. Bulletin. Science. 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 volts, and the current was e
. Bulletin. Science. 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 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 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. « Patent 430279, June 15, 1889; A. E. Kennelly, "The New Edison
Size: 1140px × 2191px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorunitedstatesdepto, bookcentury1900, booksubjectscience
