy with 
any movement which will increase the value of the Institute 
and the value of its Transactions by offering free discussion to 
its members wherever they may meet. The Chair has expressed 
an opinion that it is the part of wisdom of this Institute to be 
careiul lest in any legislation here it establishes what might prove 
to be a dangerous precedent. The Chair particularly wishes its 
position to oe understood. It inclines to the opinion that the 
broad question raised in the Chicago meeting is not met by Mr. 
Phelps motion. As the Chair understands it, the particular 
question raised in the Chicago meeting is this : That the expenses 
incurred in connection with the local meetings shall be paid out 
of the general fund, and the Chair has expressed its opinion 
that that is a dangerous precedent unless it is carefully considered. 
I rejoice with any member in the growth of our Institute. I 
am not quite able to see that the five members who have joined 
the Institute since the date of the Chicago meeting would not 
have joined had that meeting not taken jJace. That has by no 
means been proved. Your President certainly does not look on 
the Institute as a money getting organization. Certainly it is 
not desired that the funds of the Institute shall be simply accu- 
mulated for the sake of being accumulated. The President does 
not think the society is in any immediate danger of being ruined 
by too large sums for that or other purposes. But while I have 
the honor of occupying your Chair, I shall never hesitate, even 
though I may be in a hopeless minority of one, in expressing to 
you decidedly what my views are on any subject that may in- 
volve the good name and success of the Institute. Therefore, 
before putting this question, I would like to suggest to you that 
this is not meeting the issue raised in the Chicago meeting. 

Mb. Phelps :— Mr. Chairman, if you will pardon me, I wish 
to point out that the purpose of my resolution was not to meet 
that broad question, but to meet a much more specific and narrow 
one ; to satisfy that particular demand or request, but not to go 
to the length of accepting the proposition of the Chicago meet- 
ing that we were responsible for all their expenses. Mr. Stein- 
metz's motion would create a much broader action and be more 
in the direction of meeting that large issue. I was very glad 
that Professor Anthony expressed himself as he did in respect to 
those points. 

Tbe President : — The Chair has nothing to add, except that 
it simply desires to express the opinion that as this question has 
come up it is preferable that the Institute shall meet it. I will 
call for a vote on Mr. Steinmetz's motion. 

[Mr. Steinmetz's amendment was lost.] 

The Pbesident : — The vote will now be taken on Mr. Phelps* 

^0 ANNUAL MEETING. [May 15, 

[Mr. Phelps^ reeolution was carried.] 

The Presidkkt: — What other bnriness will you present? 

Mb. Hammer : — I would like to report on behalf of the com- 
mittee for examining the books of the Treasurer, that they have 
been audited and found correct.^ 

The President: — Mr. Secretary, will you please inquire of the 
tellers what probability there is that a report will be had from 
them shortly. 

The Secretary made the desired inquiry of the tellers and re- 
ported, as follows : 

Mr. President, the tellers inform me that they will probably 
not be able to make a report for an hour or more, and they wish 
me to bring before the meeting for instructions this question: 
According to the rule which they refer me to, that is Kule V^ 
paragraph 4, " on this outer envelope the member shall add his 
signature and a postage stamp." They hand me these envelopes, 
upon which the name is either typewritten or imprinted with a 
rubber stamp ; in one case embossed. It answers the purpose of 
showing who the envelope is from, but it is not a signature. 

The President : — This is a matter for you to decide, gentle- 

Mr. Hammer : — I move that they be accepted upon the en- 
dorsement of the committee. 
S'he motion was carried.] 
R. Phelps: — Would it be in order to call up now the report 
of the Committee on Revising the Election Rules? If any- 
thing is to be done, I think this would be a suitable opportunity. 
I move that it be taken up. 

[The motion was carried.] 

The President : — 1 will ask the Secretary to read this report. 

The Secretary read the following report : 


At a meeting of the Committee, duly held, it was Unanimously resolved to 
lulvise that the rules relating to elections be immediately changed as set forth 

In pursuance of this resolution and of the provision in Section VIII., con- 
trolling the manner in which amendments may be made, the prescribed written 
notice is hereby given by the Chairman on behalf of the Committee. 

At the next or at some subsequent regular meeting of the Institute the fol- 
lowing separate amendments of the rules will be brought up: 

Resolved, that Section V. be amended as follows : 

1st change — After "a" in line 18, add the words *' second list headed." 

2d change — Line 18, after "choice" add "opposite the name of each 
nominee in each list shall be printed a number indicating the number of 
nominations received by him, and a suitable ex[)lanation of these numerals shall 
be placed on the sheet." 

3d change — Lines 38 to 36, shall be changed to read * * sealed unmarked and 
unidentified * Inner envelope' of any suitable character, to be in its turn 
enclosed either in the 'Voting envelope' (received from the Secretary) or in any 


other envelope marked on its face * Non-official Voting Envelope-Enclosing a 
ballot only.' The outer envelope of either class must be identified by the 
signature of the memlwr on its face, and must be sealed and mailed to the^ 

Respectfully submitted, 

t F. Benedict Herzoo, Chairman. 
Jan. 17, 1894. Signed, \ T. C. Martin. 

( F. R. Upton, Assenting. 
[For existing Rule, see Member's pocket year-book, edition 1893, p. 52, 
also Transactions Vol. ix. p. 460.] 

Mr. Phelps : — I wish to oflFer a slight addition, or an amend- 
ment, so to speak, not changing anjtliing in this rule as it would 
read amended by the committee, but as an amendment to the re- 
port of the committee, if you please ; an addition at the end of 
the second paragraph, the "last sentence of which is : " This sheet, 
" together with an envelope, on which shall be printed the ad- 
*' dress of the Secretary, and tlie words * Voting envelope — en- 
*' closing a ballot only,' shall, not later than the 15th of April, 
" be mailed by the Secretary to every member in good standing." 

I would add there "Provided that members elected after April 
" 15th, and who shall have paid their dues shall be supplied with 
*• ballots on request at any time before the election." 1 oflFer that 
for this reason. It appears that a considerable number of mem- 
bers now in good standing, elected at the Council meeting imme- 
diately following April 15th, who have paid their dues, find, 
under a recent interpretation of the rule, that they are debarred 
from voting, although they are members in good standing and 
have been so for some weeks. This would meet a case of that 
kind. I hardly think that this was intended to exclude members 
from voting, but was intended for convenience — that the Secre- 
tary should on that date mail these tentative ballots to all the 
members then in good standing, but this would exclude any 
doubt on that subject. 

[The motion was seconded.] 

The Secretary : — I would suggest to the gentleman propos- 
ing the amendment, that the Secretary should send these ballots 
to aU members who pay their dues who are elected subsequent to 
April 15th, instead of sending them upon request. That is to 
say, I think the members who were elected should be entitled 
to these ballots whether they request them or not. Not being 
familiar with the modus (ypera/ad%^ they may not ask for them. 

The President : — Does Mr. Phelps accept that change ? 

Mr. Phelps : — Yes, sir. If you will permit me, I will word 
that a little differently to meet the Secretary's suggestion. 

The Secretary : — There is nothing in the language of this 
rule fixing a limit to the time of receiving ballots. 1 had ballots 
handed to me this morning by the tellers who asked whether they 
should be counted. So far as I know, there is no limit, provided 
they are handed in before the tellers finish their wonc. If a 

272 ANNUAL MEETING. [Maj 15, 

person should hand his vote to the tellers now, while the count is- 
proceeding ; as the rule is construed, there would be no reason 
why they should not count it. 

The President: — Pending the preparation of Mr. Phelps'^ 
resolution, in pursuance of the suggestion of the Secretary, tne 
Chair wishes to be advised by the Institute what action shall be 
taken on those ballots. , Unless the Institute determines to th& 
contrary, the Chair will request the tellers to accept them as bona 
fide votes. Will you take some action on that matter ? 

It was voted that the ballots be accepted, and the tellers were 
instructed accordingly. 

The following amendment to be added to the second paragraph 
of the report or the Committee on Revision of the Eules, mtro- 
troduced by Mr. Phelps, was adopted : 

'* Provided that the Secretary shall also mail such ballots, 
" sheets and envelopes to members qualified after April 15th 
" before the annual meeting, and that any member not having 
" ballots and envelopes shall be entitled to obtain them from the 
" Secretary at any time before the calling to order of the annual 
" meeting." 

On motion of Mr. Carl Hering, it was also voted to amend 
the committee's report by making the following change at the- 
end of the fourth paragraph. Ihe proposed rule wnich now 
reads " and must be sealed and mailed to the Secretary," shall 
be changed to read "be sealed, and must reach the Secretary 
prior to the hour of the actual opening of the annual meeting." 

The annual meeting then adjourned, pending the preparation 
of the tellers' report. 

The annual meeting reassembled, and was called to order by 
President Houston at 2.30 p.m. 

The President: — Mr, Secretary, is the tellers' report ready? 

Mb. Upton : — We have not made a full report. The canvass 
of the votes showed that the entire Council ticket was re-elected^ 
We will make a full report to the Secretary, giving the items 
showing the number of votes cast for the various persons. The 
majority is quite large and full for the entire Council ticket. 

Philadelphia, May 15, 1894. 
We find the result of the balloting as follows : 

For President, Edwin J. Houston 236 

'* " T. D. LocKwooD 48 

The balance of the Council nominees were also elected, each having a majority 
of the 365 votes cast. 

Geo. R. Metcalfe, i 
Francis R. Upton, f Tellers. 

The vote in detail is as follows : 





E. J. Houston . . . 
T. D. Lockwood 

E. L. Nichols 

Nikola Tesla . . . 

F. B. Crocker. 





A. B. Kennelly 11 

Elihu Thomson 8 

Elisha Gray « 

Chas. R Cross 5 

Louis Duncan J) 

Louis Bell 2 

Wm. Stanley 2 

T. A. Edison 2 

C. F. Brush 1 

M. I. Pupin 1 


W. A. Anthony 298 

F. B. Crocker 272 

Jas. Hamblet 240 

D. C Jackson 28 

Louis Bell 15 

H. J. Rvan 15 

CO. Mailloux 14 

C. P. Steinmetz 13 

A. KRohrer 11 

Wm. Stanley 1« 

R. H. Pierce » 

Elisha Gray 8 

Carl Bering 8 

Elihu Thomson 8 

T. A. Edison 7 

G. A. Hamilton 7 

P. Benjamin. ... 6 

liouis Duncan ... 6 

W. F. C. Hasson 6 

E. L.NicholB 6 

W. L.Robb 6 

W. E. Geyer 5 

E. W. Rice, Jr 5 

Jos. Wetzler 5 

Townsend Wolcott 5 

B. J. Arnold 4 

C. F. Brosh 4 

J. J Carty 4 

E. J. Houston 4 

M. 1. Pupin 4 

A. Schmid 4 

Edward Caldwell 3 

C. L. Clarke 3 

C. E. Emery 8 

E. E. Higgins 3 

H. W. Leonard 3 

T. D. Lockwood 3 

T. C. Martin 3 

R. W. Pope. 3 

L. B Stillwell 3 

Brown Ayres. 2 

F. L. Pope 2 

G. D. Shepardson 2 

L. L. Summers 2 

Chas. Wirt 2 

A. J. Wurts 2 

A. G. Compton 

A. G. Bell 

J. S. Brown 

C. F. Chandler 

S. D. Field 

C. J.Field 

H. A. Foster 

S. D. Greene 

H. V. Hayes 

J. W. Howell 

W. Maver, Jr 

G. C. Maynard 

F. A. PickerncU 

C.F. Scott 

O. B. Shallenberger 

G. 11. Stockbridge 

E. P. Thompson. 


A. E. Kennelly 323 

W. D. Weaver 279 

C.S.Bradley 264 

W. B. Vansize 250 

N. W. Perry 18 

H. J. Ryan 15 

G. A Hamiltonf 14 

W.F.C. Hasson 14 

Brown Ayres 13 

Nikola Tesla 11 

C. O. Mailloux 10 

H. F. Parshall 10 

Alfred S. Brown 8 

Samuel Sheldon 8 

C. P. Steinmetz 8 

C. C. Haskins 7 

Carl Hering 7 

Jas. I. Ayer 6 

R. 0. Heinrich 6 

Jos. Wetzler 6 

A. C. Crehore 5 

I. II. Famham 5 

R. H. Pierce 5 

W. A. Anthony 4 

R. N. Baylis .*. 4 

Fre<rkBedell 4 

Morgan Brooks 4 

Ijouis Duncan 4 

W. J. Hammer 4 

E. E. Ui^gins 4 

J. R. Lovejoy 4 

T. C. Martin 4 



[May 15, 

FOR MANAGERS.— Continued. 

Thorburn Reid 4 

F. A. Schcffler 4 

F.J. Spraffue 4 

Wm. Stanley 4 

J. J.Carty 3 

F. B. Crocker 3 

R. Eickemeyer 8 

H. A. Foster 3 

C. E. Emery 8 

C. D. Haskins 3 

F. B. Herzoff 8 

C. T. Hutchinson 3 

F. W.Jones 8 

B. Merritt 3 

E. L.Nichols 3 

F. A. Pickemell 3 

E. W. Rice, Jr 3 

C. D.Shain 3 

O. B. Shallenberger 3 

C.Thomson 8 

B.J.Amold 2 

Brown Ayres 2 

J. B. Cahoon 2 

C. R.Cross 2 

C. Cuttriss 2 

T. A. Edison 2 

C.J.Field 2 

Elisha Gray 2 

T. D. Lockwood 2 

R. B. Owens 2 

F. A. C. Perrine 2 

B. F. Thomas 2 

E. P. Thompson 2 

S. S. Wheeler 2 

J. G. White 2 

F. B. Badt 

0. H. Davis 

A. de Khotinsky 

S. D. Greene 

H. V. Hayes 

F. V. Henshaw 

A. S. Hibbard 

W. Hochhausen 

E. J. Houston 

J. W. Howell 


F. P. Little 

L. B. Marks 

W. Mayer, Jr 

G. M. Phelps 

E. P.Roberts 

A. L. Rohrer 

L. B. Stillwell 

G. H. Stockbridge 

F. R. Upton .• . 

E. G. Willyoung 

A. J. Wurts 


Geo. M. Phelps. 

.302 I Geo. A. Hamilton 47 

The Prbsidknt :— The business of the adjourned meeting 
being now completed we will proceed to the regular business of 
the general meeting — the reading of papers. 

Gentlemen, I notice the President's name is down on the pro- 
gramme for the first paper. Before beginning I desire to assure 
you that I appreciate the very high honor you have conferred 
upon me in again electing me to the Presidency of the Instittjte. 
I beg to assure you that it will be my earnest endeavor faithfully 
to discharge the duties thus imposed upon me. I will give you, 
in the way of a brief inaugural address, the Progress of our In- 
STTTUTE During its First Decade. 

[The President then read his address, as follows:] 


Inaugural Address. 


The American Institute of Electrical Engineers is in no 
sense a local organization. It has in view the interests of no 
particular section of country, but, on the contrary, is a national 
body. It represents the electrical profession in all parts of our 
great land, and welcomes into its membership bright and pro- 
gressive men in the electrical profession wherever they may be 

But while the Institute is in no sense a local body, so that no 
city can properly claim as a right the high privilege of having 
the annual meeting held in it, yet there is, perhaps, at this time,- 
a special fitness that the annual meeting, which witnesses the clos- 
ing of the first decade of our association, should be held in the 
City of Brotlierly Love, where the Institute had its birth. 

The International Electrical Exhibition, held in 1884, in Phila- 
delphia, under the auspices of the Franklin Institute of the State 
of Pennsylvania, was called together at an exceedingly favorable 
moment. Eight years had elapsed since the Centennial Exhibi- 
tion of 1876, in Philadelphia, had sown broadcast the germs of 
public interest in electricity, and thus laid the foundation for a 
belief in the bright promises of the electric future. These 
germs, carried to all parts of the land, were beginning to bear 
fruit, and a body of earnest and intelligent workers had sprung 
up on all sides, so that our comparatively limited knowledge of 
electrical science was markedly increased, although in an ex- 
tremely irregular and unsystematic manner, 



Between 1876 and 1884, nearly a decade, the work done in the 
electrical field was necessarily of a pioneer and independent 
character. The great principles of the science, already diflcov- 
ered and annonnoed, were bnt vaguely understood, and needed 
the practical man to carry them into actual commercial use. To 
a great extent, each investigator trod the path of discovery alone, 
gropingly penetrating into the regions of the unknown, unac- 
companied by his fellow investigator, and often, indeed, uncon- 
scious of his existence. Had this early work been properly 
organized, much of the labor expended in going over ground 
already trodden might have been saved, but it is by no means 
clear that this labor was in vain for the weal of the electric 
future; for, truths thus repeatedly wrested from nature and 
established again and again by independent investigators, cannot 
be too highly prized. 

In our nineteenth century activity, events move rapidly. In 
less than a decade from the time of the Centennial Exhibition of 
1876, namely, in 1884, the time had come when the advantages 
of congregation as opposed to segregation were to be demon- 
strated ; when the lonely investigator was to be brought into con- 
tact with his brother toiler and taught the advantages of organized 
work and a free exchange of ideas. 

Happily, the International Electrical Exhibition in Philadel- 
phia of 1884, already alluded to, brought together the workers in 
electricity both in this country, and, to a certain extent, in other 
parts of the world, not only during the Exhibition itself, but 
especially during the completion of the buildings and the arrange- 
ment of the exhibits. The varied exhibits thus brought together 
from all sides were a revelation to these hitherto independent 
workers, and showed them, from what had already been accom- 
plished by electrical science, what might reasonably be expected 
in the near future. The stimulus, so excited, culminated in the 
organization of the distinguished body I have now the honor of 

At the same time, the U. S. Government appointed a United 
States Electrical Commission authorizing it to conduct a National 
Conference of Electricians in Philadelphia during the progress 
of the International Electrical Exhibition. Fortunately for the 
cause of electrical science, the Commission after due deliberation 
determined to appoint as members of this Conference not only 
those investigators in the physical laboratory and lecture room, 

18d4.] PR00RB88 OF TBE INSTITUTE. 277 

the college and university professors, whose labors have always 
proved of such great value to the world's weal, but also those 
equally important investigators, the inventor and actual worker 
in the commercial electrical field, whose knowledge of principles 
is based on actual experience ; a class that proves the correctness 
of its ideas by subjecting the test of actual trial on a 
commercial scale. 

There was thus convened in 1884, in the city of Philadelphia, 
a notable gathering of men who had long toiled in the electric 
field, both in the so-called pure sciences and in the applied 
sciences, and I feel sure that each class recognized the fact that 
it learned much from the other. 

In this notable assembly of electrical students, our American 
Instittte of Electrical Engineers originated. I may be 
pardoned if I briefly review the facts attending its inauguration. 

The first step was the circulation in April, 1884, by Mr. N. S. 
Keith, of a paper asking for signatures for the purpose of 
organizing a National Electrical Society, for affiliation with 
sister societies ; for the possession of a library, the institution 
of original research ; protection from unfavorable legislation ; 
the settlement of disputed electrical questions, and the exchange 
of volumes of its Transactions with foreign and other electrical 
scientific societies. A preliminary meeting was called on April 
15th, 1884 in the city of New York, at which a series of resolu- 
tions were passed, and a Committee of Organization appointed to 
call a meeting, which was subsequently held on May 13tli, 1884, 
when rules of order were adopted and oflicers elected. The first 
regular meeting of the Institute was held in Philadelphia, 
October 7th and 8th, 1884, in one of the Exhibition Buildings in 
West Philadelphia. 

From this small beginning our Institute has assumed its pres- 
ent proportions. Its growth was, at first, uncertain, but its 
vitality was undoubted, and its present rate of increase is fully 
equal to that of our English cousin, viz., the Institution of Elec- 
trical Engineers. I append a curve showing the membership of 
both bodies at different dates, and although the British Int^titu- 
tion had the start, and has the advantage of us in membership, 
yet I look forward in the near future to a membership in our 
lx)dy that will be fully on a par with theirs. 

I think it would be difficult properly to estimate the good that 
has accrued to electric science, not only in this country but also 



[May 16, 

in the world at large, from a properly organized association of 
specialists in a practical branch of science like that of electricity. 











































































Total Membership at different times of the 

, British Institution of Electrical Engineers, and 
American Institute of Electrical Engineers. 

If we can properly trace, from the circumstances attending a 
single electrical exhibition and series of conferences held in 

1894.] PR0GBB88 OF THE INSTITUTE. 279 

Philadelphia in 1884, a great awakening in the field of electric- 
ity, what must have been the influence for good, exerted by a 
body like oars, which I think I am correct in -saying inclades all 
the distinguished practical electricians in this country. 

In order to inquire what has been the nature of this influence, 
let us briefly examine the history of the American Institute 
ofElsotbical Engineebs during the ten years that have elapsed 
since its foundation, and see whether, in the first decade of its 
existence, it has duly availed itself of its great opportunities. 
Let us inquire what great inventions and investigations have 
been made by its members. I think that as a result of these 
inquiries, you will agree with me that our Institute has nobly 
fulfilled the expectations reposed in it, and that electricity is 
much further advanced than it would have been had the 
American Institute of Electricax Engineers never been 

A glance at the Transactions of the Institute will show the 
extended and valuable character of the work of its members. 
This work embraces notable inventions, extended commercial 
applications, and valuable researches ; as, for example, researches 
in high frequency discharges; the development of alternating 
current apparatus for electric welding, and for the transmission of 
power ; improvements in continuous current apparatus ; improve- 
ments in the practical applications and control of electric motors 
for traction, mining, manufacturing and other purposes; im- 
provements in telephony and telegraphy; improvements in 
the application of electricity to various chemical processes; 
improvements in designs for electric machinery ; improvements 
in electric lighting apparatus of various descriptions, and develop- 
ments in electro-therapy. 

The work of the Institute as a body has also been of a broad 
and valuable character. I have already pointed out to you, in 
my inaugural address of last year, the valuable contribution the 
Instttute made to the Chicago Congress and Exhibition of 1893. 
Since that time, as you are aware, organized work, under the 
auspices of the Institute, has been and is being carried out in 
different parts of the country, as well as in England, for the 
completion of some of the work the Chicago Congress was 
obliged to leave incompleted ; viz., the determination of suitable 
standards of light and of illumination. 

Another action of which I think the Institute may be proud. 


has been its provisional adoption of the well known names of 
gilbert, oersted, gauss and weber, for the most important quan- 
tities in the magnetic circuit, thus filling a well defined void in 
the practical development of the dynamo, motor, and magnets 
generally. These names have already been favorably commented 
on in Europe, where they have been embodied in at least one 
standard text-book. 

Up to this date there has been much uncertainity as to the 
meaning which should properly be attached to the very import- 
ant term " inductance." It was hoped that the Chicago Con- 
gress would decide this question, but, as this hope was not 
realized, the Institute, by appealing to the prominent affiliated 
institutions in Europe, has been enabled to ascertain the consen- 
sus of opinion upon this matter among electrical engineers all 
over the world, and has to-day adopted the meaning of " induc- 
tance " as a " Coefficient of Induction," this being the world's 
majority verdict, so far as has been possible to obtain it without 
the aid of an International Congress. It has also adopted the 
word " reactance " for that quantity in alternating current cir- 
cuits, whose square added to the square of the resistance is the 
square of the impedance. 

It would be ungenerous in me in thus reviewing the causes 
which have led to the development of electrical science in this 
country, to fail to mention another potent factor. I refer to the 
electrical press. I recognize its power and tlie good it has ac- 
complished in spreading broadcast over the country, not only to 
the members of the Institute, but to all interested in electrical 
progress, the knowledge of every great advance made in electric 
science. In a certain sense, however, the electrical press sup- 
plements the influence of the Institute, because the press, un- 
like the Institute, cannot bring electrical workers together, but 
can only guide and disseminate the conclusions they have 

The growth of the electrical press has kept pace with the 
growth of electrical science. In 1876 the power of the press 
was comparatively feeble. The Exhibition of 1884 caused, per- 
haps, as great an increase in the power and influence of the press, 
as it did in the devolopment of the science of electricity itself, 
and, great as has been the marked improvement in electrical 
science, as demonstrated by the Chicago Exhibition of 1893, I 
think close observers will agree witli me that such progress has 

18^] PROGRms OF THE INSTtTUTt!. ^1 

been fully equalled by the wonderful improvement in the elec- 
trical press of our country. 

There is another association of electrical engineers of the 
same high standing, and governed practically by the same prin- 
ciples as those of the American Institute oj: Electrical En- 
gineers, and this is our affiliated association, the Institution of 
Electrical Engineers, with its headquarters in London, England. 
Like our association its membership contains the leading electri- 
cal engineers and experts both in the country in which it is 
located, and in the surrounding countries. 

France has established a somewhat similar body in her Soci6t^ 
Internationale des filectriciens, located in Paris. This society 
has the same general characteristics as the American and English 
societies, and, like them, publishes regular transactions of its 
proceedings. In Germany, there is the Elektrotechnischer 
Verein and the Physikalisch-Technische Reichsanstalt. 

Although there* are electrical societies in other parts of the 
world, notably in Italy, and Belgium and Australia, yet in none 
of these countries is to be found that organized effort and con- 
centration in one cenlatil body of the electricians from all parts 
of the country, as is so markedly seen in the United States, 
England, France and Germany. 

It is, I tliink, a significant fact, that the countries in which 
there has been so marked a progress in electrical invention and 
engineering, are those which possess the advantages of this com- 
bined effort on the part of all its electricians. The reason is, I 
think, evident; under these circumstances, there exists the 
enthusiasm which comes from properly organized effort; 
the rapid progress which is encouraged by friendly rivalry and 
the incentive to increased and continued effort, bred of healthy 
competition. I think I can safely assert that America, England, 
France and Germany owe much of their marked advance in 
electrical science to the existence of their organized bodies of 
electricians, such as is found in the American Institute of 
Electrical Engineers, the Institution of Electrical Engineers, • 
the Society Internationale des filectriciens, and the Elektro- 
technischer Verein, and I feel sure from the great number 
of able electricians of Italy, Switzerland, Belgium, Russia, India 
and other parts of the world, that the progress made in tliese 
countries, a progress which is confessedly great, would be still 
greater if they but tried the advantages of electrical work con- 
ducted on the co-operative plan. 


