Chemical Affinity in terms of Electromotive Force. 343 



number of groups corresponding to equal intervals of time 

 (3 or 5 minutes), the average readings for each interval being 

 again averaged to give the mean reading for the whole period ; 

 so that for an hour's observation more than 120 total readings 

 were taken. 



49. In this way the following numbers were obtained, the 

 amounts of gas collected being translated into C.G.S. current- 

 units by the formula 



c _ Vx 0-0005363 _ V Q . 094 g 

 °~ T x 60 x 8-98 x 0-000105 ~ T X U UJ J ' 



where C is the C.G.S. current, V the volume of gas (dry, at 

 0° and 760 millims.), T the time in minutes, and 0-0005363 

 the weight in grammes of a cubic centim. of mixed gases at 0° 



y 

 and 760 (§ 39); i. e. where _ is the volume of gas evolved 



per minute. The resistance of the wire is calculated from 



Ohm's law ( C= p, whence R= p ) by dividing the average 



potential difference by the current. Every experiment was 

 made as nearly as possible in the same way, so as to diminish 

 sources of error and make the results comparable, the only 

 noteworthy difference being that with the stronger currents 

 shorter times were given, and the beaker of water in which the 

 wire was immersed was slightly cooled at intervals during the 

 experiment to avoid the temperature rising too high and having 

 too wide a range. 



No. of 

 cells in 

 battery. 



Time in 

 minutes. 



Gas evolved 

 in cub. 



cent., dry 

 at 0° and 

 760 mm. 



Average 

 G.C.S. 

 current. 



Temperature of water. 



Average 

 potential- 

 difference 

 in C.G.S. 

 units. 



Resistance 



in C.G.S. 



units. 



Initial. 



Final. 



Average. 



3 

 3 



4 



6 



9 

 9 



12 

 12 



60 



60 



30 



30 



30 

 20 



20 

 20 



256-6 

 234-5 



Average 



244-3 



461-7 



777-9 

 493-4 



Average 



624-7 

 638-6 



Average 



0-0406 

 00371 



8-5 

 7-5 



7-9 



7-4 



7-2 

 7-4 



7-1 

 7-6 



100 



9-5 



9-2 

 9-0 



110 



9-7 



101 



10-8 



9-24 

 8-36 



880 



8-50 



8-20 



9-16 



8-58 



8-87 



8-64 

 9-18 



8-91 



0-4655 X10 8 

 0-4275 „ 



0-8931 „ 



1-697 „ 



2-881 „ 

 2-732 „ 



1-147 XlO 9 

 1-152 „ 



003885 



1-1495 „ 

 1-157 



0-0772 



0-1459 



0-2458 

 0-2339 



0-2398 



1-163 „ 



1-171 „ 

 1-168 „ 



11695 „ 



1-172 „ 

 1-172 „ 



1-172 „ 



3-469 „ 

 3-549 „ 



0-2961 

 0-3027 



0-2994 





