MR. W. C. D. WHETHAM ON THE VELOCITIES OF THE IONS. 511 
The solutions were then placed in the velocity apparatus, and measurements taken, 
the temperature of the water bath being 15°°8. 



Time. Galvanometer. | Scale reading, | Displacement in 
° 10 minutes. 
11.14 35°8 24°39 
16 i. 24-98 
18 é 24:20 
11.24 35:9 23°93 0:46 
26 3 23°83 0°45 
98 x 23°75 0-45 
11.34 36°0 23°50 0.43 
36 a 23°40 0-43 
38 ‘ 23-30 0-45 
11.44 | 36:0 23-05 0-45 
46 ie 29-95 0-45 
48 2 29-86 0-44 
11.54 36:0 22-60 0°45 
56 | i 22°51 0:44 
58 | a 22°41 0°45 
12. 4 36°2 22°16 0:44 
6 < 29-05 0-46 
8 | 50 21:98 0:43 
12.14 | 36:3 21:71 0°45 
18 a 21°52 0:46 





The velocity of the junction thus kept constant throughout. Its mean value is 
0°446 centim. in 10’, The mean galvanometer reading is 36:0, which indicates a 
current equal to that produced by the electromotive force of one Daniell (= 1:08 
volt) working through a resistance of 121 + 10 = 131 ohms. The area of cross 
section of the tube is 0°430 square centim., and 7 is the reciprocal of 9°60 X 107%. 
We thus get 
 _ vA _ 0-446 x 0-430 x 131 x 9-60 x 1078 
poe gp om 10 x 60 x 1-08 

0°000372 centim. per second. 
Experiments presently to be described gave for the temperature coefficient of the 
velocity the values 2°78 per cent. at 15°°7, and 2°05 per cent. at 12°°8. The mean of 
these 274 is very near the value, 2°5, found for the temperature coefficient of the 
conductivity, and justifies us in using the latter value for the small correction 
necessary to reduce the observations to 18°, the temperature for which KoHLRAUSCH’s 
numbers are calculated. 