It may be advantageous here to review some of the advantages 
of membership in snch learned associations, as, for example, the 
Instfiute in which we are the most interested. Among the 
many advantages are the following : concentration of effort ; in- 
creased mentality excited by generous rivalry ; systematic explora- 
tions into the domains of the unknown ; a tacit agreement as to 
what shall be regarded as the standard of good work ; the practi- 
cal establishment of a high court of last resort by whom all dis- 
puted technical questions in electrical engineering shall be 
finally settled ; the removal of electric work from the region of 
guesswork to that of certainty, permitting results to be as surely 
predicted as in other sciences, and, consequently, an increased 
stimulus to the successful investment of capital in electrical en- 
terprises ; the reduction of misdirected eflEort by the promulga- 
tion of information concerning what has been attempted or 
achieved in any direction ; and last, but not least, the means of 
establishing a rapid intercommunication of ideas between differ- 
ent parts of the country to others. 

As to the privileges of membership in our association, a mem- 
ber in any part of tlie country, whether in Maine, Florida, Illi- 
nois, or elsewhere, can, after submitting a paper to a committee 
appointed by the Institute for that purpose, have it read simul- 
taneously at the New York and Chicago meetings, and thus not 
only derive the advantages which come from the broad dissemi- 
nation of his ideas over the country, but -can also have those de- 
rived from criticism by those best adapted to judge and discuss 
them. Instead of being obliged to wait and wonder if his re- 
sults are valuable or correct, or instead of being forced to en- 
deavor to solve such questions for himself, he is now, by means 
of the powerful machinery of our association, enabled to hear 
in a very short time the opinion of those best suited to sit in 
judgment on his work. 

We are naturally and properly proud of the progress shown 
by our Institute in the first decade of its existence. I ask you 
now in all seriousness, how has this progress been assured? 
Clearly by the establishment of a central, organized body, as 
distinguished from separate, independent, and possibly antago- 
nistic bodies; by the establishment of a central body which 
derives its authority from a membership extending over the 
entire country. Is it credible that independent, disconnected, 
and possibly antagonistic societies, located in as many separate 

1894.] PR0GRB88 Of THE INBTlTUTB, ^88 

cities as there are groups of members sufficient to form separate 
societies, can hope to accomplish as much good in so short a time 
as has been accomplished ? Would not the disintegration of our 
Institute prove to the electrical engineers of this country little 
short of a calamity 'i Might not the establishment of separate 
organizations result in mutual jealousies and intense sectional 
feeling, and, consequently, in a tendency to the continuance 
of errors once contracted ? Partisanship and intelligent scien- 
tific work, in the nature of things, have nothing in common. 
The true scientific instinct is shown in the desire to know the 
truth for the truth's sake, and the true electrical engineering in- 
stinct is to accomplish the best work in the most economical 
manner possible. I feel sure you will agree with me that to 
ensure the greatest success, there must of necessity be a central 
governing body, viz., the Council of the Institute, deriving its 
authority from a membership extending all over the country, and 
vested with the power of speaking authoritatively for the 
Institute between the periods of its recognized official meetings. . 

In a country like ours, in which distances are so great, a diffi- 
culty exists in all our members attending the meetings of a cen- 
tral body, no matter where such meetings might be called. This 
difficulty is real, and like all geographical difficulties, cannot 
readily be solved. I think our association has, however, to a 
great extent, partly solved it by encouraging simultaneous meet- 
ings in all parts of the country where the same paper can be 
read and discussions had thereon, yet at the same time, holding 
the governing body, the Board of Managers or the Council of 
the Institute, responsible for the proper direction of its work. 
That all local meetings must be amenable to the organic law of 
the Institute, be that law what you may choose to make it, I 
think needs no discussion. I am glad to say that already, under 
due authority of the Institute, local meetings have been estab- 
lished in the city of Chicago, and I trust there may soon be 
other similar meetings held in all other great centers of 
population where our membership will warrant it. 

Such, I think, are some of the advantages of organization 
under a central body as opposed to organization under separate, 
independent bodies. They are, briefly, the advantages of concen- 
tration as opposed to those of diflEusion ; of directed, organized 
efifort as opposed to unorganized, undirected effort. To argue 
in favor of the latter would be, I think, to deny the advantages 


of a central government, like our national government at Wash- 
ington, with its representation from all the various States 
of the Union, and to revert to the condition of states sovereign- 
ity, an un-American and altogether untenable position. 

As I look over this assembly of distinguished electricians, I 
am particularly impressed with this thought ; viz., our average 
member though old in actual experience, is, nevertheless, seldom 
hoary in years. There must be something in electricity, though 
what it is I would not venture to say, which attracts the younger 
and more vigorous members of our race to its study; Percliance 
it may be that in this mysterious force, there exists some linger- 
ing traces of the long sought for " fountain of youth ;" but, be 
it what it may, I find in the fact that such comparatively young 
men have been able to do so much for the world's weal in a 
special science, a bright promise of what they may be able to 
accomplish before their tasks are completed. 

Such is the record of the past ten years of our iNSTrruTE ! 
. What will be the history of its next ten years ? I look forward 
confidently to a still greater and more marked progress than that 
wliich has characterized it during the first decade of its exist- 
ence. I believe that during the next decade its standing will l)e 
sucli that all notable achievements and discoveries in the elec- 
trical field in this country will either originate, in this body, or 
be carried out under its direction, and that the American Insti- 
tute OF Electrical Engineers will be the acknowledged center 
of the industry and art it now so ably represents. 

But while I believe I see so bright a future for our American 
Instffute of Electrical Engineers, I must not be unmindful 
of the fact I have so earnestly endeavored to point out, viz., the 
advantages to be derived from co-operation, and that our Insti- 
tute is only one of several such organizations in diflEerent parts 
of the world, and that the highest purposes of the science and 
art in which our interests are so closely centred, can only be best 
realized by the most cordial sympathy and hearty co-operation 
with all associated societies and their members wherever they 
may be. 

The President : — The next paper " On the Subdivision and 
Distribution of Artificial Sources of Light," will be read 
by Professor Anthony. 

A paper /resented at the eieventk General Meet- 
ing of the American Institute of Electrical 
Engineers, Philadelphia^ May isth^ 1894. Presi' 
dent Houston in the Chair, 



It is a well recognized principle that to illuminate evenly a 
given area by means of an artificial source, it is necessary that this 
source should consist of numerous small sources distributed over 
the area. In carrying out tliis principle it is usual to divide the 
area to be lighted into squares, and place a lamp in the center of 
each square as shown in Fig. 1 where each lamp is represented by 
the sign x. In order to study the distribution of light by this 
arrangement of lamps I have computed the illumination at the 
central point of the figure due to the lamps situated upon the 
boundaries of each of the squares represented by the dotted 
lines, the illumination produced by the lamps on the smallest 
square be taken as unity. The following table gives the values 
up to the twelfth square, twice the number represented in Fig. 1, 
and corresponding, therefore, to an installation in which four 
times as many lamps are used. 
















, 3 













1 6 





1 7 





' 8 





















Column I gives the designating number of each square count- 
ing outward from the central point. Column 11 gives the illu- 




[May 15, 

raination at the center due to the lamps located on each bound- 
ary. Column III gives the total illumination at the center due 
to the lamps included within and upon each boundary. Column 
IV gives the number of lamps situated upon each boundary. 
Column V gives the total number of lamps. 

It is seen from the table that the twelfth series which consists 
of 92 lamps gives at the center less than 7 per cent, as much 
light as the first series of four lamps, and contributes only about 
two and one-half per cent, to the total illumination at the center. 
This arrangement of the lamps does not give an even distribution 
of light over the entire area, as will be evident from a considera- 


*«.-•-»» — ♦«■- - 


*" -X- 

-K- -H^- - 

■ih- -» 




Fro. 1. 

tion of the illumination upon the outside boundaries of tlie space. 
It is evident that the point b at the corner of Fig. 1 receives one- 
fourth as much light as it would do if it were the center of an 
area four times as large, and lighted by four times as many or 
576 lights. But the illumination at the center of such an area as 
seen by the table is 2.905. The illumination at b is, therefore, 
2.905 -^ 4 or .726, while the illumination at a from the sixth line 
of the table is 2.363. The illumination at b is then less than one- 
third that at A. At c the illumination is evidently but little 
more than half that at a. Points located between the center and 


outside would be illuminated to an intermediate degree, but after 
leaving the outer boundary the illumination would rapidly ap- 
proach that at the center of the figure. I am considering always 
points of least illumination in any region, that is, points situated 
as far as possible from any lamp. It is evident, therefore, that 
to obtain a uniform distribution of light, the lamps must be con- 
centrated toward the outer boundary of the space instead of be- 
ing placed at equal distances throughout, as in the figure. 

But the most interesting questiofi connected with this matter 
is : what is the effect upon the uniformity of the illumination of 
grouping the lamps in clusters or using larger lamps at fewer 
points? It is evident that whatever the candle power of the 
lamps or their distances apart in a distribution like that repre- 
sented in Fig. 1, the relations represented in the table will 
remain unchanged. It is evident also that the illumination at 
the central point will be proportional to the intensity of the in- 
dividual sources (if lamps are placed in clusters each cluster is to 
be considered as a source) and inversely to the square of the 
distance between the sources. 

This illumination is, therefore, given by the formula 

where f is a constant depending on the units employed, 8 the in" 
tensity of the individual sources, d the common distance between 
them, and C the quantity in column iii of the table correspond- 
ing to the number of sources as found in column v. 

Compare the illumination at the center of an area lighted by 
576 lamps with that at the center of the same area lighted by the 
t*ame lamps arranged in 144 clusters of four lamps each. If 8 and 
(I represent the intensity and distance in the first case, 4« and id 
will represent the corresponding quantities in the second case. 
Cm the first case is 2.905 corresponding to 576 sources. In the 
second case, for 144 sources C is 2.363. The relation sought is, 

K ~ 2.363 
4 d^ 

= .813 

KS 2.905 

The light at the central point with the fewer sources, is only 
81 per cent, that obtained under the first arrangement. Other 


[May 15, 

pointB of minimum illumination will suffer in like manner. On 
the other hand, points near the clusters of lamps will be much 
more strongly illuminated than corresponding points near the 
single lamps of the first arrangement. 

If it be required that the illumination at no point shall be less 
in the second case than in the first, it will be necessary to increase 
the intensity of the sources nearly 25 per cent, or make the 
clusters consist of five instead of four lamps. 

Again, suppose an area liglited by 04 sixteen c. p. lamps distri- 
buted as in Fig. 2. It is re(|uired to substitute 1() lamps of larger 
caudle power distributed as in Fig. 8, and fulfilling the condition 

jjf_ .-* >^_.^)^_ ._x.. .-H-. -M iL 

J 1— ^ ^ ^ ^ 

% *- -*- -X---it- -K---*|C * ! I 

J 1 j ^ 1 {- 

lc if. If X--K---* ;k i I ' 

* t X *--¥ » X ^c I ; J ; 

j 1 1 ! 1 j — ; u- — 1 1 u 

I • I • I I I I I I I 

* « * *- -X « * X j I I I 

-j \ 1 1 1 'r— ;(c * ^ ^ 

« X *---x — X- --i x * \ I 

J — I \ — '^ — ! 1 

X >- — ¥,-■ -M--M-- -n- -* X [ [ 

j^ [ — ^ ^c -K •* 

« -M « -K— -*<- -H - X -*C 

Fig. 2. 

Fig. 8. 

that the minimum illumination shall be no less in the latter case. 
If X be the candle power of the larger lamps, we have : 


X 1.511 = V' X 2.046 

... ,, 2.046 ^^ ^ 

From which it appears that the total candle power must be 
increased 35^ per cent. If the 16 candle power lamps consumed 
8.5 watts per candle, the larger lamps to compete with them 
should consume less than 2.6 watts per candle. 

It will be noted from the two examples given, that the loss 
from reducing the number of sources in a given ratio is less 
when the number is large. In other words, large lamps, or clus- 
ters of lamps, can be more economically used for large, than for 
small areas. 


An inspection of the table will show, that while a given area 
may be lighted satisfactorily by 16 clusters of four lamps each, 
an area one-fourth as large, lighted by four clusters at the same 
distance apart, would not be as well lighted with six lamps to 
the cluster. It will be seen also that the larger the area, the 
further apart may lamps of the same candle power be placed. 
For example a room 40 feet square with 16 lamps 10 feet apart, 
is fully as well lighted as a room 16 feet square with four 
lamps eight feet apart. 

Let us compare arc and incandescent lights on the same basis, 
that the minimum illumination shall be the same under both 
systems. First, I must say that the efficiency of arc lights has 
been greatly overrated. Instead of being ten times, it is rarely 
three times, and often only one and a half times that of an in- 
candescent lamp.^ This is for the naked arc. For indoor illu- 
. mination, ground or opal globes are nearly always used, and these 
cut off fully half the light.* This leaves the efficiency at the 
most 1.5 times that of the incandescent lamp. The power re- 
quired for a 16 candle incandescent lamp is 50 watts, and for a 
full arc lamp 450 watts. The arc lamp must, therefore, replace 
nine incandescents. Assuming that the lamps are distributed as 
described in this paper, the table shows that if four arcs take 
the place of 36 incandescents, their efficiency as compared with 
the incandescents must be 1.823, and with a relative efficiency of 
only 1.5, the arc lamps would not light the space as well as the 
incandescents. If 16 arcs take the place of 144 incandescents, 
the ratio of the efficiencies required is 1.56, and arcs at 1.5 are 
still not equal to the incandescents. If 64 arcs take the place 
of 576 incandescents, the ratio of the efficiencies becomes 1.42, 
and arcs at 1.5 would be an improvement on the incandescents. 
It comes then to this, that unless the area to be lighted is so 
large as to require about 500 incandescent lamps distributed uni- 
formly over it, the use of full arc lamps requiring the same 
power, will leave some parts of the area less brilliantly lighted. 
' If we could make small arc lamps of the same efficiency as 
the full arc — by full arc I mean the so-called 2,000 candle lamp 
consuming about 450 watts — we could improve somewhat upon 

1. See " Eflaciency of Artificial Methods of Illumination." Dr. Nichols : 
Transactions, vol. vi., p. 171. 

2. ** Loss of Light from Use of Globes with Arc Lamps." George D. Shepard- 
son: J^Slee^rical World, vol. xxiii., p. 287. 


the result as obtained above. But the fact that the mechanism 
of a small arc lamp costs just as much as tliat of a large one, and 
that edch small arc will require as much care and attention as a 
large one, would place a limit upon the subdivision of the arc 
even if the efficiency could be maintained. And here I wish to 
enter a protest against the assumption that I often find in discus- 
sions of this subject, that the sfhcaUed 1,200 and 2,000-candle 
power arc lamps are 1,200 and 2,000-candle lamps. There is no 
450 watt arc lamp in use that will measure 2,000-candle8 in the 
direction of greatest intensity ,'and compared with other artificial 
sources for general illumination, that is measured as other sources 
are measured, there is no 450 watt lamp that will give, when 
surrounded by a plain glass globe, 500 candles. 

In a linear distribution, as in street lighting, the arc is at a 'still 
greater disadvantage. Remembering that nine 16-candle incan- 
descent lamps can be run with the power required for one 460-' 
watt arc, it is seen that the arcs must be nine times as far apart 
as incandescents consuming the same power, and to give the same 
minimum illumination nmst be 81 times as intense, or about 
1,300 candle power. But in no arc lamp as used for street light- 
ing, do the rays proceeding toward the most distant points to be 
illuminated, reach more than one-fourth this intensity. In my 
way of thinking, the location of arc lamps at intervals of 1,000 to 
1,600 feet as they are often seen in pretentious country villages 
aud suburban places is an entire waste of money. A little spot 
50 to 100 feet in diameter under each lamp is brilliantly lighted, 
while the more distant points are in darkness all the more pro- 
found from the loss of sensitiveness of the eye when in the strong 
light. Incandescent lamps at intervals of 100 to 200 feet, which 
could be run by the same power, would give a far better illumin- 

Of course, in deciding between the use of arc and incandescent 
lamps in any special case, there are other questions to be con- 
jsidered besides that of the power required to operate. Practical 
questions of installation may outweigh all others. The consider- 
ations of these is foreign to this paper. The question I have 
considered is purely one of efficiency, and in treating that 
question I have assumed that every part of a space to be lighted, 
needs the same amount of light. I have omitted from the con- 
sideration all effects of reflection from ceilings, walls, or reflec- 
tors purposely provided, as these are too various and depend too 


much upon the conditions in each special case to be introduced 
into a general discussion. My main object has been to point out 
to just what extent the general illumination of a space is affected, 
other things being equal, by the use of large in the place of small 
sources using in the aggregate the same power, and I trust the 
figures and illustrations I have given may be found useful in 
considering the special cases that may arise. 
Vineland, N. J.. April 28th, 1894. 



Mr. Nelson W. Perry : — I would like to ask in regard to the 
statement that no 450 watt lamp will give, when surrounded by 
a plain glass globe, 500 candles, what it means ? There have 
been so many thousand measurements of the intensity of arc 
lamps that Imve almost universally shown an intensity in the 
plane of maximum illumination between 750 and 1250 and even 
more, that it would seem that they could not all be wrong. 
Most of these measurements were made with lamps without 
globes probably. Now, if we assume 1000 c. p. as an average of 
all of these determinations without globes, we must assume that 
Prof. Anthony's statement if true must mean that clear glass 
globes cut off at least 50 per cent, of the light in order to bring 
it down to 500. This of course is absurd. 

Prof. Anthony: — I think you misunderstood the statement 
there. The statement is in tne direction of the most distant 
point to be illuminated. 

The President: — Is that made by the short arc or the long 

Prof. Anthony : — The long arc 450 watt lamp. That is in 
the direction of the farthest point to be illuminated. It would 
be not more than ten degrees from the horizontal line. The 
illumination of any arc lamp in that direction is very small. 

Mr. Kennelly : — ^While the figures that Prof. Anthony gives- 
are no doubt true in the open air, without moon or star light ; 
that is to say where there is no reflection ; yet within doors the 
circumstances of reflection from walls and ceilings, would so far 
modify the practical conditions of the problem, that the conclu- 
sions to be drawn from the paper will surely undergo great 
modification in consequence; and while no doubt the general 
proposition is true that to get the most uniform and the least 
minimum illumination at any point, you should place a thousand 
candles in 1,000 candles and not have it in one lamp, still the 
effect of reflection from walls and ceilings, will so far modify 
any preconceived notions that we may have upon what should 
be the best luminous distribution, that everything would largely 
depend upon the particular circumstances of each case. 

The President : — I must confess to considerable surprise at 
the figures reached by Prof. Anthony. I do not doubt but that 
as a careful scientific man he has trie facts of actual measure- 
ment to warrant the correctness of these conclusions. I would 
say, though, that such a very small economy of light for an arc 
lamp is quite at variance with the experience 1 have had in the mat- 
ter, and is absolutely inconsistent with our ideas of the relations 
existing between temperatures and the power of emitting light. 
The temperature of an arc is immensely higher than that of an 
incandescent filament at any temperature at which it would be 
practicable to run the filament, and to get so astoundingly small 
an economy out of an arc lamp shows that there must be 'either 

1894.] DI80U88I0N, 398 

some peculiarity of measurement, or something wrong in our 
preconceived ideas as to the relation which ought to exist be- 
tween candle power and temperature. I do not think it fair to 
measure the light giving power of an arc in a horizontal direc- 
tion and base conclusions on that. It is fair enough to take that 
in an ordinary gas flame or in an incandescent light where this 
direction is far from being its position of least emciency. I do 
not think it is fair to take it in the case of an arc light. I was 
particularly induced to ask whether you were running with the 
long arc or the small arc since it struck me at first that possibly 
the error might come from the shading of the positive crater by 
the projection or nipple on the negative carbon. The figures 
surprise me very much. I feel sure that it will be quite a 
surprise to those interested in arc lighting in the country to learn, 
if I am correct in my understanding, that you do not get more 
than one amd one-half times out of the arc than out of the in- 
candescent. Still, if true, it is very well worth learning. 

Mr. Steinmetz : — I think the figures are not very far from 
true. When the 2,000 candle power arc light got this name, it 
was given to it because if everything is adjusted carefully, as it 
can be done in the laboratory, then the maximum intensity is 
about 2,000 candles, but the spherical intensity is only little 
more than one-third as high, that is, 700 candles, and taking 
into consideration, that a part of the light is shaded off by the 
glass globe, we get not very far from 500 candles as the mean in- 
tensitv of the covered arc. Still from another side you can ap- 
proach the same result : 

The brilliancy of the arc is that of boiling carbon. The 
brilliancy of the incandescent lamp filament, that is, the candles 
per watt, is less. But, increasing the temperature by raising the 
voltage, increases the brilliancy, until the carbon filament evapo- 
rates. Now, immediately before this, the brilliancy must be 
about the same as that oi the arc. Photometric teste of incan- 
descent lamps at seven to eight times their rated candle power 
give brilliancies of from 1 to 1.2 candles per watt, and seem to 
point towards a maximum value of about 1^ c. p. per watt. The 
spherical brilliancy of very large arcs was observed as 1.5 to 1.7 
candles per watt. 

The above stated data of 2,000 maximum or 700 spherical 
candles for the ordinary 450 watt arc gives a brilliancy of 1.55 
candles per watt, so that, estimating the light absorption of the 
glass globe as 30 per cent, we get the figures given by Prof. 

Hence the name " 2,000 candle power arc " only refers to the 
maximum intensity of the naked arc in the most favorable direc- 
tion. A more proper way to rate arc lamps would be, not by 
the candle power, but by the watte consumed. I think that is 
quite extensively done now. 

Mb. Clayton W. Pike: — I understand Prof. Anthony's 


figures are about 500 candles spherical when the glass globe is on. 

I remember making a number of experiments on 1,200 candle 
power lights without any globe, of the spherical intensity, and 
m every case we ran below 450 candles. If we change from 
the 1,200 to the 2,000 and also bring in the correction for loss 
from the globe, we shall find those figures correspond very 
closely with Prof. Anthony's. I have done that on a sufficient 
number of arc lights to enable me to feel sure that those figures 
are correct. 

Pbof. Anthony : — If I may put a figure on the blackboard : — 
(making a sketch. Fig. 4) measuring the intensity of the light 
from an arc lamp at various angles from the horizontal down- 
ward, we obtained results which when plotted on a system of 

Fio. 4. 

polar coordinates gives a curve like a, J, <?, rf, where oa, o J, oc, 
etc., represent the intensities in those directions. The maximum 
intensity occurs at 45 or 50 degrees below the horizontal, and 
from that point toward the horizontal it decreases very rapidly, 
until along the horizontal the 450 watt arc will rarely measure 
more than 300 candles. It is usual to take as the mean intensity 
of the arc light the mean intensity in the lower hemisphere be- 
cause it is the lower hemisphere tliat we wish to illuminate in all 
ordinary use of the lamp. Since the light in the* upper hemi- 
sphere is extremely small, the mean intensity for tne lower 
hemisphere is mucli greater than the mean intensity for the 
entire sphere, but even in the lower hemisphere the mean inten- 
sity is not above 500 candles. 

ISH.] DI8GUS8WN, 20$ 

The Pkesident: — ^At what height did you estimate the average 
height of the arc ? 

Prof. Anthony: — These are candle power measurements 
made on a photometer. The horizontal m^tensity would be a 
horizontal line. 

The President : — You are not considering then the question 
of illumination at all ? 

Prof. Anthony: — In this case, in determining the candle 
power, we simply measure it on a horizontal line as so many 
candles and so on as you go down. At 46 or 50 degrees there 
is a maximum, and the measurements will sometimes run to 1,500 
or 1,700 candles. On good 450 watt long arc lamps I never 
obtained but one measurement out of thousands I have made, as 
high as 2,000 candles. 

The President: — That probably is near the crater, say, on on& 

Prof. Anthony : — Very likely. 

The President : — I do not yet see why you call that the 
maximum intensity. That is not the maximum intensity ; else I 
do not understand. The horizontal line — did I understand you 
to call that the maximum intensity ? 

Prof. Anthony : — No. At some 45 degrees below the hori- 
zontal, is the line of maximum intensity. At the horizontal 
line it would not be more than 300 candles. 

The Secretary : — Then the practical efficiency of the lamp 
would depend very largely on what purpose that lamp was in- 
tended for. If it was intended for the illumination of a park 
or any large open space, it might be well to have it up at a cer- 
tain height, while for practical purposes, if the illumination was 
required on a horizontal plane opposite the arc it would be com- 
paratively inefficient. So that the practical result will have to 
depend largely on the purpose for which the lamp is designed. 

