Thomas A. Edison designed a variation of the 

 Lalande-Chaperon cell in 1889,''- but later he invented 

 another form of alkaline accumulator (fig. 34). 

 Nickel-plated steel electrodes were covered with nickel 

 peroxide and graphite to form the anode, and with 

 finely divided iron and graphite to form the cathode. 

 The electrolyte was again a solution of caustic potash. 

 The very high currents that could be drawn by the 

 Edison cell made it practical for use in electric trac- 

 tion. In Edison's cell — a form of which is still used — 

 the voltage was about 1.3 volts, and the current was 

 even higher than that of the Lalande-Chaperon cell. 



The dry cell began with the 1868 cell of Georges 

 Leclanche,*' which used a solid depolarizer (figs. 33, 

 35). In the Leclanche cell, a carbon electrode was 

 inserted into a pasty mixture of manganese dioxide 

 and other materials. A zinc electrode in a sal am- 

 nionic solution was separated from this mixture by a 

 ceramic cylinder. This cell gave 1.5 volts, but its 

 pasty texture and its high internal resistance limited 

 it to intermittent use, and its current strengths were 

 not too high. However, it was used extensively in the 

 19th century for telegraph and telephone lines and for 

 other signaling systems. The ancestor of the modern 

 dry cell was C. Gassner's modification" (fig. 36) of the 

 Leclanche cell. The electrical characteristics and 

 uses of the Gassner cell were similar to those of the 

 Leclanche cell. A paste of zinc oxide, sal ammoniac, 

 plaster, and zinc chloride formed the electrolyte; and 

 the zinc electrode formed the container. Commercial 

 production of such dry cells began about 1890. 



After the middle of the 19th century, standardiza- 

 tion of voltages became an increasingly important and, 

 at the same time, difficult problem. At first the 

 Daniell cell was used to provide a reference voltage, 

 but in 1873 J. Latimer Clark ^^ devised an even more 



«U.S. Patent 430279, June 15, 1889; A. E. Kennelly, 

 "The New Edison Storage Battery," Electrical World, 1901, 

 vol. 37, pp. 867-869. 



*' Georges Leclanche, "Pile au peroxyde de manganese a 

 seul liquide," Les Mondes, 1868, vol. 16, pp. 532-535. 



" German Patent 45251, 1887. See also, "Gassner's Dry 

 Battery" in Eleclriciati, 1888, vol. 21, pp. 245-246, 703-704; 



1889, vol. 24, p. 185; 1890, vol. 25, p. 508; 1892, vol. 28, pp. 

 643-644; and Heinrich Krehbiel, "Vergleichende Unter- 

 suchung von Trockenelementen," Elektrotechnische ^eitschrift, 



1890, vol. 11, pp. 422-427. 



*' J. Latimer Clark, "On a Voltaic Standard of Electromotive 

 Force," Proceedings oj the Royal Society of London, 1872, vol. 20, 

 pp. 444-448; "On a Standard Voltaic Battery," Philosophical 

 Transactions, 1874, vol. 164, pp. 1-14; Lord Rayleigh and Mrs. 

 Sidgwick, "On the Electro-Chemical Equivalent of Silver and 



Figure 23. — Smee cell. From F. C Bakewell, 

 Manual of Electricity, London and Glasgow, 

 1859, P- 147- 



stable cell (fig. 37). The potential of the Clark cell 

 was reproducible to an accuracy of one-tenth of 1 per- 

 cent, and its use slowly spread. However, by the turn 

 of the century the Clark cell began to be supplanted 

 by E. Weston's standard cell,*^ which finally replaced 



on the Absolute Electro-Magnetic Force of Clark Cells,'' 

 Philosophical Transactions, 1884, vol. 175, pp. 411-460. 

 « U.S. Patent 494827, April 4, 1893. 



PAPER 28: DEVELOPMENT OF ELECTRICAL TECHNOLOGY IN THE 19TH CENTURY! I 

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