580 REPORT— 1897. 



tion near the platinum. An E.M.F. of 0-60 of a volt, and on short circuit 

 0-90 ampere, were obtained. Tiie current remained fairly steady. The surface 

 of each electrode was about forty-five square inches. 



A cell made up as above, but with graphite instead of carbon, gave 0'64 of a 

 volt, but dropped rapidly on short circuit, the graphite not oxidising fast enough 

 to give a steady current. 



A dense carbon rod opposed to powdered carbon gave 0-40 of a volt, and on 

 short circuit 0'20 of an ampere. The rod was encased in filter paper to protect it 

 from floating particles of powdered carbon, and the chlorine passed into the 

 solution near it. 



Two small glass beakers with a carbon rod iu one and a platinum plate in 

 the other, and containing hydrochloric acid, were connected by an inverted U tube. 

 When chlorine was passed into the vessel with the platinum, an E.M.F. of 

 0*48 volt was obtained. When chlorine was passed into the beaker containing 

 the carbon rod, an E.M.F. of 0-14 was obtained, but it dropped almost immedi- 

 ately to zero. When chlorine was passed into both beakers, no E.M.F. was 

 obtained. 



The chemical reaction of the chlorine-carbon cell was as follows : 



H^O + CI , = 2nci + 0, 



the oxygen of the decomposed water attacking the carbon, and hydrochloric acid 

 and carbon dioxide being formed. 



Carbon Monoxide-Chlorine Cell. 



Cell made as follows : a glass tube, 2'25-inch bore and G inches long, corked 

 at each end, with a porous tube, 1 inch outside diameter, passing through the 

 glass tube and corks, and corked at each end ; carbon rods and gas inlet and outlet 

 tubes let into each chamber, which were filled with dry animal charcoal previously 

 treated with hydrochloric acid. The porous tube was saturated with concentrated 

 hydrochloric acid. Chlorine gas was passed through the outer tube. An E.M.F. 

 ot 0'18 volt was obtained. When carbon monoxide gas was passed through the 

 inner tube the voltage increased to 0'33 volt. A slight increase of the pressure 

 of the gases increased the voltage. The glass tube became hot. This reaction 

 would produce carbon oxychloride. 



Marsh Gas- Chlorine \Cell. 



Two carbon tube electrodes, three-fourths of an inch in diameter and four inches 

 long, opposed to one another in a solution of hydrochloric acid, with chlorine 

 passed into one and marsh gas into the other, gave an E.M.F. between 0-60 and 

 070 volt, varying with the condition of the carbon. A current of 0-70 ampere 

 was obtained on short circuit, but the cell rapidly polarised. Afterwards fresh 

 carbon electrodes, with the gases passing through them, were placed in distilled 

 water, and the E.M.F. gradually increased from 000 to 0-14 in twelve hours. 

 On testing the solution hydrochloric acid and carbon dioxide were found to be 

 present. The chemical reaction of this cell is as follows : 



CII4 + 4CI2 + 2H2O = CO, + 8HC1. 



The calculated E.M.F. of this cell is 0-65 volt. 



In these experiments it will be noted that platinum is not essential to the 

 reactions. _ Both electrodes iu each case can be carbon tubes or plates. 



In making these determinations of electromotive force and current, a West-on 

 direct-reading voltmeter and mil-ammeter were used. Resistance of voltmeter, 

 352 ohms, reading from 0-01 to 3-00 volts. The ammeter read from Q-Ol to 

 2'00 amperes. 