Mr. Francis E. Upton : — A little apart from the subject of 
arc lamps, I would like to say, that I am very glad to see that 
Prof. Anthony has made an effort at the distribution of light, 
which, as I understand, is the title of this paper. A number of 
times I have had that subject brought before me, and I know 
that it is one of the most puzzling subjects which can be pre- 
sented. The tconditions vary so, as Mr. Kennelly mentioned, 
about ceilings and walls, that the question of proper distribu- 
tion of light is one which it is very difficult to answer in general 
terms. There is one point in distribution which I have noticed, 
which probably many of you have observed : that is the fact, that 
in the illumination of a given space, the whole aim should be 
not to spot the lighting, so that the eye will not lose its sensitive- . 
ness by being dazzled by a bright spot. It is well known to those 
who have to do with lighting, especially with the incandescent 
lamp, that rooms can vary two or three-fold in their rate of illu- 
mination ; that is the absolute rate of illumination without being 


noticed if the eye has only darkness to compare the liojht with. 
1 wish Mr. Stieringer were here, as he is a master of the art of 
illumination. He put in practice one of the most successful illu- 
minations in this country ; that was at the exposition at Louisville 
some years ago. At that place he distributed his lights with the 

Eower to prevent anybody from putting an arc lamp in the 
uilding, or from using any light, grouped in clusters, near the 
ground. The result was that he was able to illuminate a large 
exhibition building there, so that it looked brilliantly lighted 
with a very low grade of absolute illumination, because there 
was no one spot which your eye looked at which made the rest 
look dark. 1 feel that there is great room for some good 
means for determining illumination in distinction from determin- 
ing the candle power of the light giving body. There appears 
fo be no good unit for illumination that is thoroughly reliable 
for this purpose, and I think that a discussion of the general 
lines that rrof. Anthony has made in this paper, adds to the 
knowledge of what is meant by the distribution of light, and I 
jQnd it very interesting. 1 think, probably many of you have 
perceived, in going along a street at night and looking into the 
various stores and seeing how much the illumination varies, by 
reason of the mode of placing the lights in those places, how 
much more use can be made out of lamps well placed than out 
of lamps poorly placed. 

The Prksident : — I suppose the photometer you used abso- 
lutely prevented any reflection from the ground. You simply 
measured the horizontal ray. You had probably a shield or 
screen or something to prevent any other light from coming in 
except from that direction. 

Prof. Anthony : — Those measurements such as I have shown 
on the board are made in the photometer room — a blackened 

The President: — Consequently you would lose all possible 
advantage of what you get in actual practice — illumination of 
objects from light thrown from the ground. I cannot believe in 
only one and a naif times the eflSciency of the arc light over the 
incandescent. It is contrary to my experience. I think there is 
something wrong in the method. However, I certainly shall 
know in a little while whether 1 am wrong or not. • 

Mr. K. O. Heinrich : — It is rather surprising that so little 
attention has been paid to the very important and eminently 
practical questions considered by Professor Anthony. If we 
would simply make a distinction between luminosity of a source 
and illumination produced, such perplexing questions as the 
actual candle power of a "2000 candle power" arc would be of 
very minor importance. 

On account of the complication of conditions the illuminating 
effect of a combination of sources of light, such as met with for 
artificial illumination, is almost beyond mathematical computation. 
A practical and successful solution of such problems can be ob- 

1804.] DI8GU88I0N. 297 

tained only through a vast number of observations and measnre- 

The requirements of actual practice are two-fold: First: A 
uniform illumination should be attained, one which comes nearest 
to the ideal illumination of diffused daylight. Second : A definite 
intensity of illumination should be assumed as necessary either 
for the performance of certain work, such as reading, writing, 
drawing, sewing, etc ; for general indoor illumination in theatres, 
halls, etc., and lor outdoor and street illumination. 

It matters little for these considerations what the "candle 
power'' of a source of light amounts to ; for the conception of a 
definite illunjination, this expression is without meaning. It is 
necessary under the above considerations to express the intensity 
of illumination in its own distinct unit. 

Little has been done towards the universal adoption of such a 
unit, although the " metre candle " was proposed for the purpose 
more than ten years ago by Prof. Leonnard Weber, W. H. 
Preece, and Mr. Wybaw, the latter proposing the name " lux " 
for this unit. 

On the authority of Dr. H. Cohn (Breslau) 60 metre candles 
Are sufficient to permit reading with the same facility as in 
diffused daylight. He considers 10 metre candles as a minimum 
illumination from a hygienic standpoint, for the purpose of read- 
ing. Wybauw (M^sure et repartition de I'eclairement. JBvU. de 
la Soc. Beige d^Electr.^ 1885) considers 15 to 25 metre candles 
or "lux" as necessary to permit a fluent and prolonged reading 
of a newspaper, and holds that a minimum of one metre candle 
should be required for street illumination. 

Assuming such or similiar values based upon a unit of illumi- 
nation, all controversy as to candle powers would be at an end. 
Contracts for the illumination of reading rooms, halls, streets, 
43quare6, etc., should specify a required minimum illumination 
in some such unit as above referred to, and it would then rest 
with the expert engineer to accomplish this with the least possible 
amount of mechanical energy converted into light. 

Actual measurements would soon convince us in what bungling 
way illumination is generally carried out. Prof. Anthony's 
remarks in reference to the lighting of pretentious country 
villages and suburban places are very pertinent; they would 
apply equally well to tlie illumination of our city streets and 
squares if it were not for the illuminated shop windows which 
somewhat mitigate the contrast between superabundance of light 
and darkness. 

In connection with this matter I may be allowed to make 
reference to Professor L. Weber's portable photometer, which is 
especially adapted for making measurements of the intensity of 
illumination. This photometer seems little known on this side 
of the Atlantic, ana I therefore give a sketch of its general 
arrangement. See Fi^. 5 and 6. 

The apparatus consists of a tube a about 30 cm. long, which 



can be moved up and down, and swong in a horizontal plane on 
the upright 0. The standard light s, a benzine lamp, is contain- 
ed in a lantern fastened to the right end of the tube a. Within 
the tube a a circular plate of opal glass can be moved from or 
towards the light s ; its distance from s is read in centimetres on 
the scale s by means of an index fastened to the pinion p. At 
right angle to tube a a second tube b is fastened. This tube can 
be rotated in a vertical plane, and its position in reference to the 
horizontal is read on the graduated circle c. A rectangnlar 
prism contained in tube b in its axis of rotation receives light 
irom the opal glass plate in tube a and reflects this light towards- 

(One sixth full size.) 

Fig. 5. 

the eye piece o, so that the right half of the field of vision is 
illuminated by this light, the left half is illuminated by the light 
entering the tube b at g. 

In making measurements, the tube b is pointed towards the 
source of light to be measured. This light has to pass through 
a square box g in which may be inserted one or more opal glass 
plates, in order to diminish the intensity of the light and thus to 
make it comparable with the standard light. The apparatus 
permits the meRSurement of light in the shape of a flame as well 
as the measurement of diffused light. 

Since the measurement of diffused light interests us most at 
present, a short description of the method will not be out of 

1894.] DISCUSSION. d9» 

A white screen, the surface of which is - absolutely without 
lustre, furnished as part of the apparatus, is placed in a con*' 
venient position, either horizontal or vertical, or at any desired 
inclination towards the source of light. 

The photometer having been located at a convenient distance 
from the screen, the tube b is pointed to the center of the screen. 
The distance of the photometer from the screen can be varied 
within very wide limits, the only restrictions being that the field 
of vision receives no other light than that emanating from the 
screen. The necessary precautions for adjustment having been 
observed, the opal glaiss plate in tube a is moved untn both 
halves of the field of vision appear equally illuminated. The 
distance r of this glass plate irom tne standard light at the 

y B_it?i?2I?J11 

Tandard candle ^^^ 


Fig. 6. 

moment of equal illumination is read on the scale on tube a 
in millimetres, and the intensity of illumination on the white 
screen is calculated from the formula. 

The constant K is previously determined as follows : 
A standard candle is placed exactly one metre distant from 
the white screen and the tube b of the photometer is pointed 
towards the screen, so that the center of the screen, which is 
marked by a cross, is seen in the center of the field of vision. 
As indicated in the sketch, the photometer must be so placed 
that the eye looking through the eye piece sees nothing but the 


white Bcreen. The angle of inclination under which the screen 
is observed may be varied within wide limits without influencing 
the result, it should however not exceed 60° from the normal to 
the screen. 

Equal illumination of both halves of the field of vision having 
been obtained by means of adjusting the opal glass plate in tube 
A, the constant c is found by calculation ; 

Since r is read in millimetres and H is made 1 metre or 10000 
millimetres, 10000 instead of 1 must be taken in the formula for 
<;alculating the intensity of illumination in metre candles. 

A second method permits of measurements of diffused light 
without the intervention of the screen, but for further details I 
must refer to the description of the apparatus by Prof. Weber, 
Elekrotechnische Zeitschriftj vol. v. p. 166. 

Since the whole apparatus can easily be taken apart and packed 
in a box about 24 x 8 x 12 inches, it recommends itself extremely 
well for out-of-door work. In this case the benzine lamp mi^ht 
well be replaced by a small incandescent lamp, provided tnis 
lamp is standardized before and after each set of experiments. I 
have found such miniature lamps very convenient, and quite 
sufficiently constant in candle power for several hundred observa- 

The President : — If there is no further discussion, we will 
go on with the next business. I understand that Mr. Wurts 
has notified the Secretary that it would be impossible for him to 
read his paper on "Discriminating Lightning Arresters and Re- 
cent Progress in Means for Protection against Lightning," today. 
Meanwhile, Mr. Hammer has asked the privilege of the floor to 
explain a matter in connection with the consideration of rules 
adopted by the National Electric Light Association for electrical 
construction and operation. 

Mr. W. J. Hammer : — Mr. President and gentlemen — Secretary 
Porter of the National Electric Light Association has sent me for 
distribution some of the copies of the Standard Rules for elec- 
trical construction and opemtion recently adopted at the conven- 
tion at Washington of the National Electric Light A^ssociation, 
and on behalf of that Association and as chairman of the 
Committee on Standard Rules I wish to bring these rules before 
the Amekican Institute of Electrical Engineers, and I make 
the motion that the chair appoint a committee, preferably of five, 
who will examine these rules with a view of recommending their 
endorsement by the Institute. And in connection with this 
motion I would like to ask that this be taken up as a special 
matter on Thursday. 

I wish to say one word in this connection, and that is that 
these rules are the result of a very large amount of work by gen- 
tlemen connected with a number of committees which have had 

1894.] DISCUSSION. 801 

this matter in charge for years past. Some years ago there 
existed an infinite variety of rules issued by the diflferent insu- 
rance companies, boards of trade, electric light companies, experts 
and others, which rules have gradually disappeared or been 
incorporated in a set of rules issued by the Jjational Electric 
Light Association. These rules have been issued with very slight 
modifications by the International Board of Fire Underwriters, 
the National Board of Fire Underwriters, and the Local Board 
of Fire Underwriters without, however, giving any credit to the 
original source, which is the National Electric Light Association. 
Various efforts have been made to have one single set of rules go 
out. It is my hope and that of others that before this year expires 
some action will be taken which will bring about this long sought 
for result, and as these rules that are issued by the National 
Electric Light Association are to all intents and purposes the 
same ones which are issued by the Board of Fire Underwriters, 
with very slight modification, I would recommend that this com- 
mittee be authorized to examine into these rules with a view ta 
recommending their endorsement by the Amerioan Institute of 
Electbical Engineers. This will be a step in the right direc-^ 
tion. There will be undoubtedly certain things open to criticism. 
But these rules are in the hands of a permanent committee 
that are intending to make them the standard rules and keep 
them up to date, and the endorsement of the Institute, as 
a representative body of scientific men interested in matters of 
this character, will assist this good work and I feel sure that with 
this endorsement by the Institute, before the year is out or be-^ 
fore another year come?, there will be but one set of rules which 
will be satisfactory and which will receive the endorsement of 
the National Electric Light Association, the Boards of Fire 
Underwriters, the American Institute of Electtrical Engin- 
eers and all other bodies. It is with this end in view that I 
have asked the privilege of bringing the matter before the 
Institute, and I make the motion that the chair appoint five 
gentlemen to report upon this matter and bring it up before the 
meeting on Thursday. 

[The motion was carried.] 

The President : — The Chair appoints as the committee, Mr. 
Hammer, Mr. C. P. Steinmetz, Mr. A. E. Kennelly, Mr. Edward 
Weston and Mr. N. W. Perry. 

The Secretary made some announcements respecting invita- 
tions and the meeting then adjourned until the following day. 

Tuesday evening the members attended an informal reception 
given by the Engineers and Manufacturers of Philadelphia, 
under the auspices of the " Engineers' Club " and the '• Electrical 
Section of the Franklin Institute," at the Manufacturers' Club. 

A paper presented at the EievetUk Gefured Meet- 
ing 0/ th4 American Institute of RUetrieal En- 
fineers^ Philadelphia^ May i6tk^i994r Presi- 
dent Houston in the Chair. 


BY W. W. GEI80OM. 

It was with great hesitation that I ventured to accept your 
invitation to read this paper before a body of distinguished men, 
who are more or less masters of their own time and have devoted 
it, and dedicated themselves, to science and research, and it was 
finally with a view to enlisting your interest and assistance in the 
fltorage battery problem that I decided to lay before you some of 
the phenomena which have in turn baffled and instructed me, 
occupied my thoughts, and kept my faith from flagging during 
the ordeal through which the storage battery interests have 

The study of a complete curve of discharge of a storage battery 
(Curve III) discloses three rather sharply defined changes in p. d., 
and after allowing for the effect of internal resistance, we find 
that the changes are those of the e. m. f. 

What is the reason for these changes ? Which plate is respon- 
sible for them? 

A microscopic examination of the negative (spongy lead) plate, 
disclosed metallic lead and what appeared to be one, or possibly 
two sulphates. The positive (peroxide) plate, however, showed 
spongiform crystals of very dark color, known as electrolytic 
peroxide; other comparatively large crystals of brilliant red, 
probably Frankland's red sulphate ; others of yellow, probably 
yellow sulphate ; and finally the better known white sulphate of 

The production of these diverse chemical forms must be at- 
tended by production of diverse potentials, and the b. m. f. of the 
battery is possibly a resultant with one or more chemical reac- 
tions predominating at various parts of the charge and discharge. 



That there should be any change of e. m. f. during the charge 
or discharge of the battery, shows the complexity of the chemical 
actions, and as the changes are at times sudden, and at times 
gradual, uniform and invariable, it would seem to point to the 
<5onception that the e. m. f. is the resultant of three or more sets 
of chemical actions. 

The material on tlie charged positive plate of the battery is 



Fig. 1. 

•commonly called peroxide of lead, but it certainly differs from it 
both in its ability to generate electromotive force, and in its ap- 
pearance, and Fitzgerald has pointed out that its composition 
corresponds to the hydrated peroxide of lead, E^Ph^O^, He 
further intimates that a higher oxide of lead may be present, 
such as perplumbic acid, H^Ph^Ori. McLeod has told us how 
peroxide of hydrogen, ozone, and persulphuric acid are pro- 


duced. Then there are the two new sulphates of lead and the 
various compounds of sulphuric acid and water. With this array 
of chemical products to assist our imagination, the wonderful 
curves of b. m. f. of a storage battery on charge and discharge be- 
come comprehensible. And the fact observed by Gladstone and 
Tribe that thirty-four per cent, more of oxygen was absorbed by 
the positive plate than could be accounted for by the production 
of PbO^ becomes explicable. It has probably been used in con- 
verting HiPb^O^ into IliPh^O^. Their suggestion that it was 
absorbed by local action between the grid and the peroxide during 
charge is utterly untenable. There is no such action. And if 
there were, the grid would not last through a dozen charges. 

The conversion of IliPh^O^ into Il^Ph^Oq would account 
for the abnormal rise of e. m. f. at the end of charge, and if it 
be assumed that the E^Ph^O^ is not stable, but yields ozone 
gmdually, thus accoanting for the odor of a freshly charged 
positive plate, it would account for the steady fall of e. m. f. on in- 
terrupting the charging current. The chemist will easily seethe 
relation between these reactions, and the presence of peroxide of 
hydrogen and the continual evolution of oxygen from the posi- 
tive plate, and the fact that a charged cell gradually loses its 
charge, maintaining for days a higher temperature than the air. 

I am sorry that the time allotted me for the preparation of this 
paper did not admit of the preparation of curves showing the 
differences in temperature between certain plates of a cell and 
even between different parts of the same plate. Of course these 
changes, many of them, are very minute, and they are due to at 
least two causes, viz., the liberation or combination of sulphuric 
acid on tlie one hand, and G^ R on the other. 

In order to study the progressive changes on either plates and 
to plot them out in a curve, it is merely necessary to choose fu 
substance which produces a measurable electromotive force with 
the plates, independently of the electromotive force which is 
being produced by the two plates appertaining to the battery, but 
this substance must be one which is neither modified by the 
electrolyte nor by the minute current which it is required to 
produce for the voltmeter. The last is of more consequence 
than is generally understood, as a storage battery which has been 
over-discharged and which has been allowed to recuperate will, 
even if it be of large size, say of 350 ampere hours capacity, pro- 
duce a deflection on a Weston voltmeter (of about 300 ohms),. 







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which at first may be 1 75-100 volts and which will immediately 
begin to fall with a velocity quite appreciable to the eye. Many 
substances have been tried for such a test plate, as for example, 
zinc, carbon, platinum and copper, but nothing seems to be better 
than a well charged Faure or Plante couple of considerable 
dimensions. The use of such plates was first published by Mr. 
Crompton, although they have been used for years in my labor- 
atories, and give concordant results. 

It might be desirable, but it is not necessary to ascertain ac- 
curately the exact fraction of the total e. m. f which is due to 
the plate under test. It is important, however, to know the rate 
of its change of e. m. f. while the cell of which it forms an indi- 
vidual part is discharging or charging. 

Referring to the Curve III entitled Plante Cell, it will be ob- 
served that the negative plate maintains a nearly horizontal line, 
until the p. d. of the couple on discharge has fallen to 1.9 volts, 
while the positive plate maintains a curve almost parallel to that 
of the cell, showing that the characteristic curve on discharge of a 
storage battery with plates of nearly equal capacity is due mainly 
to the reaction in the positive plate. 

At the end of the charge, however, the characteristic curve of 
E. M. F. is due to the negative, the rapid rise of its curve being 
nearly parallel to that of tlie battery, w^hile tlie rise of poten- 
tial of the positive is nearly a straight line, which, however, is 
gradually rising. 

It should be noted that this curve is the time e. m. f. and is 
not dependent on the internal resistance of the cell, which reaches 
the maximum shortly after the 14th hour in this case, and re- 
mains quite constant during the remaining seven hours of the 
charge. But while the e. m. f. is not dependent on the internal 
resistance, the sudden changes in each curve are usually simul- 
taneous, indicating a common cause. 

It may be considered proven, therefore, that in a storage bat- 
tery with plates of nearly equal capacity, the changes in the 
positive plate determine the characteristic curves of potential on 
discharge, and that the changes in the negative plate determine 
the characteristic curves of potential at the end of the charge. 

A curious feature in charge is the intersecting of the curves 
of the positive and negative plate at several points. At the 
beginning of charge (Curve III) the two plates are at nearly the 
same potential, — the positive potential rises rapidly until it reaches 


2.22 volts, when it begins to rise in a straight line strictly pro- 
portional to time. The negative on the other hand rises grad- 
ually until it reaches 2.18 volts, then it rises rapidly, intersecting 
the positive curve in 14^ hours and at 2.24 volts, and continuing 
to rise until it reaches 2.40 volts in Ifif hours, whereafter it re- 
mains constant for the five hours which the positive requires to 
reach the same potential. 

To trace the history of a negative during discharge, {vi/Ie 
Curve I) it fell in five minutes .135 volts, in the next six hours. 
.035 volts, in the following hour .250 volts and in 15 minutes 
more, 1.500 volts, showing less capacity than the positive plate. 
In half an hour after stopping discharge it recovered to 1.9 volts — 
jumping instantly on charge to 2.08 volts, and in 12 hours of 
charge arose only .05 volt. Of course the rate will not modify 
the general characteristics of the curve. 

Within the working limits of charge or discharge, the nega- 
tive did not Vary over 2 per cent, of potential difference. 

The history of the positive in this curve is not so satisfactory. 
Falling rapidly to 2.(»4 in ten minutes it fell thereafter in a 
gradual curve .115 volt during the normal time of discharge, a 
fluctuation of about 6 per cent. Ultimately the positive shows 
more capacity than the negative. 

The total fluctuation of the cell during the six hours after the 
first five minutes was per cent, in discharge down to 1.9 volts. 
This was the fluctuation of the p. d., that is to say it was the 
fluctuation which would be noticeable to the engineer in practi- 
cal service and included all changes due to internal resistance. 

The usual construction of storage batteries — all the plates of 
one name being permanently fastened to one heavy conductor — 
has heretofore interfered with the study of the individual plates 
of a cell. To the end, therefore, of facilitating this investigation, 
the author constructed some cells with independent plates, con- 
necting all those of one name to a common mercury trough, 
either directly or through intermediate resistances as in Figure 1 . 

The resistances were made such, that one ampere would give ten 
divisions on a dead beat galvanometer, and as each division could 
be divided by the eye into tenths, the current passing could be 
read within one-hundredth of an ampere. An independent 
ammeter and an adjustable mercury resistance were inserted and 
the total current kept constant. The cells tested in this way 
were of three types. The pasted cell of the Accumulator com- 




pany, the chloride cell and the Plants cell. The object in testing 
a chloride cell was to ascertain whether the exceedingly good 
contact (produced by casting the grid around the active material 
while the latter was hard, and allowing the molten metal to con- 
tract upon it) would operate to lessen the somewhat remarkable 
variations in the behavior of all storage battery plates, but this 
was not the case. Neither was there any marked difference in 
the behavior of the Plants cell. 

The following characteristic readings were obtained from the 
three types of cells at their normal discharging rates : — 


















































































































































Amperes. Volts. 



6.00 2-035 
5-93 i 2025 
5.90 1 2024 
5.89 1 2.021 
S.Q2 2.025 
5.9» »•« 
5.95 2.oaa 









The curious phenomenon was presented of variations of cur- 
rent amounting to 30 per cent, in plates manufactured rigorously 
alike, kept in parallel and subjected to like treatment during 
their previous life. In cases where the discharge is pushed below 
1.8 volts I have observed even more serious diflFerences amount- 
ing to a variation of about 225 per cent., one reading being 2.8 
amperes, another 6.4 amperes for perfectly good new plates 
carefuDy treated. 

And perhaps a still more curious fact was the differences of k. 
M. F. of the plates in the same cell discharging through equal 
resistances and connected finally in parallel to the same circuit — 
the B. M. F. ranging from 1.60 volts to 1.85 volts for neighboring 
plates in parallel in the same cell, at the same time. On inter- 
rupting the circuit at the end of the discharge of a cell, a consid- 
erable flow of current as might be expected passed from one 
plate into another and it was hours before the batteries reached 
equilibrium after the external circuit was open. 

The discharge of one positive into its neighbor, was a rather 
unexpected result. It bad been thought that if one plate had 
less capacity than its neighbor it would simply stop discharging 
at a certain point, but that its e. m. f. would always be equal to 
that of its neighbors and that therefore, no current would flow. 

The explanation of the phenomenon appears to be that the 
deficient plate keeps on discharging at a lower rate than the per- 
fect plate, and finally reaches a much lower point of discharge. 
On interrupting the current, the plate which has not been dis- 
charged so far, rapidly recovers a higher voltage than its neighbor 
and. therefore, discharges into it. 

This effect must also take place in the different parts of any 
one plate, and may be a cause for the formation of peroxide on 
the surface of a negative plate after a discharge, a phenomenon 


which I have never noticed, but which has been remarked by 
too many observers to be ignored. 

The two outside negatives give more than their proportional 
amount of current on discharge, the current being actually less 
than on the other plates, the potential remains higher, and the 
discharge is therefore a little greater. This, in turn affects the 
positives next to them and these positives are usually the first to 
disintegrate in a carefully used cell. This fact was most notice- 
able in batteries used on the Eckington and Soldiers' Home 
Railway at Washington, where out of 45,000 positive plates, 
there did not occur a single instance of buckling, and yet the 
outside positives always showed 'greater disintegration than the 

The tendency of one part of a plate or one portion of peroxide 
to discharge faster or slower than its neighbor, is one of the 
reasons which induced us to adopt the equi-potential methods of 
connecting up the several plates of the storage battery. It is to 
be noted that these phenomena occur to a serious extent only 
when the batteries are discharged below 1.96 volts of potential 
difference per cell. 

The above tables afford the most complete proof of the irregu- 
larity of the chemical actions which produce the electromotive 
force of the battery. Now one plate is giving current, now 
another. And most remarkable of all, the different sides of the 
same plate exhibit differences of potential at their terminals 
which I can only attribute to differences of internal resistance, 
both in the electrolyte within the plates and in the porous 
.active material itself. 

The active material during charge and discharge is undergoing 
chemical change irregularly, not merely in the different plates, 
but in the different sides of the same plates, and as the active 
material is made up of large numbers of little pellets isolated 
from one another by the grid, the conclusion seems inevitable 
that one side of a given pellet is active to a different degree from 
the other side. It is not necessary to conceive that the e. m. f. 
generated on one side of a pellet is as different from the e. m. f. 
of the other side as would be indicated by the potential differ- 
ence at the plate terminals. The more reasonable conception 
appears to be that the internal resistance of one side of a pellet 
is sometimes greater, sometimes less than that of the other side, 
varying with the unequal chemical action. But I cannot escape 



[May 16, 

the coDclasioQ that there must be some real difierence of poten- 
tial and consequently local action — not merely between the parts 
of the grid, but between opposite sides of the same pellet or 
paste. This would account for the fact observed by Ayrton that 
a working cell is always above the temperature of the air — even 
when its own temperature is falling in discharge. 

In 1890 Prof. Ayrton in his most valuable contributions to 
storage battery literature independently noticed the fall of tem- 
perature in a discharging cell, and published a curve which is 
reproduced in Fig. 2. 



2 1.1 



= 1.( 


I 0.8 



,2 0.; 





Variation of Temperatiffd during DIacharge and Charge 

4k / 
v^ / 

1. 2. 3. 4. 6. e. 7. e 

Timo !n Hours from Beginning of Discharge and Charge 

FiQ. 2. 

The explanation for at least a part of this phenomenon is sim- 
ple. If, as we all know, the addition of sulphuric acid to water 
raises the temperature, it is natural to infer tlmt the removal of 
the acid from the water will lower the temperature. The former 
occurs on charge, the latter on discharge. 

