MR. W. C. D. WHETHAM ON IONIC VELOCITIES. 
349 
Current reversed at 4.0 downwards. 
Galvauometei'. 
Time. 1 
74-9 
6.25 
20-9 1 
27-2 1 
72-8 
11.30 
27-2 
12.45 
29-2^ 
1.30 
30-5 ^ 
1.45 
30-9 J 
Position. 
I'45 ceiitims. pev Lour. 
, a. G5 centims. per Lour. 
■j 
Current upwards. 
— 
Galvanometer. 
Time. 
Position. 
73-9 
2.0 
30-9 5 
4.15 
>-P53 centims. per hour. 
73-0 
5.0 
26-3 y 
1-43 
7.15 
23-0 j 
. J 
Means going up G. = 73°‘9 r = 1‘57 centims. per hour. 
down 
73°'9 
1-60 
Means oh all observations G. = 73“‘9 
V = 1*59 centims. per hour. 
We get y from the table of graduations to be and find from our equation 
(p. 346) 
rA 1-59 X -430 x 255 
- -77i-7h X 10 
yr lo7 X X 60 X 60 
-li 
This is for unit potential gradient on the C.G.S. system, and gives for a gradient 
of 1 volt per centim. a velocity of 
3’09 X 10~^ = 0’000309 centim. per second. 
This is the velocity of the copper ion in a solution of 0‘1 grm. equivalent per litre, 
while Kohlrausch deduced for infinite dilution 
0*00031 centim. per second. 
The next case I shall describe is that of a pair of salts whose 0*1 grm. equivalent 
solutions have specific resistances which are nearly the same. Mr. Fitzpatrick 
kindly supplied me with a long list of conductivities reduced to comparable units. 
