. Bulletin. slower, and afterfive hours it appears asan asymptote to the xaxis, when the currentis seen to be not eco-nomically used. The effect of the in-creased rates of flow isshown in figure 7. In the experimenthere represented therate of flow was in-creased to 120 litersper hour (velocity, 42inches per minutethrough cathodes), ordouble that employedin obtaining the resultsshown in figure 6; otherconditions were thesame as in figure 6. Itwill be noticed that thesilver was much morerapidly precipitatedthan in the previousexperiment. The voltage in this experiment varied between andolts.
. Bulletin. slower, and afterfive hours it appears asan asymptote to the xaxis, when the currentis seen to be not eco-nomically used. The effect of the in-creased rates of flow isshown in figure 7. In the experimenthere represented therate of flow was in-creased to 120 litersper hour (velocity, 42inches per minutethrough cathodes), ordouble that employedin obtaining the resultsshown in figure 6; otherconditions were thesame as in figure 6. Itwill be noticed that thesilver was much morerapidly precipitatedthan in the previousexperiment. The voltage in this experiment varied between andolts. In spite of the high current density, there was no gas visi-ble on either cathodes or anodes, so long as the solution was in circu-lation. Fiimre 8 shows the results of an experiment similar to that repre-sented in figure 7. except that the area of cathodes was old cathodes of 30-mesh iron wire and two new cathodes,each consisting of 10 sheets of 1-mm. wire cloth, were used. The effec-. 3HOURS Figure 7.—Electrodeposition results with silver solution•with rate of flow of 120 liters per hour; velocity,about 19 inches per minute through open hox, 4|inches through cathodes; anodes and cathodes sameas in figure 6. Voltage varied. PRELIMINARY EXPERIMENTS. 55 tive surface area of the cathodes was approximately square feet,or twice that of the cathodes used for the previous test. In this ex-periment the voltage was controlled better than before. In the be-ginning volts was employed, but after two and one-quarter hoursthe potential was raised to volts, remaining thus until fiveand one-quarter hours had passed. At the end of the five and one-quarter hours anew charge of 21KAgCy2 was add- 20ed, bringing the 19 18 16 15 it 13 12 10 I per cent K Cy, pei; cen per cent . n £• nig. per 00 e. c.,4. 39 on ices per ton volts £ mg., nine JS 0 2 \ \& • , 1\ 150 rnpe rolts •es; 0 3 % Vs \ 7 a 13 Y
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