This fall of temperature on discharge was first brought to my 
attention in 1887, when some of the cells of the Julien cars on 
Fourth Avenue, New York City, were reported to heat unduly, 
and the explanation offered was, that they were called on for 
increased currents on certain grades with unfavorable conditions 
of the tracks. As some of the cells did not heat I was not satis- 


fied with the explanation, especially as the resistance of the cells, 
about .002 ohms, would only account for about IJ heat units 
even on 100 amperes discharge which the cells produced at 
moments. I then investigated the question and found that the 
temperature actually fell even with heavy current, when the 
cells were in good order. 

The potential of a cell is partly due to the degree of charge of 
the positive, and partly to that of the negative, and partly to the 
electrolyte. If a negative plate, taken from a fully charged 
cell indicating say 2.65 volts on the normal charging current, is 
coupled with a positive from a partly discharged cell, indicating 
say 1.9 volts on its normal discharge current, the e. m. f. of the 
combination will lie between the two. If the couple be removed 
to a stronger or weaker electrolyte, the e. m. f. will rise or fall 
accordingly. So that a measurement of the p. d. at the terminals 
of the cell is not an infallible indication of its condition of 
charge. If both plates are equally charged, the indication is 
most useful, but when as frequently happens in actual service, 
one plate is further discharged than the other the p. d. is 

The variations of specific gravity of the electrolyte are practi- 
cally proportional to the ampere hours of useful charge or 
discharge — barring local action, short-circuiting, change of tem- 
perature, and a gradual sulphating of discharged positives when 

The variations of the internal resistance of a cell affords 
a valuable indication of the condition of its active material, 
and therefore of its degree of charge. These variations 
have been attributed to the varying porosity of the active 
material — the electrolyte becoming more and more excluded as 
the pores become clogged. But this explanation does not account 
for the odd but invariable nature of the characteristic curves of 
the internal resistance. If this were the true explanation, why 
does the curve fall rapidly in the early part of the discharge 
instead of rising ? Why should it remain constant for the greater 
part of the useful discharge? Why should it suddenly rise to a 
great degree, and then fall in the middle of a prolonged charge ? 
Why is the internal resistance less, instead of more, on a higher 
rate of discharge ? These facts are not easily reconcilable with 
the clogging theory, and our knowledge of the chemical reaction 
is not sufficient as yet to afford a convincing explanation. 


Experience shows that it adds greatly to the life of a cell, and 
brings other advantages to stop the charge at between 2.3 and 
2.45 volts, and to stop the discharge at 1.90 or 1.95 volts, while 
a comparison of the accompanying curves of a cell will show that 
these ix>tentials are reached shortly before, or during a sudden 
rise of the internal resistance. 

A very curious misapprehension prevails among some battery 
people (in spite of the airing the subject has again and again 
received) to the eflFect that the negative plate has more capacity 
than the positive. If a cell be discharged at a high rate to 1.85 
volts for (Bxample, the positive plate will show a much lower 
potential than the negative, and might therefore be deemed to be 
more discharged. If then the negative element be transferred 
to a freshly charged positive element, the negative will usually 
show a considerable additional capacity and this has been cited 
as a proof of the erroneous statement. But if the positive be 
similarly treated, it usually shows considerably greater capacity 
than the negative. This is especially the case with the Faure 
cell in Curve la in which the positive actually has 25 per 
cent, more volume of active material than the negative, and 
shows 45 per cent, more capacity ; and is even so on a Plants 
negative which has as much active material as the positive, and 
\ et the latter has nearly 10 per cent, more capacity. 

The positive plate is usually made of greater capacity than the 
negative in order to prevent it from ever becoming discharged, 
to allow for its gradual loss of active material, but there are 
grounds for doubting the propriety of so doing. A negative 
plate ought never to be discharged so far as to drop after the 
first ten minutes, more than 1 or 2 per cent, in voltage, yet the 
temptation to do so with 45 per cent, excess of capacity in the 
positive is very great — with the result of causing shrinkage of 
the negative paste and a serious loss of capacity in the cell. 

There is another action which goes on in storage batteries and 
presumably in other forms of electrolyte chemistry, which 1 have 
not seen explained, nor in fact described. 

When the chemical reactions in an electrolytic cell are simple, 
as for example, decomposing sulphate of copper or sulphate of 
zinc, the amount of action is proportional to the ampere hours. 
But when the possible chemical reactions are complex as in a 
storage battery, the changes are governed by the potential differ- 
ence as well as by the current, probably because one of the com- 


ponents requires a different electromotive force to break it up 
from that required by another. A curious result ensues. Per- 
haps the current governs the amount of chemical action and the 
potential the kind. Our factory department reports that if a plate 
pasted with red oxide of lead is opposed to a plain lead grid in a 
" forming " bath, the formation of peroxide proceeds evenly and 
uniformly in the well known way. If it be opposed to a pasted 
negative the same result follows. But if it be opposed by 
another positive plate, a different action ensues, and the unformed 
plate cannot be properly converted to peroxide until the other 
positive has been completely reversed, and converted into a 
negative, thus raising the potential difference of the cell. In 
the Curve II it will be noted that at the time the potential 
of the piles suddenly rises, due to the sudden increase of the 
potential of the negative plate, there is at the same time a sudden 
increase of the internal resistance of that plate. This is, how- 
ever, accompanied by a sudden and apparently sympathetic 
perturbation of the internal resistance of the positive plate, show- 
ing that some chemical change occurred in it, quite different 
from the usual action. This perturbation ceased as soon as the 
negative potential ceased to rise. 

The purple color which is frequently observed in the vicinity 
of the peroxide plate has been variously attributed to the presence 
of gold, iron, manganese, etc. But as the phenomenon is observed 
anywhere and everywhere on the face of the globe, now in one 
cell, now in another, it seems more likely to be some unusual 
form of lead. The persulphide of lead is purple, and it may 
even be that the unstable elusive per-plumbic acid — if it really 
exists at all — is the source of the evanescent but beautiful tint. 
A freshly charged plate has a purplish slate color, very different 
from one that has been idle for a long while. 

There are two other phenomena to which I will refer briefly 
in the hope that some members may be able to throw some light 
on their cause, viz : The sudden spontaneous discharge of a fully 
charged positive and the tendency to buckle away from the light, 
i. e, with a concave face toward the light. Wherever the ten- 
dency to buckle is great, as in treating Plant6 plates in some of 
the more rapid methods, I have observed that when a single 
positive is suspended freely a great distance from a negative in 
the center of a large jar, the buckling is invariably away from 
sun light. The plate may be turned around, it may be moved 


quite close to one negative or the other, yet the buckling repeats 
itself invariably from the light. The plate may be straightened 
as you will, it may be left with a slight curve in the other direc- 
tion, yet neither the natural differences of tension in the two 
sides of the plate, nor the increase or diminution of electrolytic 
action on either side has any influence in buckling compared, 
apparently with the action of direct sunlight. 

It will be remembered that Prof. Ayrton in one of his valuable 
contributions to storage battery literature, commented on the 
theory of Mr. Crompton regarding the effect of light on the sul- 
phating of the negative plate, and detailed an interesting experi- 
ment which although not conclusive, tended rather to confute 
this theory. Sir David Salomons remarked upon the effect of 
light on the glass cells causing them, he said, to crack. Alto- 
gether it would seem that storage batteries are devices which 
engineers would do well to keep in the dark. 

The automatic discharge of the positive plate is a compara- 
tively rare phenomenon. In my experience I have secured 
accurate data in only three instances. I am under the impres- 
sion that Sir David Salomons, when by his courtesy I was 
enabled to examine his splendid private plant in 1886, mentioned 
this phenomenon, but 1 do not And it described in his book, and 
as it may not have recurred in his experience he may have felt 
some hesitancy in publishing it. 

On one occasion a cell was reversed experimentally, and the 
reversing charge continued until 470 ampere hours or three 
times the normal capacity of the cell had been passed through it 
The potential attained 2.41 volts on a low charging rate. The 
positive had the healthy dark color of electrolytic peroxide of 
lead and was freely gassing, showing that it was as fully charged 
as possible. The charging current was interrupted and the e. m. 
F. fell gradually to 2.12 volts in a perfectly normal way. In 35 
minutes a curious seething sound attracted my attention to the 
battery, and I found it in a state of violent, almost explosive 
ebullition. The gas given off was pure oxygen in immense 
quantities. The temperature at the bottom of the cell had risen 
from 68° F. to 85° F. and at the top of the cell it reached 109° 
F. Fifteen minutes later the cell was quiescent, the voltage had 
fallen to .24 and the specific gravity from 1.157 to 1.123, — the 
lowest point which it had reached 470 ampere hours before. 
Two or three days later the e. m. f. was zero. 

1894.] GRI800M ON THE 8T0BAOE BATTERY. 316 

During the progress of the phenomenon and afterwards, the 
cell was examined carefully with the most minute care for any 
defect, short-circuit, or other irregularity and it was found to be 
in perfect order. A further charge of 876 ampere hours or 
about six times the normal capacity was given at a normal rate. 
On this charge as well as on the first reversal charge another 
curious effect was observed — the voltage rose in 15 minutes from 
zero to 0.18, in one minute more it jumped to 2.63. It then 
gradually fell to 2.0J in about 7 hours and thereafter gradually 
rose to 2.48. The discharge was normal to 148 ampere hours 
and presented a peculiarity of a fnlly charged cell, that is to say, 
thoE. M. F. fell in two minutes from 2.05 on 30 amperes to 1.935 
and then rose in a few minutes more to 1.94 volts, and then 
gradually fell the usual way. 

Here, then,is the story of a complete automatic discharge of posi- 
tive plates from the beginning of the preceding charge to the end of 
the following normal discharge. Was it because the peroxide formed 
only to a certain depth in a spongy lead and so densely as to 
exclude the electrolytes for a time, so that when the liquid at last 
penetrated the spongy lead a violent local action ensued ? This 
would account for the heat, and for the fall of potential and 
of specific gravity, but would it account for the liberation of 
immense volumes of oxygen? I have frequently noticed the 
presence of considerable quantities of peroxide of hydrogen in 
electrolytes. Gladstone and Tribe have also remarked this sub- 
stance, but intimate that they found it in minute quantities only. 
Jn some cases, however, 1 have observed it in very considerable 
amounts. Is it possible that this substance was present and exer- 
cised its well known property of liberating' one atom of oxygen 
from peroxide of lead,and another atom of its own oxygen at the 
same time? This would account for all the phenomena, but what 
accounts for the peroxide of hydrogen in such an enormous 
amount, and why does it not always discharge oxygen from the 
peroxide ? And finally is it possible that the continuous evolu- 
tion of oxygen on the positive plate while the cell is idle is some- 
times due to the presence of peroxide of hydrogen in minute 
amoimts, and not merely to what has been called local action. 
I trust some of the gentlemen present will enlighten us on this 

Perhaps the most striking peculiarity about the modern storage 
battery is the diversity of opinion among professional electricians, 


as to its utility and commercial value. Men of the highest rank 
as electricians and engineers, are ranged on either side of the 
question. Men of affairs who have put them to a commercial 
test exhibit a like divergence of views. Men who have tried the 
storage battery for a year or two, have written about it in the 
most flattering terms, and have discarded it later. Men who 
have used accumulators ever since their introduction when they 
were much less efficient machines than now, continue to use 
them, and would under no circumstances be induced to part with 
them. Unmitigated praise on the one hand, and unmitigated 
contempt on the other. Broadly stated the European consensus 
of opinion, both technical and commercial, may be said to be in 
favor of storage batteries. The American view until now has 
been mainly the opposite. What is the ground for this wide 
discrepancy ? Why is cautious conservative Europe so far ahead 
in the race ? Why is America a laggard in the running ? 

The answer is not far to seek. Storage batteries are almost 
always an economical success abroad, while here they have been 
too often an economical failure in the past. And the reason is 
that the Europeans always demand a margin for safety, while the 
Americans, with less capital and keener competition, are tempted 
to sail too close to the wind. 

A storage battery continually worked to its commercial rating 
is a commercial failure. A storage battery worked sufficiently 
within its capacity is invariably a commercial success. 

It has been said of Watt that he pursued careful and exhaust- 
ive experiments upon the power of horses for all day work, and 
that he ascertained that the average power which they could 
maintain for ten hours was 22,000 foot pounds per minute, but 
in rating his engine he added 50 per cent, and called the horse 
power 33,000 foot pounds per minute, so as to make his new 
pumping devices more than satisfactory substitutes for horses. 
Would that storage battery people had been equally wise. 

A battery's discharge should be stopped after its e. m. f. has 
fallen to 2 volts or at furthest to 1.9, unless it be desirable to 
draw upon its reserve. It should be understood that a full dis- 
charge, that is, to 1.8 volts is working a battery to the danger 
limit and is unadvisable for the following reasons : 
a. Kegulation is troublesome. 
h. Efficiency is low. 
6'. Dangerous molecular changes take place (as indicated by 


changes of internal resistance and changes of electromotive 
force as well as occasional buckling.) 

d. Uneven plates discharge into one another after the circuit is 


e. The life of the battery is diminished. 

The writer has had occasion to watch with the closest scrutiny 
a considerable number of plants, aggregating perhaps some 
millions of plates. These batteries were rated like all reputable 
makes, well within their capacity in ampere hours measured by 
charging the battery to about 2.65 volts, and then discharging it 
until the potential diflference was 1.8 volts per cell. Some bat- 
teries have been spoiled by bad management and neglect, and 
some by false economy or bad engineering at the very start ; by 
eliminating these, there remain a very large number which were 
successful or were failures for no apparent reason. The utmost 
care was exercised at the factory. The constituent materials 
were analyzed as soon as purchased. Able engineers watched 
the processes of manufacture, but while the quality of the bat- 
tery was improved until no flaw, mechanical, electrical or chem- 
ical seemed to remain, still an occasional failure occcured in 
actual practice and the cause eluded our search. 

Finally by classifying the failures and successes, the truth 
dawned upon us. Wherever the battery was exhausted to its 
full capacity daily, its life did not exceed 500 discharges, but 
wherever it was worked within two-thirds of its capacity, com- 
plaints were unknown. 

Exhaustive tests were undertaken and some curious phenomena 
heretofore unknown to the writer, were disclosed, and after some 
hesitation he concluded that they might be of interest to this 

It is natural to ask why the rating should not be changed so 
that the owner of the battery would not be tempted to work it to 
the danger limit. It ought to be done, but in these days of close 
commercial figuring it would be difficult to sell a battery which 
appeared castef^is parihicSy to cost 50 per cent, more than its com- 
petitors. However, the present rating is strictly accurate and 
has the sanction of custom the world over. It is only necessary 
for the engineer to remember to add 50 per cent, of the capacity 
as a factor of safety to his maximum load, just as he allows 
several hundred per cent, in calculating the strength of a bridge, 
or an axle. 


This additional amount is not a dead loss in investment. It 
produces many countervailing advantages. It saves the neces- 
sity for regulation in most instances. It provides a very effec- 
tive and safe reserve for cases where the charging apparatus 
breaks down and for many other cases, and it improves the 
actual efficiency of the battery which rises from about 80 per 
cent, to nearly 90 per cent, when used with a sufficient reserve. 
And for cases where it is necessary to maintain a constant differ- 
ence of potential, such as electric lighting, it raises the efficiency 
much more, because in these cases the commercial efficiency must 
be rated not from the average point of electromotive force but 
from the lowest point to which the battery falls on discharge 
and when used in this way the p. d. drops only 2^ per cent. All 
the E. M. F. above the lowest point must be wasted in order to 
secure regulation, unless the troublesome method of regulating 
by the introduction of extra cells is adopted. 

In circuits where this regulation is of no consequence as e, g. 
motor circuits for cars, all the b. m. f. is utilized in increasing the 
car miles per unit of energy. 

In this connection it is perhaps worth while to call attention 
to a very common misapprehension on the part of engineers. A 
storage-battery for trolley systems or other central stations for 
the production and utilization of electricity haa heretofore been 
regarded in this country as a very expensive addition to the plant. 
But this is not always the case. There are many opportunities 
for introducing storage-batteries as a part of the original plant 
without increasing the cost, as for example in cases where the 
maximum output is two or three times greater than the average 
output. In the tables here given I have taken Emery's figures 
for a basis for the steam plant. 


Cost of steam plant $70,000 00 

Electric plant, 750 kilowatts, at $30.00 per kilowatt 22,500 00 

$92,500 00 


One-half steam plant $35,000 00 

One-half electric plant (375 kilowatts) 11,250 00 

1,500 kilowatt hours, accumulator capacity, at $30 per kilo- 
watt hour 45,000 00 

$91,250 00 


Now that batteries are made in large units and in much more 
compact shape than formerly, with increased facilities for hand- 
ling, it is to be hoped that the engineers in this country will be- 
gin to give the subject of their introduction more attention, es- 
pecially as a cell having a capacity of twenty-four kilowatt hours 
occupies a floor space (exclusive of connections) of less than a 
square yard. 

The points I have sought more particularly to lay before you 

1. That the chemical reactions in a storage battery cell must 
be complex, in order to account for the curves of e. m. f., tem- 
perature, and internal resistance. 

2. That the current and the e. m. f. of the component plates 
of a cell, and of each part of each plate, are constantly fluctu- 
ating, in spite of the fact that no source of electricity can compare 
with a storage battery for steadiness and constancy. 

3. That by reducing the normal output of a battery by about 
thirty or forty per cent, the discharge can be mainly confined to 
one set of chemical reactions, thus prolonging the life of the 

4. That the negative and positive plates are apt to get out of 
step, therefore the battery should be given an occasional over- 
charge when necessary, but only when necessary to get them in 
line again. 

It may fairly be said that none of these points are new. Only, 
instead of being mere opinions, accepted by one set of experts 
and rejected by others, they seem to me to be logical and inevi- 
table deductions from the phenomena herein disclosed. 

I desire to acknowledge the aid I have received in the study 
of these phenomena from my very competent laboratory assist- 
ants, as well as the accurate and fatiguing work, both night and 
day, kindly undertaken by two of them, Mr. Hugh Lesley aided 
by Mr. Norman Mellor, in making the measurements and plot- 
ting the curves herewith presented for your consideration. 




Dr. Louis Duncan: — In a paper which I had the pleasure of 
reading before the Institute some years ago, I described some 
experiments on some of the points brought out by Mr. Griscom, 
and I would like to say a few words about them. In the first 

Slace, with respect to the local action taking place in the plates, 
Ir. Weigand and myself made some investigation on this point, 
and found that the local action between parts of the same plate 
was very considerable under certain conditions. We found that 
when the cell had been very heavily discharged, that the chemi- 
cal condition of different parts of a plug of active material was 
different, and a local action took place, which tended to make the 
plug uniform in its constitution, and this accounted for a part of 
the increased lofes of energy when the discharge rate in a battery 
was high. Again I see that Mr. Griscom states that Professor 
Ayrton discovered the cooling of a storage cell on its being dis- 
charged. Mr. Griscom could not have read Professor Ayrton's 
paper carefully, or he would have noticed that Professor Ayrton 
nimself attributes this discovery to myself and Mr. Weigand. 
We tried to explain the cooling effect by the taking of sulphuric 
acid from the solution, but this did not account for all of the 
cooling, and there must be some other cause for it. There is a 
considerable amount of energy given to a cell which is never 
given back again, but which results in the formation of com- 
pounds which are not reversed on discharge. 

I see that Mr. Griscom states that the theory held by some 
people that the decrease of the porosity of the plugs changes the 
resistance of the cell, is untenable. In the paper by Mr. Weigand 
and myself to which I have referred, we maae some experiments 
on the porosity of plugs both when completely charged, and 
when discharged, and we found that they were much more po- 
rous when charged. We wanted to hnd why it is that a high 
rate of discharge is injurious to the battery, especially if it has 
been partly discharged, and also why the electromotive force of 
a cell drops faster when the battery is partly discharged than 
when it is fully charged. We found that when the discharge 
rate is rapid, acid is taken from the solution inside of the plug, 
thus, of course weakening the solution, which only gains acid 
again by diffusion from the outside. The diffusion decreases 
greatly as the battery becomes discharged, and when a certain 
strength of current is taken from it, the acid in the plug becomes 
greatly impoverished, and a phenomenon occurs which is men- 
tioned by Gladstone and Tribe in their work on the storage bat- 
tery. They found that when the solution reached a certain 
dilution the chemical action on the lead plates changed, and a 
different compound than peroxide of lead was formed, the plate 
being rapidly corroded. We came to the conclusion then, from 
our work, that a large part of the fall of electromotive force, and 

1894.] DISCUSSION. 321 

the deterioration of batteries at hi^h discharge rates was due to 
the weakening of the acid in the plng, and from our experiments 
on the rate of diffusion in the plug, we saw that botli of these 
effects would be exaggerated as the battery was discharged, and 
the rate of diffusion was lowered. As the chemical action when 
the battery is partly run down takes place on the inside of the 
plug, the resistance will naturally be increased both bv the 
greater distance from the support plate, and the decreased con- 
ductivity of the material through which the current must flow 
to the support. 

There is one thing that seems to be particularly interesting, 
and that is the fact that plates in the same cell, after the dis- 
charge has taken place, will give a current between one another. 
Although the fact that local action takes place in the plate, has 
been observed before, yet I do not know of any experiments 
that have been made on the loss of energy due to currents be- 
tween plates of the same name in the same cell. 

There is another very interesting point in the paper, and that 
is the wonderful phenomenon of automatic discharge described 
by Mr. Griscom. I have never seen it take place, and I am very 
certain I cannot explain it. 

Mr. Grisoom :— 1 would like to correct two misconceptions on 
the part of Dr. Duncan. I did not say that Ayrton whose 
unrivalled researches I have not only read but studied, was the 
first discoverer of the cooling effect of discharge, but that he 
independently discovered it and published the first curve show- 
ing tne history of cooling on discharge. Nor did I mean to con- 
vey the impression that uie clogging action of discharge had no 
effect whatever on the resistance of the cell, but that it was not 
the only influence at work. For the resistance varies in some 
parts of the charge and discharge in exactly the opposite way 
from that which would result from the clogging theory. 

As to the irreversible electrolytic actions remarked by Drs. 
Duncan and W6igand, I can only say that I have heard of such 
actions very often since the Faure discoveries were published, 
but if the word " irreversible " be used in its absolute sense I 
have failed to find them — at least during the proper and legiti- 
mate use of storage batteries. 

I entirely concur with Dr. Duncan regardingthe importance 
of the researches made by himself and Dr. Weigand on the 
varying diffusivity of acid in the paste. Such researches give 

Erecision to our thoughts, and mate us feel that some of our 
ypotheses, at least, are builded upon the rock. 


[Communicated Afi^eb Adjournment by Mb. Townsbnd 


Mr. Griscom's paper is a valuable contribution to the literature 
of the storage battery. In ray opinion it is the best storage bat- 
tery paper ever read before the Institute. In the paper Mr. 
Gnscom offers explanations for a number of plienomena before 
unaccounted for, but he also presents a large number of phe- 
nomena for which he asks explanations from the other members. 
I am afraid that the desired information is not forthcoming. I 
say this because the theory of the storage battery is full of 
anomalies such as the following : 

Take a strip of ordinary sheet lead which has been exposed to 
the air and become somewhat tarnished, cut it in two and place 
the halves in the ordinary battery acid and connect with a low 
reading voltmeter. In the majority of cases there will be a small 
E. M. F. shown, due to the mmute differences in the oxidation 
(tarnish) of the two halves of the same strip. Now by carefully 
scraping the positive piece, the voltmeter may be brought to 
zero, after which a little more scraping will produce a deflection 
in the opposite direction. 

This sensitiveness would seem to indicate that there was an 
exceedingly great propensity to local action in the storage bat- 
tery, and it would also seem that a lead grid filled with peroxide 
would constitute a short-circuited couple with an e. m. f. of two 
volts or thereabouts and that when placed in the acid it would 
completely discharge itself in a short time. 

Tnat is not the case, however, as every one knows. In fact, if 
we take two perfectly clean pieces of lead which give no deflec- 
tion on the voltmeter, and coat one with peroxide, even on one 
side the couple will give a considerable voltage, although it may 
be below two volts. That is to say, there is, apparently at least, 
no E. M. F. between the peroxide and the lead with which it is 
in direct contact, while between the peroxide and the lead with 
which it is connected through the voltmeter there is a very 
decided e. m. f. 

The explanation of tViis appears to be that there is a strong 
tendency of the metallic lead and the peroxide to come to the 
same potential as soon as current begins to flow between them. 
There is probably a momentary current on immersing a peroxide 
grid, but it is probably only momentary, even if the grid remains 
apparently unoxidized. The fact that the voltmeter in the 
experiment just mentioned remains deflected for some time with 
two small strips of lead, would seem to show however, that an 
appreciable quantity of electricity passed before equilibrium is 

I am somewhat surprised at the results obtained by Mr. Gris- 
com, in connection with the discharge of one plate into another 
which was at a low potential. So far as my experience goes, it 

1894.] DISCU88I0N. 323 

is rather contradictory to this. I have frequently seen an at- 
tempt made to divide the charge between two equal sets of cells, 
one of which was fully charged, and the other pretty well dis- 
charged. The result was always unsatisfactory. The tendency 
of the E. M. F. of a discharged cell to rise quickly above two volts 
as soon as recharge begins, would soon reduce the current to a 
trifling amount, so that the charges would not be even approxi- 
mately equalized in any reasonable time. 

The presence of peroxide of hydrogen in some cells but not in 
others, is another of the unexplained phenomena which are so 
frequently met in storage battery work. It may be possible or 
even easy to construct hypotheses to account for such irregulari- 
ties, but what is wanted is demonstration and not speculation. 

[Reply to Mr. Townsend Wolcott's Communication by the 


Is Mr. Wolcott confident that the experiment which he details 

froves the existence of e. m. f. due to diflPerences of oxidation ? 
s it not possible that it is due to occlusion of gases? I have 
found considerable differences of potential between two plates of 
chemically clean platinum, one of which had been exposed to 
the air, after being heated red hot, rather longer than the other. 

