MR. W. C. D. WHETHAj\r ON IONIC VELOCITIES. 
357 
(After this, the velocity began to fall off, and the kathode solution (CaClg) got thick 
and faintly blue, perhaps indicating that some current is conveyed by the water 
of crystallisation of the C 0 CI 36 H 2 O, which deposits a hydrate when it meets the 
calcium, and that some cobalt goes faster than the rest and colours the solution. 
Finally, the junction went the wrong way, and other secondary actions occurred. All 
this shows that the effect of too great concentration has not yet been eliminated.) 
Taking the mean velocity while it remained constant we get G = 46°’8, v = 0'25 
centim. per hour. 
Therefore v-^ = vAjyr = 0’000022 centim. per second. 
Adding this to the velocity of the chlorine (viz., 0‘000026) we get 
V = u V = 0*000048 centim. per second. 
The conductivity is 2*86 X 10“^^, and on Kohlrausch’s theory this gives 
V = 10352^ = 0*000060 centim. per second. 
Considering the difficulties of the method and the effect of too great concentration, 
these numbers must be considered to agree within the limits of experimental error. 
The conductivity of the nitrate of cobalt is rather greater than that of the chloride. 
This means that the number of active molecules is larger, and that the salt more 
nearly approaches the normal state. We should therefore expect the agreement to 
be closer than in the case of the chloride. 
The velocity of the cobalt was found by using cobalt and calcium nitrate solutions, 
the first being red, the second colourless. 
Upward velocity—Means : G = 50°*3 v = 0*44. 
Downward ,, ,, G = 43°*6 v = 0*41. 
Means of both directions : G = 46”*9 v = 0*43. 
No irregularities (such as reversals, &c.) were detected with these salts. This is 
what would be expected from the better conductivity. 
The result is 
= vAjyr = 0*000044 centim. per second. 
The velocity of the NO 3 group can be calculated from the numbers in p. 356. The 
conductivity is 3*80 X 10“^^, and this gives 
Therefore 
~ 0*000035 centim. per second. 
V = u -f- n = 0*000079 centim, per second. 