If two pieces of platinum about one inch square be chemically 
cleaned, heated red hot and immersed in dilute sulphuric acid, 
they may be brought to the same potential by a little manipula- 
tion. If then one of them be removed again, cleaned, heated red 
hot and allowed to cool for a few minutes and then immersed 
in the electrolyte it will at the moment of immersion show a pow- 
erful deflection equal to over a milli-ampere. If, now, the same 
Elate be taken out of the electrolyte again, cleaned, heated red 
ot and plunged while red hot in the electrolyte a very curious 
phenomenon will be noticed — the first deflection will be negative 
and immediately afterward the current will reverse and the 
platinum will resume its positive polarity. 

It is hardly credible that the potentials are due to oxidations of 
the platinum. I am rather inclined to think that it occludes 
oxygen from the air and possibly it occludes an extremely minute 
portion of hydrogen when immersed red hot in the solution. It 
might, perhaps, be worth while for chemists to remember that 
platinum always absorbs oxygen from the air after being heated 
red hot and really to an appreciable extent — enough in fact to 
produce several milli-ampere seconds per square inch under the 
above circumstances. I nave not ^ven careful examination to 
the behavior of lead under these circumstances, but I must con- 
fess that I have not found so great deflections while using lead 
as I obtained with platinum. 

I do not think that there is as much local action in a storage 
battery as has generally been supposed, if by local action is 


meant an electrolytic effect due to the paste and grid. That 
local action mnst ensue with plain lead, coated with peroxide of 
lead when immersed in sulphuric acid is of course unquestion- 
able, but the amoimt of action is limited to the oxidation of the 
metallic lead surface and that oxidation prevents further action 
to such an extent that positive plates which have been in use for 
eight years are not oxidized to a greater depth than ^fir of an 
inch, provided the lead was of good quality and not full of 
minute holes. My own impression is that the loss of energy in a 
storage battery is due to a different kind of local action, to wit : 
that which is caused by the actual differences of potential of dif- 
ferent parts of the paste and acid. This difference of potential 
mav be due to different densities of acid in the pores of the 
active material, or it may be due to different degrees of oxidation 
of the active material, or it may be due to both factors combined. 

[Communicated After Adjournment by Sir David Solomons, 

OF London.] 

I have been favored with an advance copy of Mr. Griscom's 
interesting paper, in which he does me the nonor of referring to 
me in regard to one or two matters. I will, therefore, connne 
myself to saying a few words on my experience since the time 
alluded to in the paper. 

It is quite true that the glass cells are very apt to crack in the 
sunlight. At first I thougnt this must be due to some chemical 
action upon the glass, but such, it would now appear, is not the 
case, for empty glass cells crack in the same way. Therefore, I 
conclude that the cause must be the unequal expansion of the 

lass, for I was unable to make pots, whicn had been very care- 

uUv annealed, crack in the manner described. 

There can be no doubt that the positive plates in a section 
discharge themselves, if left at rest. There appears to be con- 
clusive evidence upon this point. There are two causes for this: 
First, by the slight leakage which exists in every installation ; 
and, secondly, a leakage in the cell itself apart from any local 
action which may take place, in consequence of the materials 
employed in building up a section, and this circumstance cannot 
be avoided, for all substances conduct in a greater or less degree. 
With due care and by the addition of caustic soda or sulphate of 
soda, I have been able to reduce the slow discharge in a very 
great degree. In all cases, where the battery is likely to be left 
at rest for considerable periods, great attention should be given 
to the materials employed for building up the section. Although 
this seems to be a common-sense proceeding, it is one often neg- 


1894.] DZSCTO/S/OJf. 825 

[Communicated aftbb Adjournment by Mr. Fbedebiok 


While I had just missed the presentation of Mr. Griscom's 
interesting paper, on arriving at the Philadelphia meeting, I 
have since carefully peiused its contents. Besides various 
striking points and suggestions, I note some features therein 
which appear to warrant discussion. First in their order are the 
curves and data giving observations on the p. d of the positive 
and the negative plates, wherein the individual plates of another 
cell, which the author terms "test cell," as distinguished from 
the cell under test, have been used as the basis of measurement. 
Why Mr. Griscom should have adopted two separate standards, 
one for each plate under test, is not convincingly explained, but 
it is apparent, that this selection was not a fortunate one. 
Owing to the inconstancy of the standard cell (test cell) itself, 
as shown by its e. m. f. curve, the p. d. curves obtained for the 
separate plates actually represent the resultant values of two 
unknown and varying factors and not, as they purport, the spe- 
cific potential variations of the plates under test. I^or could the 
latter be definitely deduced by allowing for the deviation, from 
a straight line, of the e. m. f. curve of the "test cell," because 
there is no evidence that the individual plate potentials of the 
latter varied alike. Such being the case, the characteristics 
obtained, necessarily become somewhat problematical. 

In reference to the "continuation" discharge, (Faure cell) to 
which Mr. Griscom attaches special significance, it may be noted 
that the negative curve is decidedly odd, and the context rather 
remarkable lor its omissions. The negative p. d. curve preceding 
the ''continuation " discharge, if the compensation above referred 
to were made, would undoubtedly be nearer the horizontal than 
shown, and would be far from indicating a sudden, abrupt break 
to one volt, within the first five minutes of the continuation, and 
to almost zero in five minutes more; indeed, even taking the 
curve as it is, which represents the sum of the potential losses of 
both the standard and the plate under test, it forms an angle 
with the "continuation" curve which it would be idle to 
anticipate in an uninterrupted continuation of the discharge, and 
still more so in an interrupted one, as was the case, unless some very 
untoward accident or interference befell the plate. We are told 
that for the continuation test, the plates were separated and each 
opposed to freshly charged plates in fresh electrolyte. We are 
not told the specific gravity and temperature of the fresh 
electrolyte, which factors influence to some extent the e. m. f.; 
we are not told why fresh electrolyte has been used instead of 
the old one or one liKe it ; nor are we told the period of rest that 
intervened. However, that their combined effect was consider- 
able, and favorable to the positive plate, is shown by the curve 
for that plate, in view of which the negative continuation curve 


appears utterly incredible. Such a state of the negative, one 
might expect if it had been allowed to discharge, as oy a short- 
circuit, or exposure to air, (followed by a momentary recuperation 
in the electrolyte) daring the intermission. It may also be 
observed, by the way, that the "enlarged" continuation curves 
do not coincide with the smaller ones. 

The charge curve (Faure cell) cannot lay claim to being 
illustrative of normal conditions, owing to the abnormal discharge 
(continuation) immediately preceding the charge, and which, of 
course, must have left its impress upon the plates, producing a 
corresponding influence upon the observations following. The 
electrolyte, too, differa here again, rising above its original 
specific gravity owing to the acid absorbed from the '"fresh" 
electrolyte in which the discharge "continuation" had been 
effected. In fact, this gain in the electrolyte invites a comparison 
with the output of the continuation discharge. It should be 
approximately proportionate thereto, but it is not. Allowing 
equal formation of PbSO^ for positive and negative plates 
per ampere-hour of discharge, the amount of acid absorbed 
corresponds to one half of 11 + 108 ampere-hours (the respective 
extra discharge credited to the positive and negative plates) 
namely, 59.5 ampere-hours. The gain shown by the specific 
gravity curve, however, corresponds to 87 ampere-hours if the 
acid temperature had remained constant, but, as the temperature 
rose during the charge (temperature readings are omitted, only 
a rise of 8° F. for a certain period being quoted), and even if 
this had been all the rise occurring between the beginning of the 
discharge and the end of the charge, the gain in specific gravity 
would be equivalent to over 100 ampere-hours. The assumption 
that this difference between 59.5 and over 100 ampere-hours is 
due to a greater ratio of PhSO^ formation during the accounted- 
for extra discharge is not admissible, and the shape of the 
specific gravity curve of the discharge, as far as it goes, (for the 
extra discharge no specific gravity curve is given) would not in 
the least support it. Nor would it seem reasonable to suppose 
that the " fresh " electrolyte was so excessively strong that the 
portion of it that may have been conveyed by the plates made 
such a difference. So that this reminds again of the queer 
behavior credited to the negative plate on the continuation 
discharge. Altogether the curve tables seem but an imperfect 
basis for the conclusions built thereon in the context. 

In regard to standards for taking the individual plate p. d's., 
it would seem beyond question that the use of a single standard^ 
which is either electro-positive or electro-negative to both plates 
under test, would yield curves that bear a definite relation to 
each other, iiTespective of any possible changes in its own 
potential. It would also facilitate the checking-off of obser- 
vations, in-as-far as the distances between the two (p. d. positive 
and p. D. negative) curves obtained must correspond to the 




independently measnreable values of p. d. of the cell; and 
fiimiliarly with the respective e. m. f. values. Dr. Streintz, of 
Graz, Austria, in his extensive storage battery investigations 
{ZeiUchri^t fuer Elektrotechnik^ Vienna, Vols. IX and XL), 
has used zinc as a standard in observing the potentials of in- 
dividual plates during discharge, and his results indicate that 
under proper conditions that metal is very satisfactory. This 
being the case, it is manifest that it will also lend itself to a 
varietj^ of other lines of observations upon lead accumulators, 
including relative capacity tests of individual plates, — even to 
observations upon a complete reversal and its concomitant 
characteristics, — yet leaving a fair working margin l>etween itself 
and the plates throughout all phases. And what is of no small 
advantage, the zinc standard affords a striking graphical illustra- 
tion of the characteristics observed. 




^P.D. Pos. 






P,D. Nag 

. (Pb) 


/ ^ 





Pig. 3. 

In testing the relative capacity of the plates, it is only necessary 
to discharge the cell in series with a larger cell (or two in an 
extreme case), in order to assist in overcoming the external 
resistance (wires, connections, ammeter, etc.) when nearing zero 
p. D. of the cell, as in the case of an ordinary zero test under a 
constant current, and beyond that point when the weaker plate 
or section, owing to its sluggish action, sets up a counter p. d. 
in the cell. The entire test can be made without removing the 
plates or electrolyte, or in any way interrupting the discharge or 
interfering with the proper conditions of continuation, and, 
consequently, without mutilation of the curves which are to tell 
the tale of tne characteristics sought. 

The accompanying Fig. 3 furnishes an example of the general 
shape of curves obtained by this method to and beyond the point 


of the cell p. d. zero. The upper curve indicates the p. d. 
values of the positive plate {2^ — PbOi) and the lower curve 
those of the negative (Zm, — P}>\ zinc being the zero or base line 
common to both. The two curves approach each other as the 
discharge proceeds, finally cross (as at o,) and deviate, if the dis- 
charge is forced toward reversal. Now, if a practical working 
limit of cell p. d. is prescribed or chosen (which should be well 
inside of the steep curvature of the weaker plate,) let special 
note be taken of the Zm, — PhO^ value a, and tlie Zri — Ph value 
^, on passing that limit, because here really begins the com- 
parison of the relative plate capacities. Then, if the positive and 
negative plates have the same capacity, zero cell p. d. (crossing 
of curves) will occur at a point (e) corresponding to (a + J) : 2, 
whereas, if either plate has an excess of capacity, the intersection 
will occur above or below that point; in tne example given, the 
cell zero p. d occurs at o. Thence the discharge is forced along 
until the p. o. of the stronger plate reaches the value {a + h) : 2, 
indicated by the letter h. The diffei^ence hetwe^ the relative 
capa^ties w expressed hy the linear dimension E- — H. Upon 
reducing the capacity of the stronger plate accordingly, the new 
curve would more or less alter its shape at the assumed cell p. d. 
limit, and the latter for the same value would come somewhat 
further inside, as suggested by the dotted lines. The curves (for 
charge, discharge and complete reversal) obtained by this 
method will prove instructive in various ways, and their diflPer- 
ences may suggest further investigation into structural and other 

The drop in temperature of a discharging cell, alluded to by 
Mr, Griscom, is a result dependent upon very low internal 
resistance and moderate current. Under opposite conditions 
the opposite result, namely, a rise in temperature, will occur. 
Mr. Griscom's explanation of the cooling effect may help to 
explain the heating effect also. There are two opposing functions 
in discharging a storage battery, which do not bear a fixed 
relation to each other; the chemical (or cooling) effect being ^r<?- 
portional to the current (as is also the absorption of sulphuric 
acid, referred to by Mr. Griscom), whereas the heating effect 
varies na (P P, Thus, while the cooling effect may predominate 
under favorable conditions, upon increasing (7, a point will be 
reached where the two factors balance and beyond which heat 
will ensue. This balance point, of course varies with different 
types and sizes of storage batteries. In Prof. Ayrton's tem- 
perature tests, alluded to by Mr. Griscom, the cell temperature, 
though remaining above that of the surrounding air, fell slightly 
below that of an idle cell, wherein the heating was due to some 
local action (possibly the same two functions, with their relative 
magnitude reversed. Dr. Duncan and Mr. Weigand^ mention 

1. Transactions vol. vi., p. 217. 

18941 DISCUSSION, 829 

having observed a temperature reduction in some cases, and a 
rise in a number of others, the data on which indicate favorable 
conditions in the latter direction. My own observations were 
also of both kinds, and numerous; especially have I noted a 
marked rise when discharging at such an excessive rate as to 
produce lively gassing at the plates, which was accompanied by 
a marked increase in the internal resistance. Again, in cases 
where a number of cells were confined within a close space 
affording little or no ventilation, (as in an electric launch, etc.,) 
even a slight initial rise would have a cumulative eflPect, to a 
noticeable extent. These observations were made on cells in 
good condition. 

On page 312 the author refers to "a very curious misapprehen- 
sion" prevailing "among some battery people" to the effect that 
the negative plate exceeded the capacity of the positive, and 
then proceeds to prove the contrary by reference U) tests, the 
shortcomings of which have been pointed out above. As a mat- 
ter of fact both conclusions are unwarrantably broad. In view 
of the diverse types that are on the market, it must be observed 
that the relative capacity of the plates is as the manufacturer 
chooses to make it. It depends upon structural features, upon 
the relative size and thickness of tne plates, the relative propor- 
tion of " active material " contained therein and the quality, con- 
dition and distribution of the latter, each of which factors, if 
varied itself, will produce different results. In some accumula- 
tors the positive and negative plates are made exactly alike up 
to the point of final " formation." and in most of these, when 
in good working order, the negative plates have a considerable 
excess in capacity, owing, no doubt, to the spongy lead being 
capable of more thoroughly undergoing the chemical change 
than the peroxide. Dr." Frankland (Koyal Societv, 1890) re- 
marked that " only half as much material seems to be necessary 
for the negatives as for the positive plates." Messrs. Gladstone 
and Tribe made similar observations. Prof. Ayrton^ suggests 
an explanation why in the E.« P. S. (pasted grid) type "it is neces- 
sary to employ nearly twice as mucli lead peroxide as is actually 
needed for the chemical action." Some manufacturers have as 
much as ten years ago recognized the difference and accordingly 
made the positive plates thicker than the negatives, and, although 
Mr. Griscom doubts the propriety of so doing, his company also 
follows that practice. 1 have myself made careful tests of the 
comparative capacities of plates and materials, extending over 
some years, and found a considerable difference in the oxides of 
different makers, their capacities ranging (with grid plates i inch 
thick), under like conditions, from 1.4 to 2.5 ampere-hours per 
ounce of red lead in positive plates, and (with similar grids) from 
2.76 to 3.25 ampere-hours per ounce of litharge contained in 

1. InH. Blee. Eng„ London, 1890. 

330 0RI8C0M ON THE 8T0BAGE BA TTERY. [Blay 16, 

negative plates, in all these cases putting double their amount of 
active material opposite them, to ensure maximmn ontpnt of the 
samples with the usual working p. d. limit, at a nuiform current. 
Among a variety of tests to determine the relative capacity of 
plates working together, I have made a series of experiments 
calculated to vield the most direct results for practical purposes, 
as follows : 1 prepared 3 cells, each containing 4 negatives and 
3 positives ; size 7f x 9 J inches ; thickness, all positives \ inch ; 
negatives, in one cell J inch, second cell ^ inch, third cell ^ 
inch ; ^ inch grids being planed down to the respective thick- 
nesses for the second and third cell. The oxides used were of 
the best quality available (the litharge being specially manu- 
factured for storage battery purposes.) The cells were worked 
daily for several weeks, under normal conditions, and the net 
results, briefly stated, were, that the cell in which the negatives 
were reduced to one half their thickness and the amount of lith- 
arge therein to 38 per cent, of that contained in the \ inch nega^ 
tives, yielded an output only 16 per cent, less than cell 1. (The 
reason for only 38 per cent, and not 50 per cent, of litharge 
being in the \ inch plates was in the perforations being tapered.) 
The object of this experiment was to And how thin a negative 
would airswer for a given positive with the materials used, 
without undue sacrifice in the capacity of the cell, and the re- 
sults obtained approximately correspond with theoretical deduc- 
tions. Generally speaking, the results do not vary exactly with 
thickness, volume and weight, but many other minor points, as 
above indicated, necessarily contribute in determining them ; the 
subject is too intricate to be broadly covered by either Mr. 
Griscom's implied conclusions or the one he undertook to refute- 
I concur with Mr. Griscom in his views on the success of 
storage batteries in Europe, and their lack of success in this 
country. Other points of comparison suggest themselves, 
among which are the generally greater day load of central sta- 
tions in this country, due largely to a more general use of motors^ 
which tends to make the use of storage batteries a somewhat 
less pressing object, and further, the entire absence, until re- 
cently, of large, substantial and durable types of cells suited for 
central station purposes. While in Europe central station types 
have been given tne utmost attention by manufacturers, with 
corresponding success, American storage battery manufacturers; 
on the other hand, have largely endeavored to cope with that 
alluring subject: storage battery traction — unfortunately with 
but little success— and neglected to cater to the central station" 
tield witli types especially adapted to that class of work. 

[Reply to Mr. Fbkderick Reckenzatjn, by the Author.] 

Some of the points made by Mr. Reckenzaun show that my 
paper requires a little further elucidation : — 

First. Mr. Reckenzaun says that the text is rather remarkable 
for its omissions with respect to the curves. I did not pretend 

1894] DIBCUB8I0N. 881 

to give a complete analysis of the curves, which, by the way, 
are perfe-^itly normal, but only to use some features of them to 
illustrate my paper. 

Second. He states that I adopted two separate standards, 
one for each plate under test, and states that owing to the incon- 
stancy of the standard cell, (test cell ), the p. d. curves for the 
separate plates actually represent the resultant values of two 
unknown and varying factors. 

Now this appears to me to show a little tendency — 

" ♦ * * * to divide 

** A hair 'twixt north and north-west side." 

The total discharge of the ''test cell" during the 300 or 400 
readings represented by the curve did not exceed t^-A^ part of 
its capacity. Therefore, there was no change appreciable to my 
instruments in the e m. f. due to the amount of discharge. 
Similarly, the current was about ^J^ of the ordinary discharge 
rate of the plate, consequently there was no appreciable 
modification in the readings due to the discharge rate. The 
total variation of the "test cell '' in discharge is, as shown by the 
curve, about -^ of the total variation of the cell under test, say 
.03 volt, of which about .01 volt was due to the negative and .02 
volt to the positive. And this variation, which Mr. Beckenzaun 
is pleased to call '' inconstancy," is due entirely to the specific 
gravity and temperature of the electrolyte. The advantage of 
using this plan is evident. Inasmuch as the temperature and 
density of the electrolyte affect the *'test cell" and the cell under 
test equally, and inasmuch as the "test cell" and the cell under 
test are of the same nature, this plan enables us to eliminate the 
effect of the change of temperature and of average density from 
those curious changes going on in the plates which it was my 
endeavor to lay before the Institute. 

Third. Later on in Mr. Reckenzaun's communication he 
appears to recommend the use of a single standard and refers to 
the investigations of Dr. Streintz, of Gratz, Austria, who used 
zinc. I have also used zinc in past years, but abandoned it on 
account of its solubility in the electrolyte, its tendency to deposit 
during charge on the negative plate and the false effects due 
thereto and for other reasons. It is true that by using separate 
cells and by taking precautions to prevent the intermingling of 
the electrolytes, it is not impossible to obtain important results 
with the use of a single standard, but unfortunately it is necessary 
to make an exhaustive and complete research into the various 
behaviors of the single standard in the presence of a varying 
electrolyte and a varying storaffe-batterv plate, before it is possible 
to be sure that curves witH any single standard represent 
anything but the misleading resultants of unknown and varying 

On the other hand, by using for the test cell, well-charged 
storage-battery plates, which have been allowed to stand until 


they have reached a stationary e. m. f. you obtain fixed and 
invariable and scientific resnlta because you obtain the loss of 

fotential which is due purely and simply to the plate under test, 
t is as though you measured the difference of potential due to 
the changes in that one plate while the opposing plate had 
undergone no change from the beginning. 

The use of single standards will not do this. They give 
simply a comparison which is not only uncertain in its nature, 
as explained above, but which has no relation to the real use of 
storage batteries. 

Fourth. It does not appear whether Mr. Eeckenzaun or Dr. 
Streintz is responsible for the method which he advises for 
testing the relative capacities of the plates of^a storage-battery. 
The idea of forcing a current for this purpose through a battery 
which has ceased to be active whether through the exhaustion of 
one or both of the plates, is, to say the least, open to criticism. 
If the negative plate, for instance, becomes exhausted first, as 
usually happens, forcing a charge through it means charging it in 
the reverse direction so that you have the anomaly of a negative 
plate charged, or still worse, partially charged as a positive 
opposed to a positive in the same cell. The experiment, of 
course, is interesting ; in fact, I have no doubt that this very 
thing frequently occurred in former practice, in the dark ages of 
storage-batteries, when cells frequently got exhausted hj short- 
circuits and buckling, were straightened and cleaned again, and 
put in service only half charged. Buckling and short-circuiting 
are happily things of the past, but Mr. Keckenzaun's methoa 
would yield an interesting study of the behavior of a battery 
when treated in the best manner to ensure its destruction. 

Fifth. Mr. Keckenzaun says in reference to the continuation 
of the discharge of a Faure cell, that, ''if the compensation above 
referred to were made," the curve would undoubtedly be nearer 
the horizontal than shown. I think there is no reason for this 
conclusion of Mr. Eeckenzaun. The continuation of the dis- 
charge was made with fresh plates of the L type, the capacity 
of vniich was many times in excess of the remaining capacity of 
the cells under tests, — so much so, in fact, that Uiere was no 
appreciable falling off in potential on the part of the larger plates, 
and the curve of the test cell was therefore omitted as 

Sixth. The fall of temperature on discharge is a diflScult thing 
to explain. Unfortunately for Mr. Reckenzaun's explanation, 
the cell will sometimes indicate a rise of temperature and some- 
times a fall under what appear to be, externally, at least, exactly 
the same conditions. I am not inclined to believe that such an 
eminent scientist as Professor Ayrton could have made an error 
due to local action in an idle cell, as Mr. Keckenzaun insinuates. 
And in this connection, as against his theory that there is a 
marked rise of temperature whenever there is ^' a marked in- 

1894.] DISCUSSION, 888: 

crease in the internal resistance," I will remind him of the tests 
which were made under his supervision in our Newark labora- 
tory in 1S87. In one of these tests, the cell was discharged at 
the rate of 40 amperes to 1.8 volts. The records show that the 
temperature of the cell fell .9° F., and at the time when the cell 
reached 1.8 volts, its temperature was actually .4° below that of 
the air, and yet, as everyone knows, the internal resistance of 
the cell under those circumstances was at least double its average 
internal resistance, and the current remained constant at 40 
amperes. This seems to be in direct contradiction of Mr. 
Reckenzaun's theory. 

To be sure, such a test, crudely made in a factory laboratory, 
has not the weight of a test made by Professor Ayrton, assisted 
by competent electricians and checked by all the skill and 
resources of a trained scientist for the express purpose of in- 
structing the scientific world. But when tne test conforms to 
Professor Ayrton's results, it seems entitled to at least as much 
weight as some other crude tests which differ from these results. 

In Professor Ayrton's e«periment he found that the heat pro- 
duced by (7* R amounted to 3,456 calories, whereas the heat loss 
due to the cell cooling down amounted in some cases to 12,000* 
calories — ^three or four times as much. Furthermore, the heat- 
ing due to C^ li in a given cell does not vary directly as the 
square of the current, because, the internal resistance diminishes 
as the current increases, and what is still more curious, the e. m. f. 
itself appears to increase. 

Mr. Keckenzaun talks of experiments in which an excessive 
discharge rate increases the i. b. He must have been using 
cells of extremelv faulty design, or else he must have niade his. 
measurements after the cell had exceeded its proper working 
capacity for the discharge rate, or else he based his statement on 
guesswork instead of experiment. I have never known of such 
a case. 

Seventh. Mr. Reckenzaun devotes some space to what he 
calls the ''queer behavior" of the negative plate in the continua- 
tion of the discharge of the Faure curve and proves that it is 
'^ queer" by an argument based upon certain apparent behaviors 
of the electrolytes as shown by the curves. The facts are not as 
Mr. Reckenzaun assumes. The relative proportions of electro- 
lyte were not the same in the charge and discharge, and there is 
consequently no relation between the actual measurements of the 
specihc gravities in charge and discharge. The specific gravity 
curves are absolutely independent of one another, and if used 
for purposes outside of my paper should be studied indepen- 

The "queer behavior" which so impressed him, is what always 
takes place in the complete discharge of a negative plate of good 
construction and the fact that some electricians did not know of 
this "queer behavior" was perhaps a sufl5cient reason for me to- 


mention it. The fact is only '^ atterlj incredible '' to those who 
are too credulous of outworn theories, and who will not venture 
to subject them to actual test. 

His explanations, that there might have been short-circuits, or 
unsuitable electrolyte, or undue exposure of the ne^tive to air, 
display a sin^lar idea of scientific tests. It may be proper to 
inform him that such infinite precautions hed^e about laboratory 
work of this nature that none of tliese things could occur. 
Moreover, the negative, even if exposed to air, does not lose any 
capacity whatever until it begins to heat ; and after it has heated, 
it does not recuperate to two volts, or more, but behaves like an 
entirely different material with a much lower electromotive 
force. I think all the voltage readings are correct within two- 
tenths of one per cent.; any possible errors in any of the curves 
are in one direction, so that what I particularly desired to set 
forth, to wit, the relation between the curves, is accurately shown. 

Eighth. Mr. Reckenzaun takes it very hard that I should have 
said that a very curious misapprehension prevailed among some 
battery people to the effect that the Begative plate exceeded the 
capacity of the positive, and he then points out alleged short- 
comings of the curve upon which he appears to think I based my 
statement. Of course, I did not rely on any one experiment, 
but upon many hundreds of tests. If Mr. Reckenzaun wants to 
attack them by repeating the tests under the same conditions, I 
shall, of course, have no objection ; but I must protest against 
having my curves demolished by faulty dialectics based on errors 
of fact. 

1 am surprised that Mr. Reckenzaun should not have known 
that the negative plate in all usual and commercial storage- 
batteries of good design has less capacity than the positive, and 
that the curve at the end of discharge for both plates is for a 
considerable space a nearly vertical line, — the loss of a volt in five 
or ten minutes being of usual occurrence. His method of testing 
the relative capacities of the plates is roundabout and the results 
have evidently misled him. The simplest ways are the best. 
My usual method is to place one plate between two others of 
several times its capacity and discharge it to exhaustion. In this 
way its curve is purely its own curve, practically unaffected by 
anything but the electrolyte, and the insignificant loss of potential 
of the larger plates. Care is taken to maintain the electrolyte 
at the proper density. A similar curve is made of the other 
plate and any changes of proportions which may be desirable 
are calculated from tne curves. 

Ninth. The citation which Mr. Reckenzaun attributes to Dr. 
Frankland in support of what appears to be his theory, to wit: 
"only half as much material seems to be necessary for the 
negative as for the positive plate," was made by an anonymous 
writer in the Electrical Beview, of London, of August 22d, 
1890, in an article referring to Dr. Frankland and not by Dr. 

18»4.] DI8CU88I0N. 836 

Frankland himself. It would not be astonishing, however, if 
Dr. Frankland had assumed this to be true, as did many other 
scientific gentlemen at that time ; but experiments of Crompton, 
Anthony Reckenzaun, Drake and Gorham, which I have con- 
firmed myself, show that it is not true. The original idea 
obtained currency, I believe, because in the original formation of 
a battery it took twice as much energy to form a given weight 
of negative element as it did of positive element, and it was then 
supposed that on discharge after formation, the chemical processes 
were reversed ; but such is not the fact. 

Tenth. His reference to the Journal of the Institution of 
JElectrical Engineers^ 1890-1891, containing Professor Ayrton's 
papers, is fortunate, for it contains a refutation of the* very 
theories which he is endeavoring to support by it. In the discus- 
sion following one of Professor Ayrton's papers, Mr. Reckenzaun's 
brother gave a clear and logical explanation of the causes which 
made it difiicult, if not impossible, to furnish a durable negative 
plate with more capacity than the positive, and told why the posi- 
tive plate in the E. P. S. form of battery alwajs showed after the 
■cell was discharged, the presence of a large amount of lead per- 
oxide. The reason he gives for the latter effect is that the nega- 
tive plates become exhausted too soon, in other words had too 
little capacity, and so left the positive plates only partially ex- 
hausted and consequently with a large excess of peroxide. This 
explanation, 1 thiuK, is at least partially true, inasmuch as the 
negative plate in the principal batteries of the world, when new 
And in good condition always becomes exhausted first. 

I ought, perhaps, to add that I referred to commercial batteries 
of usual types and in good condition, and not to the abnormal 
types which occasionally make their appearance in the market 
with excessively large pellets of active material, the centers of 
which gradually grow inactive. 

In this connection, I am sorry that Mr. Reckenzaun was not 
more specific in alleging an error in the " enlarged " continuation 
-curves. I fail to find it. Both curves were made directly from 
the notes of the tests. 

Eleventli. The experiments which Mr. Reckenzaun performed 
for us and which he relates in his paper, viz : the ones where he 
reduced the thickness of the negative plates and obtained 84 
per cent, output with 38 per cent, of negative active material, 
are also explained by Mr. Reckenzaun's brother in the discussion 
before the Institution of Electrical Engineers three or four years 
ago ; in a word, a greater proportion of the spongy lead was 
active in the thin plate than in the thick plate. 

Twelfth. Mr. Reckenzaun's curve, which he says has the 
^' general shape of curves obtained by " his " method," reached 
me after writing the above. I am at a loss to tell from his 
-cautious language, whether the curve was purely hypothetical, or 
whether it was the result of the actual measurements of a round- 


about method. In either case, it suits his argument in appearance^ 
and is an admirable proof of the danger ot using any but direct 
methods of ascertaining scientific facts. There is only one safe 
way of ascertaining the relative capacities of positive and nega- 
tive plates and that is by measuring them independently. Any 
otlier way until checked by a direct method may involve mis- 
leadingand unknown factors. 

Mr. Keckenzaun's curve, (with zinc standard), shows an easy 
slope for one-fiftli of the total discharge to zero on the part of 
the negative, and for one-third on the part of the positive. Such 
a thing never occurred in a normal storage battery discharge. 
During the latter part of complete discharge, the e. m. f. of each 
plate is always on a mad rush to perdition — measured not in 
hours, but minutes or seconds. His curve is not representative 
of the behavior of a well designed cell in normal discharge, nor 
even of the worst commercial cell which has ever come under my 
notice. Nevertheless, the curve is of a novel nature, and if not 
purely hypothetical may open the field in curious and unexplored 

I do not recall at present any other point of importance in my 
paper which Mr. Reckenzaun has attacked. I would like to add, 
however, that such frank, direct and pointed criticism as he has 
made, is always useful as tending to give precision to our ideas. 
Eventually, of course, the truth on whichever side it may be, 
will prevail. 

/a/tfr prnenttd 4/ ih€ RUvtntk Cftural 
MttHng o/tfu American ItuiituU o/Eltciri- 
eal Enginters^ PhileuUlphia^ May lUk^tSi^y 
PrttidnU Houston in the Chair and tU Ch:cog9* 
Mayaads t8g4^ Afr. BionJ. Arnold in tho Chair. 



Pabt I. — An Expkrihbkt with Ltghtkinq Abbbstrbs on a 
8,000- Volt Altbbnatinq Cubbbnt Cibouit, 

Lightning storms in the West, particularly among the moun- 
tains where water power abounds, have up to the present time 
proved a serious drawback to the successful operation of electric 
light and power plants. In some instances these plants are, by 
reason of frequent and violent electric storms, practically in- 
operative during the afternoons of the summer months, and now 
that such far reaching progress has been made in the construction 
of high potential alternating current power transmission appa- 
ratus, the subject of protection against lightning has become of 
vital importance. The ordinary devices which provide auto- 
matic circuit interrupting attachments, and which are still used 
with doubtful success on circuits of low potentials, had signally 
failed to do the work required of them on these high potential 
circuits, and it had become evident that something radically new 
was needed. During the winter of 1892 and 1893 I made a 
searching investigation of this subject, experimenting with dis- 
ruptive discharges and various kinds and combinations of appa- 
ratus which might promise advantageous results, and since that 
time have spent nearly six months in the State of Colorado^a 
land of thunder storms — testing the various forms of apparatus 
which I had designed as a possible protection against lightnings 



and have also made a careful study of such phenomena as pre* 
sented themselves. This work was carried out with the deter- 
mination^'to construct, if possible, some form or combination of 
apparatus which should practically shut out lightning discharges 
from^he vital parts of a system, and thus greatly enhance the 
possibilities of electric power transmission. 
,^The general requirements of efficient lightning arrester appa- 
ratus are : First. To provide discharge circuits which shall ope- 
rate automatically and repeatedly, and which shall with certainty 
avoid j^ dynamo short-circuits or interruption of the system; 

Fig. 1. 
Second. To provide discharge circuits, or so install them that 
they^shall invariably offer a certain path to ground for disrup- 
tive discharges in preference to any other part of the system. 
It follows also from this last, and as a matter of practical experi- 
ence, that ground discharge circuits should be short and straight, 
and that ground connections should be of the most approved 

The difficulties in the way of meeting the above requirements 
on circuits of high potential seemed at first somewhat serious, in 
view of the fact that many of the arresters already used, had 




not only been instantly destroyed by the short-circniting which 
follows each discharge, but, in many instances, the arresters had 
been entirely ignored by the lightning, the discharges preferring 
an armature or converter to the spark gaps of the arresters. The 
correct method for overcoming this latter diflSculty is to equip 
the system with a liberal distribution of liue arresters, which, by 
thus affording frequent opportunities for discharge along the 
line, will greatly lessen the probabilities, or rather necessity, for 

3000 VOLTS 




.a— -a. 

■ l^ ' ' 57 

] [ 



^ ' ^ ' 



Fio. 2. 

discharging in the station. But the country over which most of 
these power transmission circuits are run is of such a dry, barren 
and rocky character as to make it practically impossible to secure 
proper ground connections along the line. Fortunately, how- 
ever, parts requiring protection in these power transmission 
plants are confined to the ends of the circuits, so that it became 
possible to adopt the following general plan, namely : to provide, 
first, an abundant discharging capacity from the line immedi- 
ately before entering the station or power-houses; and second, 



[Maj 16» 

to interpoee between this point and the parts to be protected, 
8ueh a resistance to disruptive discharges as should make it a 
matter of necessity rather than of choice, for these discharges to 
pass to earth over the discharge circuits provided for them. 

The only apparatus which seemed at all available for this work 
was the non-arcing metal lightning arrester, and some efficient 
form of choke coil which might be connected in the circuit be- 
tween the arresters and the apparatus to be protected. As i^ 
well known, the 1,000-volt non-arcing metal lightning arrester, 



Fio. 8. 


which is now almost universally used on alternating current cir- 
cuits (see Fig. 1), consists essentially of seven non-arcing metal 
cylinders arranged side by side with 1-64 inch spark gaps inter- 
vening. The two outside cylinders are connected to the respec- 
tive sides of the circuit and the middle cylinder to the ground, 
thus forming a double pole arrester. For higher voltages, how- 
ever, the number of cylinders must be increased in order to 
prevent the dynamo current from following in the path of dis- 
ruptive discharges. Experiments were, therefore, made to de- 




termine the number of non-arcing metal cylinders and spark 
gaps which wonld be necessary to interrupt a short-circuit on a 
8,000-volt alternator with the potential raised to 3,300 volts. 
Nineteen cylinders, or 18 gaps, were found to offer ample mar- 
gin, and the breaking down e. m. f. on half this number of gaps, 
which would intervene between line and ground, was found to 
be about 70 per cent, of the b. m. f. required to break down in- 
sulation ordinarily used in a 3,000- volt generator. Three 1,000- 
volt non-arcing metal arresters were, therefore, selected as offer- 
ing a convenient means of installing this apparatus (see Fig. 2). 
It is also well known that coils, and even sharp turns in a wire 
offer a high inductive resistance to disruptive discharges. Vari- 
ous forms of choke coils were, therefore, constructed and tested 
with the idea of determining those proportions which, for pre- 
sent requirements, should offer maximum impedance with a given 


Fig. 4. 

length of wire. These experiments will be more particularly 
described in Part II. The form finally adopted was that of a 
flat coil about 18 inches in diameter, and wound with lY turns of 
wire ; the size of the wire varied, of course with the carrying 
capacity of the particular circuit into which it was to be con- 
nected. After further experimenting with various combina- 
tions of spark gaps and choke coils, it was decided that the trial 
apparatus should consist of eight choke coils and twelve 1,000- 
volt non-arcing metal arresters for each end of each circuit; that 
is, four choke coils should be connected in series in each leg of 
each circuit, with discharge circuits intervening. The relative 
positions of these parts are clearly indicated in Fig. 3, which 
represents one end of each of three circuits. 

The theory upon which the selection of this apparatus was 
based will be more generally discussed in Part II.; suffice it to 



[Maj 16. 

say here, that disruptive discharges form nodal points in the 
system, that is, points where there will be a minimum tendency 
to discharge ; hence, to avoid these with any degree of certainty 
a multiplicity of arresters, preferably line arresters, should be 
used. Choke coils form points of reflection, or points where 
there will be a maximum tendency to discharge — hence a dis- 
charge spark gap connected directly in front of a choke coil is 
more likely to receive discharges, than if placed at some other 
point in the system. Properly constructed choke coils also offer 
a very high resistance to the passage of disruptive discharges — 
so that if one or more such coils be connected between a dis- 
charge circuit and the apparatus to be protected, and if the 
discharge circuit or ground wire be short and straight — the pro- 
babilities of safe discharge to earth will be vastly increased. 
Further, disruptive discharges are liable to divide and follow 


t ' -I -t r t- ! I 

4--,- -I- t ;- -, ^ -1-4- i 






2 3 4-6 



Fig. 5. 

several paths, being governed by a complexity of ever varying 
circumstances. For this reason it was decided to connect several 
choke coils in series, so that should only a portion of a discharge 
pass across the first arrester, the balance passing through the first 
coil, a second opportunity for discharge would be found at the 
second arrester, which was also connected in front of a coil, and, 
therefore, at a point of reflection. Should this remaining por- 
tion of the discharge again divide, a further opportunity for dis- 
charge would be afforded at the third arrester, and so on, so that 
by the time the fourth coil was reached, it was presumed that the 
discharge would have spent itself. 

Some of the many experiments made to substantiate this 
theory are exceedingly interesting as well as instructive. Refer- 
ring to Fig. 4, A are the terminals of a powerful influence ma- 




chine, b is a battery of Leyden jars, o a wire which may 
represent the ground, and is connected to the outside coating of 
the jars, l is a second wire which may represent one leg of an 
electric circuit ; a^by o and d are choke coils connected into the 
line L, and in series with each other ; 2, 3, 4, and 5 are inter- 
vening discharge circuits containing spark gaps; 1 is a ^ 
inch spark gap separating line l from the inside coating of bat- 
tery B. If now the battery becomes charged from the influence 
machine a, a large and violent disruptive discharge will take 
place across gap 1 and suddenly charge line l. This discharge 
will then pass to earth g through one oi- more of the spark gaps 

Pig. 6. 

2, 3, 4, 6, according to circumstances. It will be noted now, that 
this arrangement of choke coils and discharge circuits is similar 
to that shown in Fig. 3. The spark gaps were made of rounded 
half-inch brass rod adjustable with a 1-32-inch screw thread. 
The coils were wound with No. 0000 wire, were 3 inches in 
diameter, 6 inches long and contained 11 turns each. 

The following table indicates the very interesting results ob- 
tained by varying the lengths of spark gaps 2, 3, 4 and 5. The 
signs " — ", '•*" and "o" indicate, respectively, a heavy dis- 
charge, a feeble thread-like discharge and no discharge. 


The Spark Gap Numbers 1 

The Spark Gap Lengths 12 

Besolts, Ist — 

2nd — 

The Spark Gap Lengths 12 

Resolte — 

The Spark Gap Lengths 12 

Results — 

The Spark Gap Lengths 12 

Results — 

The Spark Gap Lengths 12 

Results . . — 

The Spark Gap Lengths 12 

Results — 

The Spark Gap Lengths 12 

Results — 

The Spark Gap Lengths 12 

Results, Ist — 

2nd — 

The Spark Gap Lengths 12 

Results — 

The Spark Gap Lengths 12 

Results, Is* — 

2nd — 

3rd — 

4th — 

The Spark Gap Lengths 12 

Results, 1st — 

2nd — 

8rd — 

4th — 

5th — 

The Spark Gap Lengths 12 

Results, Ist — 

2nd — 

8rd — 

The Spark Gap Lengths 12 

Results, Ist — 

2nd — 

8rd — 

4th — 

5th — 

6th — 

7th — 

Spark Gap Lengths 12 

Results — 

The Spark Gap Lengths 12 

Results, 1st — 

2nd — 

8rd — 

4th — 








































































































— . 




















•The Spark Gap Lengths 12 16 6 6 5 

Results, 1st — — * 

2nd — — ♦ 

" 3rd — __ — ♦ 

The Spark Gap Lengths 12 16 6 6 6 

Eesults, 1st — — ♦ 

2nd — 0—00 

'* 8rd ; — — * 

The Spark Gap Lengths 12 16 9 6 6 

Results, 1st _ _ _ _ 

2nd — — — ♦ 

3rd — — ♦ 

4th — —0—0 

The Spark Gap Lengths 12 16 10 6 6 

Results, 1st _- ♦ — 

2nd -« — — ♦ 

The Spark Gap Lengths 12 16 11 6 6 

Results — — ♦ 

The Spark Gap Lengths 12 16 10 10 10 

Results, Ist — — — — 

2nd — — _ • 

3rd : — — — 

The Spark Gap Lengths 12 20 10 10 10 

Results, 1st — — — 

2nd — — ♦ 

8rd — — • 

When 1 = 12, 2 = 9, 3 = 5i, 4 = 3i and 5= 1, the sparks 
were about evenly divided, except that 5 never sparked alone and 
always gave thread-like sparks when 2 sparked. These results 
are represented graphically in Fig. 6. 

Glancing now at the above table we notice : First. The difficulty 
that disruptive discharges experience in passing the coils, jump- 
ing as they do large air-gaps in preference to the more circuitous 
but infinitely better conducting paths afforded by the coils* 
Second. The tendency for discharges to divide into two or more 
paths, part passing across the first or second gap, and the remain- 
der through one or more coils to a succeeding gap, showing 
thereby that a single choke coil does not oflFer certain security 
against the passage of these discharges. Third. The uncertainty 
of the paths that will be selected during a series of tests where 
the conditions are maintained as nearly constant as possible ; in 
fact, it seems almost impossible to produce the same results twice 
in succession. It is, however, to be noticed that with these four 
choke coils in series and spark gaps intervening, the discharges 
are so thoroughly sifted out that only an occasional thread-like 



[May 16. 

spark finds its way across the last gap. With laboratory results 
such as these, it seemed fair to presume that results more or lofis 
similar might also be expected in practice. 

The plant selected for the trial of this apparatus was that of 
the San Miguel Consolidated Gold Mining Company, of Tellu- 
ride, Colorado, which is equipped with a 3,000-volt alternating 
current synchronous system, operating stamping mills, and fur- 
nishing current to the Telluride Electric Light Company. Theee 
points are situated among the mountains at distances varying 
from three to ten miles from the power house. Thiee separate 
circuits leaving the power-house extend over a wild and rocky 
country and in some places rise above timber line. In previous 
years every attempt to protect this plant from lightning had 
failed. During the summer months tw^o horses were kept con- 

c c c c c 



Fig. 7. 

fltantly saddled ready for emergencies consequent on lightning 
discharges, and at the motor and power-house it was common 
practice on the approach of a thunderstorm to lay out, ready for 
instant use, an extra armature coil, with all the necessary tools 
for handling the same. In one of the former types of arresters 
used in this plant forty fuses were blown inside of 60 minutes. 
The location of each bank of arresters was selected with par- 
ticular reference to securing permanently damp earth for the 
ground plate, the lines being led to this spot. The circuit was 
thus made to accommodate itself to the arresters rather than the 
arresters to the circuit. The apparatus was then installed in a 
specially constructed and weather-proof lightning arrester house 
(see Fig. 6) the arresters and choke coils being mounted on thor- 
oughly dried wooden frames and every precaation taken to insu- 


late these from the groand and from each other. In this manner 
also it was expected that the lightning discharges would be kept 
entirely out of the station. 

The connections inside the power-house lightning arrester 
house are all clearly indicated in Fig. 3. One main B. and S. 
No. 3 ground wire was used for all the arresters in each bank, 
unnecessary kinks and bends being studiously avoided. 

Fig. 8. 

The grounds which I used were of the most approved con- 
struction, and in this respect were in marked contrast to ground 
eonnections commonly found in practice. An old rusty casting 
or an abandoned pulley hooked onto the end of a tangled piece 
of scrap wire, and then thrown into a neighboring creek or the 
tail race of a mill, or a small iron spike driven conveniently into 
dry earth or sand, form ground connections not infrequently 

848 WURTS ON LiaHTmNO A RRESTBR S. [May 1«'. 

found in practice. But my work being only of an experimental 
nature, a thoroughly good ground connection was thought to be 
one of the essentials. The ground connections were therefore 
made as follows: First, a hole six feet square was sunk directly 
under each bank of arresters until permanently damp earth was 
reached ; Second, the bottom of this hole was covered with two 
feet of crushed charcoal (about pea size) — crushed coke would 
have answered equally well. Third, over this was laid 25 square 
feet of No. IB copper plate ; Foni*th, the ground wire was then 

Fig. 9. 

^rmly soldered all the way across the ground plate ; Fifth, the 
plate was now covered witli two feet of charcoal ; and sixth, the 
hole was filled in with earth, using running water to settle. In 
one instance permanently damp earih could not be reached; 
water was therefore brought from some considerable distance 
through an iron pipe and run into the upper earth of the ground 
hole. In this manner the entire ground construction was main- 
tained constantly damp. 

Observations were taken by competent men at each bank of 




arresters during the entire lightning season, and the results ob- 
tained indicate that the discharges occurred most frequently over 
the second arresters ; many passed over the third arresters ; very 
few, however, over the first or fourth. The writer personally 
watched one of these banks of arresters through severe thunder- 
storms and in every instance the discharges noticed by him were 
seen to pass across the second series of spark gaps. The dis- 
charges followed each other across the cylinders with great 
rapidity, making peculiar and often startling sounds, very similar 
to the cracking of a teamster's whip, but in no instance was there 

Ol ground 

a fuse blown, or damage done to the arresters. Now, these facts 
are not only of great practical importance, but are also exceed- 
ingly interesting when studied in connection with the results 
already mentioned as having been obtained with choke coils and 
spark gaps in my laboratory experiments. At the end of the 
lightning season the non-arcing metal cylinders of the arresters 
were carefully inspected and the confronting sides found to be 
covered with minute black spots where the discharges had passed 
from cylinder to cylinder. These spots were often centered with 
very small, smooth exposures of the metal, but in no instance 
was there any indication of beading or fusing together of the ad- 
jacent cylinders. 


The net results of this lightning arrester experiment are most 
satisfactorily summed up in the following letter written by Mr. 
P. N. Nunn, Electrical Engineer of the San Miguel Consolidated 
Gold Mining Company. I feel greatly indebted to Mr. Nunn 
for the kindly assistance he has rendered in carrying out these 
tests, and take this opportunity to again thank him for his valu- 
able suggestions and the pains-taking care with which the instal- 
lation was made. 


Telluride, Colo., October 12th, 1898. 
Mr. Alexander Jay Wurts, 
Pittsburgh, Pa. 

My Dear Sir : — In reply to your inquiry respecting the results obtained from 
your lightning arresters in the operation of our electric power transmission 
plant, we take pleasure in making the following statement : 

At the present time, as you are aware, our plant consists of a power station at 
Ames, equipped with Westinghouse alternating current generators of 1100 horse 
power capacity, which supply current for synchronous motors in three stamp 
mills at distances of two, throe and ten miles respectively, and for lights in the 
town of Telluride about eight miles distant. The pole line runs over the moun- 
tains in altitudes varying from 8,800 to 12,000 feet above the sea level, travers- 
ing at different places bare ridges of mountain divide, and large tracts of mag- 
netic mineral. It is thus petjuliarly exposed to lightning in a district where 
lightning is of extraordinary frequency and force at certain seasons of the year. 

The difficulties of the situation are further aggravated by the fact that we 
generate and utilize without transformation, except for lighting purposes, an 
alternating current of 3,000 volts. 

Despite the use of an overhead grounded wire on our pole line, and the best 
arresting apparatus we could procure, we suffered continual interruptions du- 
ring the lightning seasons of 1891 and 1892. On one occasion five armature coils 
were burned out in a single stx>rm. With any other form of armature this 
would have meant five burned out armatures ; but with the toothed armature 
of your machines it represented the cost of five new coils and a day's delay. 
The frequency of the discharges of lightning was so great that the insulation in 
the highest grade of cables and cores throughout the entire apparatus became so 
honeycombed with perforations as to give rise to continual leakage, grounds and 
short-circuits, requiring constant and expensive repairs and causing prolonged 

Since putting in your non-arcing metal arresters in connection with your sys- 
tem of specially designed choke-coils, we have passed through the lightning 
season of 1893 without a particle of lightning having passed to our knowledge 
beyond the arresting apparatus, without a shut-down, without the loss of a coil, 
and without a single perforation of insulation. The experience of this season 
has given us the greatest confidence in the efficiency of your apparatus as a pro- 
tection against lightning. 

(Signed) P. N. Nunn, 

Electrical Engineer. 


Pabt II. — Pbotbction Against Lightning on Circuits of 
ANY Potential. 

A system of protection against lightning discharges has been 
designed by the writer, which is applicable to circuits of any 
potential, and although this system has not yet received a prac- 
tical test, the indications are that it will prove efficient. 

The proposition is to connect in series with the circuit, and at 
frequent intervals, a system of properly constructed choke coils, 
the expectation being, that the energy stored in the circuit in the 
form of static electricity will, at moments when there is a ten- 
dency to a disruptive discharge, dissipate itself into heat through 
the electrical surgings which will be set up between and among 
the several choke coils. In Fig. 7 there is represented a power 
transmission circuit provided with this system of protection 
against lightning. 

The theory upon which these predictions are based, is more or 
less familiar to every electrical student. There exist, however, 
differences of opinion regarding some of the points involved. 
Many of my impressions are derived from personal observation, 
and through these I have been led to believe that, in many cases, 
electric circuits become statically charged by contact with the 
neighboring charged atmosphere, that is, by conduction from it. 
The charge on the line, no doubt, leaks to earth, so does the 
charge in the atmosphere, but the two are maintained at practi- 
cally the same potential. 

The potential of the atmosphere surrounding the wires of 
overhead electric light and power circuits is not very high. At 
the top of Washington monument, Washington, D. C, the dif- 
ference of potential between the atmosphere and the earth dur- 
ing the thunder storms is about 3,000 volts. If then the 
potential of an aerial wire is the same as that of the atmosphere 
intimately surrounding it, the immediate source of danger from 
the static strain will be inconsiderable. When, however, a 
lightning discharge occurs from the clouds, this charged condition 
of the wire becomes unbalanced, the atmosphere has been dis- 
charged and its potential has suddenly sunk to zero. The static 
charge in the wire having lost the support of the previously 
charged atmosphere now seeks an equilibrium, and in so doing 
sets up electrical waves which travel to the extremities of the 
system, or to points of great resistance, and are there reflected 


to other parts to be again reflected, and so on. At these points 
of reflection there is an enormous strain, and a consequent ten- 
dency to ^^ side flash " so often causing the damage to insulation 
which we are seeking to avoid. Such electrical disturbances 
consequent upon a lightning discharge can be observed in wire 
fences and in tramway rails. In high altitudes even the wet 
rocks are seen to become luminous, giving off brush discharges 
at moments of electrical disturbance, and the human body will 
often feel that peculiar sensation familiar to those who handle 
influence machines, namely, a sudden and cool draught when an 
existing condition of electrical strain is broken down. 

It is then at these points of reflection that the damage is done, 
and that we get the impression of a very high potential. An 
armature insulation is pierced by the discharge, the dynamo cur- 
rent follows, there is a great flash accompanying the short-circuit, 
several fuses let go and the superintendent is informed that 
lightning entered the station. As a matter of fact, it is probable 
that the discharge has made a hole in the insulation no larger 
than the prick of a pin or perhaps that of a pin head, wKich in 
most cases is greatly enlarged by the dynamo current. 

There are other methods, however, by which circuits probably- 
become charged; namely, by static induction from clouds and by 
dynamic induction from cloud discharges. It is probable that 
these also set up electrical surgings in the circuit and that the 
danger to insulation occurs at points of reflection. I am also in- 
clined to believe that, although a line is seldom, if ever, struck 
by a direct lightning discharge, it occasionally becomes charged 
by some of the ramifications which are often seen to accompany 
a lightning stroke. 

Fig. 8 is an example of what might be called a direct discharge, 
and to the best of my knowledge there is no evidence to show 
that such discharges strike electric wires.. In Fig. 9, there is 
represented a lightning discharge accompanied by ramifications 
which wander off in a seemingly aimless manner, but which, no 
doubt, find their way to bodies or strata of air variously electri- 
fied. I am inclined to believe that at times, some of these rami- 
fications find their way into electric circuits. 

A curious freak which came under my observation last summer 
is illustrated in Fig. 10. t represents an overhead trolley wire, 
on either side of which are wooden poles, h is a bell-shaped in- 
sulator made of compressed mica and shellac. These insulators 



easily withstand an electric strain of 12,000 volts, r is an iron 
ring holding the span wire to the pole. . b is a branch circuit 
feeding current to a group of lamps o^ and l is a lightning ar- 
rester in its discharge circuit, o^ is a second group of lamps. 
The distance between h and b is about 50 feet. After a violent 
thunder storm it was noticed that one of these poles had been 
shattered from the top, down to the iron ring, the remaining por- 
tion being uninjured. This had been done by lightning, and in 
th*i opinion of the writer, by one of the ramifications to which 
allusion has already been made. In any case, this discharge^ 
whatever it may have been, passed over the span wire to the bell 
insulator h, piercing it and breaking it into three pieces, then 
travelled along the trolley wire to b, where it apparently divided, 
one part passing to the group of lights g', breaking them all, ten 
in number, and the other part to earth through the arrester l, 
without in any way interfering with the group of lights o^ It 
is quite remarkable to note that none of the parts damaged by 
this discharge showed any indications of heat. 

During the past summer I have watched many discharges 
enter a generating station over idle wires and pass to earth across 
simple carbon spark gaps provided with No. 18 copper wire fuses. 
The discharges gave a crackling sound similar to that of dis- 
charges from a Leyden jar, and in some instances where I had 
placed pieces of tissue paper between the electrodes of the spark 
gaps, the papers were perforated with small holes. In one in- 
stance only which came under my observation did the copper 
wire fuse melt. An apparently prolonged discharge passed over 
one of the spark gaps with a hissing sound, raised the tips of the 
carbon electrodes to a white heat and fused the copper wire cut- 
out, the time taken being approximately two seconds, which 
would indicate in the neighborhood of 160 amperes. I believe 
this discharge to have been part of a true lightning discharge — 
one of its ramifications— but in the great majority of cases the 
discharges are small, and in this respect bear no comparison to 
cloud discharges. 

Now, if the "electrical surgings" theory be correct, I believe 
that these dangerous points of reflection can, by means of pro- 
perly distributed and effective choke coils, be confined to long 
lines and made to wear themselves out. as it were, between the 
coils. In this manner frequent points of reflection would be dis- 
tributed over the system. Primary waves set up during electri- 


cal disturbances would be broken into smaller waves, whieb, 
surging back and forth between the coils or points of reflection, 
would finally become dissipated and their energy pass off into 

Fig. 11. Fig. 18. 

The number of coils which it would he necessary to use for a 
given length of circuit has not yet been determined, but the 
writer would suggest placing four to each mile of single wire. 
For convenient accomodation on the poles these can be arranged 
alternately on the two legs of the circuit, thus avoiding two coils 
on any one pole. 

Should such a system of protection against lightning be found 
efficient, its many advantages over the discharge circuit method 
would be obvious, particularly in a country where good ground 
connections are costly, and often impossible to construct. 

The general form and dimensions of these choke coils is a mat- 
ter of considerable importance. Dr. Lodge states, I believe, that 
for disruptive discharges a flat spiral will offer maximum impe- 
dance with a given length of wire. To the best of my knowledge, 
however, Dr. Lodge makes no mention of the number of turns 

Fig. 12. Fio. 14. 

which may be advantageously used. I have found by experiment 
that the impedance or resistance to the passage of disruptive dis- 
charges does not continuously increase with the'number of tarns, 
but that a critical point is rapidly reached, beyond which addi- 
tional turns do not add appreciably to the impedance of the coil. 




The critical point was determined in the following manner. A 
large flat coil was constructed, having the following specifications : 

SisBe of wire No. 

Number of turns. , 84 

Outside diameter . 30' 

Inside *• 3" 

The wire was carefully insulated so that the discharges could 
not pass between consecutive convolutions. 

This coil was then connected up in the usual manner for de- 
termining impedance^ the general arrangement of the apparatus 
being shown in Figs. 11, 12, 13 and 14, where b is a variable 
shunt spark gap, one tenninal of which is permanently connected 
to either terminal of the coil, while the other is provided with 

— — . 

1 Figs 










Z 5 







-- ( 




. y 

- ■ y * - ' 






>. - 



Z 15 





1 = 




/ . 

! • 





— ■ 




NO. O 


48 SHI 


BY B. 

20 26 30 3B 

a sharp metallic point fastened to a short flexible cord. The 
sharp point was used to pierce the insulation of the coil, thereby 
reaching the copper of any convolution, and also in this manner 
providing a means for shunting any desired portion of the coil 
by the spark gap b. Spark gaps a and b were varied by means 
of a thirty-second of an inch screw thread, so that the dimensions 
of these gaps are given in thirty-seconds of an inch. 



[May 16. 

Ektch determination was made by sknnting with the gap b that 
portion of the coil whose impedance was desired, and then vary- 
ing the length of b until the discharges were about evenly divided 
between the coil and the gap. In the following table are given 
the values of b and the number of convolutions shunted by the 
gap in each determination. 

No. of Turns. 

1st B. 

2Dd B. 

3rd B. 

4th B. 

5th B. 

































5 , 

































20 J^ 




























































In the first colunm are given the number of convolutions 
shunted by the spark b. 

Column 1 B gives the values of b under conditions shown in 
Fig. 11, with A equals 12 and with rounded electrodes at b. 

Column 2 B gives the values of b under conditions shown in 
Fig. 12, with A equals 12 and with rounded electrodes at b. 

Column 3 B gives the values of b under conditions shown in 
Fig. 13, with A equals 12 and with rounded electrodes at b. 

Column 4 B gives the values of b under conditions shown in 
Fig. 14, with A equals 12 and with sharp electrodes at b. 

Column 5 B gives the values of b under conditions shown in 
Fig. 13, with A equals 15 and with rounded electrodes at b. 

For convenience, these results are graphically represented in 
Figs. 15, 16 17, 18 and 19, and we note, first, that in each case 
a positive maximum impedance is reached, beyond which addi- 
tional tui'ns do not affect the results ; second, that with the ex- 




ception of the results shown in Fig. 15, the impedance does not 
increase beyond abont the 17th turn ; third, that with both ter- 
minals of the coil permanently connected to the discharge circuit 
(see Fig. 15), the increase of impedance is more gradual than 
when only one terminal is so connected ; fourth that when per- 
manent connection is made to the outside of the coil. Fig. 16, 
the increase is more rapid than when permanent connection is 
made at the center, Fig. 17, in other words, a single turn on the 
outside offers more impedance than a single turn nearer the 
center ; for equal lengths of wire, however, the turns near the 
center offer greater impedance : fifth, that increasing a slightly 
decreases the number of turns, Fig. 19 ; sixth, that using points 

Fig. 20. 

at B, instead of knobs, does not materially change the results, 
other than to make the path selected by the discharge somewhat 
more uncertain, as will be noticed by the irregular curve shown 
in Fig. 18. The coils which I have constructed have been wound 
witU reference to the critical point. 

Dr. Lodge haA also experimented with such coils in connection 
with iron cores, and found that the impedance is not appreciably 
affected by their introduction. I have also experimented in this 
line, and have naturally surprised myself by obtaining quite 
different results. It is, however, to be supposed, in view of Dr. 
Lodge's masterly study of this subject, that my conditions have 
in some way differed from his. I found that upon the introduc- 



[May 16, 

tion of a small bundle of iron wires into the core of a coil, the 
impedance to disruptive discharges was reduced neaily 2ft per 
cent. The cause of this was at onCe made apparent by the 
beautiful sparks which were seen to appear among the iron wires 
of the core upon the passage of each disruptive discharj^. 
These iron wires, of course, form among themselves clcMaed 
secondaries to the primary coil, and in this manner also very 
beautifully illustrate the oscillatory character of the dit-eharge. 

A convenient mechanical analogy for this electrical sui^ngs 
system may be found in hydraulics. Referring to Fig. 20 Ifit 
M represent a water main closed at either end ; f p a supply 
and outlet ; d d etc. perforated elastic diaphragms If now an 
impulse be imparted to the water at e, as by a blow, a wave will 



O Q 

Fig. 21. 

tend to travel from one end of the main to the other, and if it 
were not for the diaphragms, this wave would either burst out 
the opposite end of the pipe or be reflected back and forth un- 
til the energy of the wave had become transformed into heat. 
The presence of the diaphragms, however, will tend to break up 
the initial wave and confine the surgings to comparatively sfnall 
portions of the pipe. At the same time the perforations in ihe 
diaphragms allow of a continuous flow of water under pressure. 
In the electrical system the choke coils are supposed to break up 
the electrical surgings, much as these diaphragms break up the 
water surgings, and at the same time the coils do not materially 
interfere with the passage of the dynamo current. The coils 
cause points of reflection to occur where an excessive static strain 
can do no harm. The ends of the circuit, which are the vital 




parts of an electric power transmiBBion system, are thus shielded 
by the coils and the energy of the static charge is harmlessly 
transformed into heat. 

It has, however, been mentioned in Part I. that coils are not 
absolutely impervioas to disruptive discharges. A discharge 
entering a coil meets with continuous resistance and is finally all 
or partially reflected ; in other words, a coil is not a stone wall, and 

Fig. 22. 
does not necessarily confine the point of intense electrical strain 
to the first inch or two of the coil. The discharge penetrates the 
coil and often causes " side flash " to occur well within its inte- 
rior. In my m.echanical analogy therefore I have represented 
this yielding opposition, as it were, by elastic diaphragms. 

Pabt III. — Discriminating Lightning Abrkstkrs. 
Tke Condenser Lightning Arrester. — The discovery and prac- 
tical application of non-arcing metal to alternating current cir- 



[May 16, 

cuits about two years ago,* has indicated the possibility of 
constructing a discriminating lightning arrester, as it were, for 
direct current circuits ; that is, an arrester which should not re- 
quire the usual automatic circuit interrupting attachment, but 
which, by virtue of its material or construction, should allow 
static electricity to pass and prove an effectual barrier to the 
dynamo current. 

The first step taken in this direction was to carefully analyze 
the conditions, and the general conclusions arrived at were as 

^ r^s^ 



Fig. 28. 

follows : A circuit becomes charged in various ways with static 
electricity tending to earth. These charges are, in a majority of 
cases, small and of no considerable intensity. The surgings in the 
system find points of reflection which also become points of 
greatly increased tension. The earth is the great reservoir (to 
use common language) for these discharges. This reservoir is, 
however, unnecessarily large for the accommodation of line dia- 
charges. Might not smaller reservoirs be made — ^little earths 
insulated from tlie mother earth ? If the circuit were connected 
i. Tramsactionb, vol. ix , p. 102, 1892. 




<lirectly or through spark gaps to such little earths, these danger- 
ous snrgings might be broken up and the line safely discharged 
without a possibility of the dynamo current following. Each 
spark gap in each of such discharge circuits would then form a 
discriminating lightning arrester, but these little earths would be 
nothing more nor less than one coating of a condenser — the 
mother earth a common coating to them all. Why not then use 

Fig. 24. 

condensers, connecting one side to line, the other to earth through 
a spark gap 'i 

One difficulty immediately presented itself. After the con- 
denser had become charged how was it to become discharged ? 
To be successful it must be self-discharging, and not only this, 
but the discharge must take place in such a manner that no 
dynamo current should follow. Therefore, to discharge the con- 



[May 16^ 

denser disniptively was at once out of the question. Experi- 
ments in this line led lirst to the application of a wet string to 
the terminals of a condenser, the idea being to leak out the 
charge through an ohmic resistance sufficiently great to prevent 
an appreciable flow of dynamo current. A two m. f. condenser 
provided with a wet string leak was treated with violent disrup- 
tive discharges from a battery of Ley den jara, and upon imme- 
diately applying the tongs to the terminals of the condenser after 
the crack of the discharge, not the smallest trace of a charge 
could be ^ieteeted. When the string was removed or had be- 
come dry the charge was r etaine d. Evi<fefltly a wet string 
would not answer as a permanent leak. Various compositions 

Fig. 2o. 

of plumbago with moulding sand, red lead and pla8ter-of-pari& 
were pressed into a tube and used, but these all proved uns: tis- 
factory, being unreliable. In many instances this composition 
leak would, before testing with the condenser, have a resistance 
of 30,000 ohms, and after a single discbarge it would be found 
that this resistance had increased to many hundred thousand 
ohms. This was, perhaps, due to the flying apart of the plumbago 
particles under the influence of the discharge, and so breaking 
the continuity. Finally, a pencil mark over ground glass was 
suggested and this was found to work admirably. A medium 
pencil was rubbed back and forth over a strip of ground glass^ 




making a narrow shining strecdc having a resistance of from 
40,000 to 50,000 ohms. Rubbing with the hands did not seem 
to appreciably change this resistance. Broad 4>]ack pencil marks 
were made on the ends for better contact, and connection to the 
terminals of the condenser was obtained through aluminium foil, 
both glass and foil being protected on the bottom by the wooden 
case of the condenser, and on top by a small inverted wooden 
trough. A condenser provided with such a pencil mark leak, 

Fig. 26. 

was now connected to a 500-volt direct cuirent circuit and to 
apparatus, as shown in Fig. 21. l was a 50ii-volt direct current 
genemtor; l one leg of the circuit, which may represent a trol- 
ley wire ; o the other leg of the circuit, and which may repre- 
sent the ground return : k the two m. f. condenser with its high 
resistance leak Z / c a small spark gap in series with the conden- 
ser, and in the discharge circuit ; b was a f| inch spark gap 
over which disruptive discharges would pass from the batterj- of 



[May 16. 

Leyden jars (11), and in this manner suddenly charge the hne l. 
The most violent disruptive discharges that could be obtained in 
the laboratory were unable to damage either the generator or 
the condenser. A small spark gap, a trifle larger than c, con- 
nected either in series or in shunt to the generator failed to take 
any of the discharges, thus demonstrating the ease with which 
the discharges were received by the condenser. Such tests were 
continued for half an hour at a time, the discharges following 
each other in rapid succession, but the condenser was ever ready, 
being kept constantly discharged by the high resistance leak. 
Of course, the resistance of the leak was sufficient to prevent 
the formation of an arc at c. The terminals of the leak were 
also too far apart to permit the condenser to discharge disrup- 
tively. This device ensures all the requirements of a discrimi- 

FiG. 2T. 

nating lightning arrester, and in this form seemed admirably 
adapted for station and indoor use on 500- volt direct current 

For line or outdoor ase the condenser was placed in a suitable 
cast-iron box, one terminal of the condenser being grounded to it, 
while the other was led out through a specially designed and 
water-tight bushing. If then this iron box were buried in damp 
earth, as a ground plate, so to speak, the outer terminal connected 
to the lower electrode of a small spark gap placed on a pole, and 
the upper electrode of the gap connected to the line, the combin- 
ation would constitute a discriminating line lightning arrester. 
See Fig. 22. 

Practical tests have been made during the past summer with 


both statioD and line condenser lightning arresters, and the results 
obtained have been most gratifying. The plant in which the 
apparatus was installed was that of the Denver Tramway Com- 
pany, Denver, Colorado, in a locality where lightning storms are 
particularly severe and of frequent occurrence. This plant ex- 
tends over a vast amount of territory and no attempt was made 
to protect it as a whole with these arresters. The experiences of 
this company with automatic lightning arresters on the line had 

Fig. 28. 

been extremely unsatisfactory, and as a tinal measure they had 
resorted to simple carbon gaps liberally distributed over the sys- 
tem, depending upon the station circuit-breakers to interrupt the 
short-circuits. This combination, however, worked satisfactorily 
near the station only; at any considerable distance therefrom, the 
drop on the line was such, that even a short-circuit across these 
spark gaps failed to trip the breakers. The arc therefore con- 
tinued until it had burned itself out, which in many cases was 
not accomphshed until the top of its wooden pole had been 
burned off. 


The installation of theee condenser lightning arresters consisted 
of five arresters on the line and 44 spark gaps with 11 condensers 
in the station. The station spark gaps were also provided with 
two specially constructed choke coils for each feeder. The orig- 
inal arrangement of this apparatus is shown in Fig. 23. a is the 
generator ; f f etc. the feeders ; 1, 2, 3, 4, etc. the 44 spark gaps 
alluded to; c 1, c 2 the two choke coils in series with each 
feeder ; s represents the circuit-breakers and k Keystone light- 
ning arresters ; c is a bank of four 2 m f condensers, making a 
common ground for the 44 spark gaps ; t is a tank lightning 

Fig. 29. 

arrester ; o is an overhead ground return ; 5 a spark gap in the 
ground wire of the 44 spark gaps. A tell-tale piece of tissue 
paper was placed in this gap, which, becoming punctured, would 
at once indicate and register the passage of a ditcharge across 
any of the 44 spark gaps. 

The first thunder storm which occurred after this apparatus 
had been installed gave unlooked for results. The tell-tale paper 
at 5 failed to indicate any discharge whatever— the spark gaps 
1, 2, 3 and 4, which were placed in the cupola were examined 




iind many of these fouud to be badly burned. At first thought, 
this indicated some path to earth other than that provided 
through gap 5 to the condensers. Tests for a ground, however, 
failed to prove this to be the case. A succeeding storm repro- 
duced these same strange results. A more careful study of the 
problem, now disclosed the fact that as the circuit-breakers were 
frequently thrown open during thunder storm?, the feeders 
which were thus opened became ground wires, being grounded 
through their respective motors. Consequently, live feeders dis- 

Fio. 80. 

charged into these dead or grounded feeders and vice versa^ form- 
ing arcs which burned the carbon electrodes of the several spark 
gaps according to the amount of current taken by the respective 

Fresh carbon electrodes were subsequently provided, and a 
single condenser connected to each group of spark gaps on the 
individual feeders, which arrangement would prevent the possi- 
ble re-occurrence of arcing between feeder?. 

The line arresters had, however, in the meantime been care- 


[May 1«, 

fully watched, and after every storm the tell-tale papers were 
collected and found to be perforated with a greater or less num- 
ber of small holes, each hole being slightly discolored around the 

Tiie sensitiveness of these condenser arresters was particularly 
noticeable, in that the tell-tale papers were found to be punctured 
at the slightest provocation, when in fact no considerable thunder 
storm had passed over the lines, and yet, sensitive as they were 
to slight charges on the line, it is remarkable to note that the sim- 
ple carbon spark gaps belonging to the local company, which have 
already been mentioned, and which provided a gap | inch between 
electrodes, frequently received discharges in preference to the 
minute spark gap of a neighboring condenser line arrester. Such 
occurrences coupled with many others of a similar nature point 

Fig. 31. 

to the existence of nodal points, and the necessity of distributing 
line arresters at frequent intervals over the system. 

In fact a lightning arrester connected directly to the terminals 
of a generator or motor offers no absolute guarantee of protection 
to this particular piece of apparatus. The presence of the arres- 
ter simply offers an opportunity for discharge. The discharge 
may occur in the armature, or it may occur through the arrester, 
according to the particular conditions existing at the time of each 
discharge. The arrester could have a comparatively large spark 
gap, and the breaking down strain of the armature insulation be 
low, and still the discharge might prefer the large gap to the 
weaker insulation, while on the other hand the arrester could 
have a very small spark gap and the armature be provided with , 



the highest grade of insulation, yet in some cases this insulation 
would be pierced by the discharge in preference to the small 
spark gap of the neighboring arrester. A striking example of 
this possibility is illustrated in Fig. 24. a is a type of strain-wire 
insulator which is ordinarily capable of withstanding from 15,000 
to 20,000 volts. B shows a wire connecting an overhead return 
to the ground wire return. The distance between wire b and the 
iron hoop holding the strain wire is about one inch. During a 
violent thunder storm the insulator a was punctured by a dis- 
charge which passed from the trolley wire through the insulator 



Fig. 32. 

to the iron hoop, and thence across the one-inch air space to the 
grounded wire b, and this very high ohmic resistance path was 
taken in preference to a neighboring line arrester having a small 
spark gap. Had an arrester been connected at this point, there 
is no question but that the arrester would have taken the dis- 
charge, but by reason of the nodal points which are formed along 
the line by the electric surgings, a lightning arrester 100 yards 
away, although it is liable to take a large proportion of thejdis- 
charges, does not by any means offer an absolute guarantee of 


protection to a neighboring piece of apparatus. A large number 
of line arresters, that is, a large number of opportunities for dis- 
charge, is the surest means of securing efScient protection. 

The results obtained with these condenser arresters have ex- 
ceeded my expectations, and in my opinion have thrown consid- 
erable light on the intensity and volume of discharges commonly 
found in electric light and power circuits. During my two 
months' stay in Denver not a single condenser was disabled, nor 
were any of the tell-tale papers burned. I have with me a few 
of these perforated papers which T shall be glad to have you 
inspect. I was not present in Denver after the burned out spark 
gaps in the station had been replaced, and am therefore not in 
possession of any further data from that source. But, in Colorado 
Springs, where I spent the next following six weeks, I connected 
three of these condenser arresters in the station of the Colorado 

Fig. 38. 

Springs Bapid Transit Railway Company, and was treated to 
many violent thunder storms, through all of which, these arresters 
showed a wonderful capacity for repeatedly and rapidly discharg- 
ing the line. Through many of these storms the discharges 
passed the spark gaps as many as twenty times a minute, com- 
pletely riddling the tell-tale papers. 

I may, therefore, say with emphasis, that the condenser light- 
ning arrester has proved itself most eflScient in points of sensi- 
tiveness, durability and general reliability. In actual service it 
has demonstrated the successful construction of a truly discrimi- 
nating direct current lightning arrester. 

The NonrArcing Railway Lightning Arrester. — I have, how- 
ever, designed a lightning arrester which is much smaller, 
cheaper and, perhaps, in every way more desirable than the 
condenser arrester. It is also a discriminating lightning arrester. 




I had frequently noticed what is probably familiar to many of 
jou, namely, that a disruptive discharge will leap over a non- 
conducting surface much more readily than through an equal air 
space. The non-conducting surface seems to form an entering 
wedge, as it were, through the air, so that this being already 
partly split or ruptured, the discharge has but to further sepa- 
rate the air from the non-conducting surface instead of boring 
its own path through it. A pencil mark over a rough piece of 

Fro. 84. 

glass or unpolished marble still further reduces the breaking 
down strain. 

But, to avail myself of this fact in the construction of a light- 
ning arrester was a problem over which I pondered for some 
time. My design was to bring electrodes located in a discharge 
surface, near enough together to form a lightning arrester spark 
gap, and at the same time to avoid the passage of dynamo cur- 
rent when the electrodes were connected to the terminals of a 


500-volt direct current generator. I reasoned that a dynamo arc 
to be maintained must be fed by the vapors of its electrodes. 
To prevent an arc, the formation of such vapors must be sup- 
pressed. My first attempt in this direction proved successful* 
I drew a pencil mark about two inches long over an unpolished 
piece of marble, covered this with a second piece similar to the 
first, and, having previously slipped between the two marbles,, 
pieces of aluminium foil as terminals to the pencil mark, I bound 
the whole together with twine. These terminals were now 
connected to the terminals of a five hundred-volt direct 
current generator and disruptive discharges caused to pass be- 

FiG. 35. 

tween the marbles and over the pencil mark. A one-ampere 
fuse was connected in the dynamo circuit. No current follow- 
ing these discharges, the terminal foils were brought successively 
nearer together, testing each time for the passage of dynamo 
current. "Vyhen the electrodes had reached a distance of a quar- 
ter of an inch from each other, the fuse was blown. The termi- 
nals were now placed a half-inch apart, and oft repeated tests 
failed to establish a short-circuit. The dynamo was now cut out, 
and upon resting my hand on the upper marble, while the dis- 
charges were still passing, I noticed a considerable mechanical 
shock, and when the twine was removed, the upper block was^ 


thrown off. In consequence of this, it seemed advisable to pro- 
vide more space for the discharge. A small groove was, there- 
fore, cut in the lower marble from one electrode to the other, 
and well blackened with a lead pencil mark. Discharges now 
failed to produce the above mentioned mechanical shock, or to 
throw off the cover. It was, however noticed, that after several 
discharges had passed, this pencil mark disappeared, having been 
dissipated and apparently scattered over the surfaces of the two 
marbles. To overcome this difficulty a piece of wood was laid 
into the lower marble between the electrodes, and into this a 
shallow groove was burned. This construction, which is shown 
in Fig. 30, seemed to possess some advantages over the one al- 
ready described — ^it suggested more lasting qualities. Various 
materials were now tested into which one or more discharge 
grooves might be burned, such as liber, felt, leather, ivory, box- 
wood, celluloid and others, but most of these proved unsatisfac- 
tory for various reasons. With fiber, the charred surface was 
quickly worn away, ivory chipped off in small pieces, both 
leather and felt crumbled away. Lignum vitse, however, proved 
to be a most excellent material. In the final form adopted for 
this arrester, both upper and lower blocks were made of this 
material, thus enabling the discharge grooves to be burned into 
the lower block itself, and avoiding the necessity of inserting a 
discharge piece between the metal electrodes. This arrester for 
station use, is illustrated in Figure 25 ; for line use in Figure 
26. The blocks are 3 inches wide by 3^ inches long and 1 inch 
thick. Two brass electrodes each 1 inch wide are laid into the 
lower block, flush with its surface, the distance between elec- 
trodes being i inch. The charred grooves are nine in number, 
and about ^ inch wide by ^ inch deep. 

Another and more simple form of this arrester was also con- 
structed. A hole was bored through a solid block of marble, the 
center of which was then filled with a cylindrical block of hard 
maple, having grooves burned in on the sides. Solid brass cylin- 
drical electrodes were then inserted in either end, making a snug 
fit. But in practice, these marbles were in many cases split open 
by the expansive force of the discharge, thus demonstrating the 
necessity of the vent which is obtained by clamping two surfaces 
together, and between which the discharges may pass. 

This device, like the condenser arrester, constitutes a strictly 
discriminating lightning arrester. In regard to its action I have 


been asked why a discharge should find an easier passage across 
a conducting film, than through a non-inductive conductor hav- 
ing the same ohmic resistance as the conducting film. My con- 
ception of the case is as follows : When a discharge passes 
through a conductor of more or less ohmic resistance the time 
of discharge is considerable, there is a great strain from all parts 
of the charged surfaces during the time of passage, and there 
will be a tendency to discharge or " side Hash " along paths nor- 
mal to the conductor. The passage of the discharge may be 
likened to the passage of tangible matter through a dense fluid 
— there is a gradual yielding of the opposing resistance, but noth- 
ing is broken. When, however, a discharge passes over a 
conducting lilm as described, there is a sudden breaking down or 
giving way of the dielectric, and this is aided by the presence of 
the conducting film. The film, however, does not act in the 
sense of what is commonly called an electric conductor, but as a 
wedge, splitting the dielectric preparatory to the passage of the 
disruptive discharge. 

The difference between these two cases is very clearly illus- 
trated by the discharge of a Leyden jar provided with a pith 
ball electrometer. Take the arrangement shown in Fig. 27; 
while the machine is charging the battery of jars, the increasing 
charge can be observed by the deflection of the pith ball, until 
finally a disruptive discliarge takes place across the arrester or 
spark gap a, and the pith ball is seen to fall back suddenly, in- 
dicating in this manner complete discharge. If, however, the 
gap A be removed and the discharge be caused to pass either 
through the inductive coil c, or in its stead a non-inductive high 
ohmic resistance, the pith ball at the moment of discharge will 
fall part way only, indicating thereby an incomplete discharge. 
The sound of the discliarge in the latter case is also very diffe- 
rent from that in the former — it is more like a thud, suggesting 
opposition to the passage, whereas in the former case the sound 
is that of a crack, indicating something instantaneous and com- 

The non-arcing property of the arrester is easily understood ; 
the conducting vapors which are necessary to the formation and 
maintenance of a dynamo arc are suppressed by the cover which 
fits tightly over the metal electrodes. In Fig. 28 the arrester is 
seen in operation. The terminals of the arrester are connected 
to the terminals of a 500-volt direct current generator. The 


cover is of glass so that the discharges may be seen. In the 
upper part of the figure, five 100-volt lamps in series indicate the 
dynamo pressure ; just below this and to the left is a long hori- 
zontal 5-ampere fuse ; to the left of the arrester is a spiral choke 
coil connected in the dynamo circuit, and interposed between the 
arrester and the generator. This coil is very similar to those 
which I used in my Colorado experiments. The disruptive dis- 
charges immediately below the arrester, represent the means used 
for suddenly charging th§ dynamo ciicuit. The discharges 
across the arrester are distinctly seen through the glass cover. 
When, however, this cover is removed, the first discharge estab- 
lishes a short-circuit and the fuse is instantly blown, as seen in 
Fig. 29. 

The relative ease with which a discharge will leap over such 
a surface in preference to a few turns of large copper wire, is 
illustrated in Fig. 30, which is taken from a photograph. Fig. 
31 shows the arrangement of the apparatus more clearly, a is 
an arrester such as I have been describing and is provided with a 
clear glass cover so that the discharges may be seen, c is a choker 
coil connected in parallel to a, it is 16 inches in diameter and has 
17 turns of No. copper wire. Discharges from a battery of 
Leyden jars invariably pass at a in preference to the path c, as 
shown in the photograph. 

A thorough test of these arresters has been made in both Den- 
ver and Colorado Springs during the past summer. Fig. 32 rep- 
resents the equipment used in Denver. There were ten feeders^ 
each feeder being provided with three arresters placed three feet 
apart. These are indicated at 1, 2 and 3. The object of using 
three arresters to each feeder was to avoid nodal points, s rep- 
resents the circuit-breakers ; t is a tank arrester ; s 1 the dis- 
charge circuits of the tank arrester and 4 represents spark gaps 
in these discharge circuits. None of the arresters were provided 
with tell-tale papers, and although they were carefully watched 
during thunder storms, no indications were observed of passing 
discharges. After the first storm following their installation the 
writer removed the covers of the upper ten, and of these, six 
showed marks of discharge; the remaining twenty were con- 
structed on the " solid marble " pattern and were consequently 
difficult and unsatisfactory to inspect. One of the upper ten 
arresters was subsequently dismounted and photographed, and 
Fig. 33 is an excellent copy clearly showing the smudge formed 
by the discharge over the marble surfaces. 


The only mishap which occurred to any of these arresters wan 
the explosion of one of the " 8olid marble " type. No experi- 
mental line arresters of this type were used on the Denver 
plant. In Colorado Springs, however, 25 were installed on the line 
and 24 in the station. Some of these were of the divided kind 
(see Fig. 25), others of the solid marble pattern. Nearly all of 
the latter were split open by the discharges, while of the former 
none was damaged in the slightest degree. One of the line 
arresters was provided with three connections to one feeder, with 
a spark gap and tell-tale paper in each discharge circuit. This 
arrangement is shown in Fig. 84. The connections to the feeder 
were made about two feet apart. After thunder storms each 
tell-tale paper was found to be perforated, but whether the dis- 
charges occurred simultaneously or successively is not known. 
The perforations shown in Fig. 35, were taken from this arrester. 

This non-arcing railway lightning arrester is eminently suited 
for the protection of direct current circuits up to 1,000 volts. 
On 1,000-volt alternating current circuits from' smooth body 
armatures it also operates satisfactorily, but on similar circuits 
from toothed body armatures, the arresters break down after a 
few discharges, and a short-circuit is established. However, it 
is not impossible that two or three of these arresters might not be 
used to good advantage in series, on circuits of high potential. 

The especial advantages of this arrester may now be summed 
up as follows : 

1. It offers a direct and non-inductive path to earth. 

2. It is absolutely non-arcing and consequently requires no 
attention after being once properly installed. 

3. It has no moving part* and there is nothing about it to get 
out of order. 

4. It is small, and therefore easily installed under a car. 

5. It is cheap, and can therefore be used in large numbers on 
the line, on the cars, and in the station. 

6. Its non-arcing property avoids danger from lire, which prop- 
erty also ensures the non-interruption of the system due to 
blowing of fuses and constant throwing of the circuit-breakers. 

7. Its simplicity and reliability will commend it to every one. 
In my closing remarks I wish to answer the now old and oft 

repeated question " How many, and what kind of arresters would 
you advise us to use on our line ? " as follows : The proper num- 
ber of line arresters, is that number which will prevent discharges 


from entering the station. Station arresters, if used at all, 
should be installed ^vith the one idea of providing a final oppor- 
tunity for discharge, but as the tendency to discharge occurs on 
the line, often several miles away from the station, a sufiicient 
opportunity should be provided there where the tendency to dis- 
charge originates, and in this manner advantage may be taken of 
the large inductive resistance afforded by the circuits leading 
back to the station. If discharges enter the station it is a sure 
indication that they have done so for lack of sufficient opportu- 
nity to discharge from the line — for lack of a suflScient number 
of line arresters. 

It is well to protect dynamos with lightning arresters — ^it is 
better to avoid the necessity of this protection by discharging the 

It is even well to use a lightning arrester having a circuit 
interrupting attachment. It is better to avoid the necessity of a 
circuit interrupting attachment by using a non-arcing arrester. 
In fact — 

An ounce of prevention is always 
Better than a pound of cure. 


Discussion in Philadelphia. 

Mr. Joseph Sachs : — Mr. President, I would like to ask Mr. 
Wurts if he has ever tried the choke coils without the arresters 
upon the comparatively low potential circuits in Colorado ; and 
wnether the action upon a low potential circuit would not have 
been just the same as the proposed action on a high potential — 
that is, leaving out the arresters altogether and only using choke 
coils on the line. 

Mr. Wurts: — I have not made any such experiments, but 
should expect to find the action of these coils the same on a low 
potential system as on a high potential system. On a low poten- 
tial circuit, however, the insulation of the apparatus being in- 
ferior to that found on a high potential circuit, it is possible that 
a system of choke coils might not sufficiently protect the arma- 
tures and other translating devices from the electric strains, which 
would be set up by the siirgings. In other words, it is expected 
that witli very high potential systems, such as are now being 
talked of in connection with long distance transmission, the surg- 
ings may be broken up and rendered harmless to the very higli 
grade of insulation which would be used in such systems. On 
the other hand, with low potential systems, it might be that the 
number of choke coils found necessary for efficient protection 
would be prohibitive. This system of protection seems to be 
more particularly adapted to long distance power transmission 
circuits, where there are no translating devices intervening be- 
tween the extremities of the system. Ileferring to my tests with 
a combination of choke coils and spark gap discharge circuits, i^ 
is interesting to compare the results which I obtained in Tellu- 
ride and in Denver. In Telluride I used four choke coils with 
most satisfactory results. In Denver I used two coils, and found 
that these did not altogether protect lightning arresters which 
were connected nearer the dynamo, and thcpe results, obtained in 
Denver with two choke coils, were verified by the results ob- 
tained in Telluride with four choke coils, inasnmcli as with the 
four coils in series, some of the discharges reached the third and 
fourth discharge circuits; that is, passed beyond the first, second 
and third coils. » 

Mr. Sachs: — It would seem to me, that if we had enough 
choke coils in the line, the effect of the disruptive discharge 
could be chop]3ed down so low that it would not do any harm to 
the insulation of the machine at all, and that there would not be 
potential enough to jump any gaps. As I understand tlie theory 
of the use of the choke coil used here, it simply acts as a buffer 
against the discharge. The discharge comes along and strikes 
the buffer ; part of it passes on, and the part that passes on is 
very much less than that which initially struck the buffer, and 
so on until you get practically a very small amount. Now, if 
you went on far enough and liad choke coils enough, you would 


get down to an amonnt that would not hurt your armature at 
all. You would get down to ptactieally nothing, and in a caae 
like that, you would not need any spark gap whatsoever. But 
another question arises : the use of these various inductances in 
the line upon a system of alternating currents would, in my 
mind, have some effect, perhaps ^fery small, upon the line, and 
the question I think to be decided would be, what the relation 
would be between the point where you got no discharge, by 
putting in enough choke coils, and the effect upon the impedance 
of the line. 

Me. Wuets: — I have not tested in practice this system of pro- 
tection against lightning discha^es, but am hopeful that such a 
system will prove successful. In regard to the self-induction of 
these choke coils, I do not think that they will interfere seriously 
with the operation of an alternating current system at 7,200, or 
even at 16,000 alternations per minute, because no iron core is 
used and the number of turns is small. Referring to my paper, 
it will be noticed that I employ only seventeen turns. 

Mr. Sachs: — The point, however, would be, if the 17 turns 
were multiplied by the number of choke coils, you would have 
that many more turns, that is, if you put in enough choke coils 
to kill your discharge entirely, l^our 17 turns might increase to 
five, six, seven and eight, etc., times 17. In reference to the 
iron, it would appear to me that if the iron core could be lami- 
nated and insulated to a very fine point so that the induced cur- 
rents in this secondary were brought down to a very small 
current, that your iron would really help along the impedance of 
the choke coil. The actual results that you obtain now, would 
appear to me inferior, because the iron is not sufficiently lami- 
nated and insulated, and the currents set up in the iron bring 
down the induction in your primary, and, therefore the result is 
not as good as witliout tlie iron. If, however, your iron wires 
could be made sufliciently small, and insulated so that the cur- 
rent induced therein would be infinitesimal, why, then, I should 
think that the iron would actually help you. It may be, how- 
ever, that this cannot be practically attained on account of the 
very high potential induced in the core, and the necessity, there- 
fore, of extremely small and well insulated wires. 

Mr. Wm. Stanley : — I have been greatly interested in this 
paper, particularly because of the logical demonstration that Mr. 
Wurts has given us. It seems as though the paper were one 
continuous line of logical reasoning from one end to the other. 
It seems to me that he has shown to us more new and interesir 
ing experimentd with lightning discharges than we have ever 
known before. The suoject of lightmng discharges must be 
viewed from the lightning discharge standpoint. In working 
with lightning discharges we are not using alternating currents 
tliat we know very much about. We are familiar with currents 
of, perhaps, 75 periods, or something of that sort, but the light- 


ning discharge currents are of enormous frequency. Of course 
it is true that Mrith the ordinary frequency the self-induction of 
the coil^would be increased by winding on it additional turns of 
wire, or by adding to it an iron core, ^ut if the frequency be in- 
creased id or 50 or 100 times, the iron core may be considered as 
consisting of iron wires 10, 50, or 100 times larger. In other 
words, the local currents in these iron wires are 10, 50, or 100 times 
more important, and the self-induction of the coil may be largely 
impaired by the foucault series. It seems to me, however, that 
Mr. Wurts might have given us a little clearer statement regard- 
ing the discriminating properties of the apparatus on page 341. 
It is a charming diagram to me, for the arrangement snows that 
each one of these by-paths is tuned to a particular rate of alter- 
nation ; that if the lightning discharge oe surging on the line, 
the first by-path will be tuned by ite spark gap, self-induction 
and capacity, to one frequency o^ the discharge, the second to 
another frequency, the third to another frequency; and, so it 
seems to me, Mr. Wurts takes through each one of these by- 

?ath spark gaps, a certain amount of the discharge current, 
'hat is to say, he takes the surging current and splits it up into 
a number of different frequency currents, and then carries each 
of them off to the ground in its particular path, if I correctly 
understand the diagram. 

The self-induction induced into the line by the choke coil 
practically amounts to nothing. I have not calculated it, but I 
should imagine it would be on the coil shown, perhaps, a couple 
of volts witli 50 or 60 amperes of current passing or something 
of that sort, with the ordinary frequency of 72 periods, and the 
self-inductive k. m. f. with a liigh potential system of three or 
four thousand volts would amount to nothing at all. 

Another point that interested me particularly was the diagram 
at paffe 355. I do not think that the straight lines drawn on 
that aiagram, are a fair exposition of Mr. Wurts' work, for they 
seem to show that one could wind a choke coil, adding turns to 
it and increase the self-induction of the coil up to a certain point, 
and then that the self-induction could not be farther increased 
by adding more current. Now the dotted lines on that diagram 
sfiow that that is not so. It shows that that knee at the top of 
the angle is really a curve, and that really there is an increase of 
self-induction by adding more turns. Is not that so i 

Mr. Wurts : — I think it is to a slight extent. 

Mr. Stanlf.y : — If a straight line is a correct demonstration of 
the results, then we have a saturation for air. If the curved 
line is the correct demonstration, then we have, I think, the ordi- 
nary results found before. I would like to ask Mr. Wurts one 
?uestion. In 1S85 or 1886 I built an alternating line, and found 
had to protect it from lightning ; so instead of putting my 
wires underground, I put my ground over my wires, and strung 
a ground above my line, grounding it every pole or two ; and ob- 


tained very satisfactory results. We had no trouble whatever. 
Now, is it not true that in this part of the country, leaving out 
of consideration Colorado and nigh altitudes, is it*^ not true that 
very excellent results in line nrotection may be obtained by sim- 
ply striuging a wire above the line, and so forming a belt of 
earth potential above the wire without any further apparatus. 

Mb. Wurts : — I cannot say that I have had any considerable 
experience witli the use of overhead ground wires as a means of * 
protecting aerial lines against lightning. I am, however, familiar 
with the results obtained in two places ; one on Staten Island, 
where the overhead ground wire has been used successfully ; the 
other at Telluride, \diere it has proved a total failure. Upon 
making inquries at the Staten Island plant, I learned that prev- 
ious to the use of the overhead ground wire, diBcharges entered 
the station frequently and with violence, but that after the over- 
head wire had been erected, although the discharges continued 
to enter the station, they were less frequent and much less 
violent. In Telluride the overhead ground wire failed; the 
reason may possibly be this: If the wires become charged, as I 
am inclined to believe they do, by contact with the surrounding 
charged atmosphere, and if the wind be blowing across the length 
of the wires, then both wires will tend to drain the atmosphere 
of its charge, but the drained portion of the atmosphere belong- 
ing to each wire will have a cross- section in the shape of a wedge, 
the direction of the wedge being that of the wind and more or 
less horizontal, so that tne drained portion of the atmosphere 
caused by the overhead ground wire will fail to include the elec- 
tric wire. If a charged atmosphere be kept rapidly moving over 
a well-insulated electric wire, it is probable that the charging 
from the atmosphere will exceed the loss due to leakage. 

Mr. Charles Hewitt : — Some years ago the Edison companies 
made experiments with overhead grounded wires, using them as 
guard wires. They were put up primarily as guard wires, but 
the intention afterwards became to use them also as lightning 
protectors, and a certain gentleman took out a patent, using a 
barbed wire, similar to barbed fence wire, in the hope, I suppose, 
that the points of the barbs would pick the current out of the 
air and carry it off. Mr. W. J. Jenks has given a good deal of 
study, I think, to that very question. I hope he will say some- 
thing before the discussion closes. I would like to ask Mr. 
Wurts, however, whether it is necessary to connect a lightning 
arrester to each one of these coils on page 341. What would be 
the effect of connecting, to say one arrester, connecting one ar- 
rester between each coil i We have here in Philadelphia, on 
the traction company's plant, not only the question of protect- 
ing generators, but the question of protecting a great many 
mues of valuable lead caWe, which is quite as important, if not 
more important than the question of generators, and the problem 
is simply this : We have miles of lead cable coming out of the 


ffroand, say, at one or two points. On one traction company's 
fine we have a cable coming out at foar points, but that is un- 
usual. Most of the cables come out at two points. As I under- 
stand the problem from Mr. Wurts' paper, we must get the 
lightning arresters between the trolley ana that cable if we want 
to protect it. I may be mistaken about this. It may be we can 
place our lightning arresters on the poles along the trolley line 
and in that way avoid these nodal points ; but it seems to me 
that it will be necessary for us to get our fightning arresters in 
between the cable and the trolley wire. In that case we would 
need four coils and four lightning arresters on one pole, and on 
an iron pole it would be quite unsightly and a rather difficult 
thing to put up, as we haven't much space. 

Mr. W ukts : — I think the gentleman has correctly understood 
my ideas in this matter. If the system of protection, illustrated 
in Fig. 3, is to be used, the spark gaps and choke coils must be 
connected between the trolley and the underground cable. Ordi- 
narily, and with a reasonably high grade of insulation, I believe 
that electric systems can be protected by a liberal distribution 
of line arresters ; that is, a large number of opportunities for 
discharge should be provided, so many, in fact, that the few 
opportunities for disciiarge afforded by the translating devices 
shall be small, in comparison with the number provided by the 
lightning arresters, it is, however, well known that under- 
ground cables are particularly sensitive to the electrical snrgings 
set up during thunder storms, and that they are liable to be 
punctured, so that where cables are to be protected, I unhesitat- 
ingly recommend the use of four choke coils in series between 
the overhead and underground system, toother with four light- 
ning arresters, connected as shown in Fig. 3. My experiences 
in Telluride and in Denver have led me to believe that a fewer 
number of coils would be insufficient. For the proper protec- 
tion of cables it may even be possible that live or six coils will 
b,e found necessary ; for it must be borne in mind that the insu- 
lation which I protected in Telluride was of a very high grade, 
much holier than is ordinarily found in underground cables. 

Mb. IIewitt: — ^What would be the effect of connecting the 
one arrester if Has it ever been tried? Or what would you sup- 
pose would be the effect? 

Mr. Wurts : — I think the result would be that the discharges 
would frequently enter the dynamo armature. In Telluride I 
had four choke coils in series, together with four opportunities 
for discharge, as indicated in Fig. 8, and as the majority of dis- 
charges passed across the second discharge circuit, it is reasonable 
to think that if there had been only one discharge circuit, many 
of the discharges would have reached the generator. 

Mr. Hewiti' : — Don't you give four opportunities ? You have 
four coils. 

Mr. Wurts: — Yes; I provided four opportunities for dis- 


charge, but I understand your question to be: What would 
happen if only one opportunity were provided. 

Mb. Hewitt : — ^What I mean is, if there were four coils and 
those coils were connected to one arrester, what would be the 
effects Wouldn't you practically get four opportunities^ 

Mb. Wtjbts: — That arrangement would provide only one 
opportunity, and would at the same time short-circuit the choke 

Mb. Sachs : — I would like to ask Mr. Wurts another question 
with reference to the iron wires. I would like to ask whether 
he tried various sizes of iron wires, and whether the iron wires 
were in intimate contact or insulated. I think these features 
make quite a difference. From what I could see of the wires, 
they seemed to be of rather a fair size and not insulated from 
one another. In reference to the idea proposed by Mr. Hewitt, 
it would appear to me that if you had choke coils enough to 
tone down the potential of the lightning discharge sufficiently, 
one fi:ap between the machine and the first coil would take care 
of all tlie lightning that would be left. 

Mb. Habbington : — Gaps are cheaper than choke coils, and it 
has been my practice, covering the last four years, to use a large 
number of gaps placed at many intervals on the line. In fact I 
place them at every tap of the feeders to the trolley wires and 
use the ordinary spark space with a fuse wire in series with it. I 
never had any trouble at all from burn-outs at the station using 
this method. 

Mb. Wubts : — Referring to the matter of introducing an iron 
core into these choke coils, the e. m. f. per foot of wire in the 
coil is so high, that no matter how finely sub-divided the iron 
may be, discharges will take place between the iron particles, 
unless, of course, these be thoroughly insulated from each other. 
The bundle of iron wires I have used as a core, is not made of 
very fine wire, but has served to illustrate what I wished to 
show; namely, tliat secondary currents are set up, and that 
these secondary currents cause the coil to offer less resistance to 
the passage of disruptive discharges. Dr. Lodge has shown con- 
clusively, I think, that the mere presence of iron in a coil does 
not at all affect the resistance of that coil to the passage of dis- 
ruptive discharges. Ilis experiments were made oy using a very 
finely sub-divided iron core boiled in paraffin. 

M!b. a. E. Kennelly : — There are so many points of interest 
in this paper that one can scarcely do justice to it on first peru- 
sal. But some information Mr. W urts might give us upon those 
points would, I think, have important bearing upon their appli- 
eation. For example, on pages 354 and 355, Mr. Wurts alludes 
to experiments made in the laboratory, with such choke coils a& 
those now before us, and where he is experimenting upon the 
number of turns that are desirable to produce the oest effect, 
and he says he has found by experiment that the impedance does 

884 WURT8 ON LIQUTNINQ ARliE8TEB8. [May 16^ 

not continuously increase with the number of tums. Diagrams 
are then riven on page 355 to supplement that view. The 
method of testing is a very ingenious and a very pretty one. 
But I think he means impedance there, in the practical sense of 
what takes place in that particular circuit under the particular con- 
ditions, and he does not mean that the impedance of the coil as 
actually represented in ohms did not continuously increase. I 
think there is no question that the impedance, as measured in 
ohms of such a flat coil, would very continuously and very 
markedly rise, as the number of turns was continuously increased 
upon the outer edge ; but the experiments seem to show con- 
clusively that the practical impedance, or that the effect of 
arresting the discharge through them, did not appreciably in- 
crease with the electrical impedance of the coil beyond a certain 
point ; that is to say, the sparks approached a certain ultimate 
rate by an approximately straight line. Of course, we might 
expect that if the conditions of the experiment had been varied, 
if the Leyden jar had been altered in size, or if the resistance 
or inductance of the path from the Leyden jar had