140 
MR. R. I). STEELE OX THE MEASUREMENT OF IONIC VELOCITIE 
Since the molecular conductivity /x = , we net 
' n 
~ [(tt + f) — a {v — f')] 
/A _ n LV / ^ 
h + r) — u^{v — r')] 
'h 
At infinite dilution c — n and a = 0, 
IM x[(tt + r) - « (r — U)] 
and ^ = - 
r — v' 
— X — ax - , 
u + f 
/^ , A’ “ 
or X = — -4- ax -. 
n + V 
Hence, only in the case that v = v' or a = 0 do we obtain the true coefficient of 
ionization from the conductivities. 
Further, from the conductivities and transport number we are not able to 
determine the values of the specific ionic velocity for any one species of ion, unless 
the transpoi't number is determined at such a dilution that no coinplexes exist. With 
other values of p we obtain instead 
U = XU — axv'(m — I) 
and y = XV + ax {mv' — v), 
and therefore the apparent velocity of the anion becomes increased and that of the 
cation decreased by increasing concentration, and consecpient increase in a. To 
determine the specific ionic velocities, therefore, of .such cations as Ba, Ca, Cu, &c., it 
is necessary to know the value of p at very great dilutions, much greater than any at 
which this important physical constant has been hitherto determined. 
It is of interest to point out that the values for p recently determined by Noyes 
for 0'02 N solution of barium chloride and nitrate are such as give to Ba the same 
absolute velocity in solutions of the two salts 
p-cc V X (I — p) for BaCL = U'000564 
for BaNOg = U’0005G2. 
Since the total amount of current crossino- unit area of the conductino- medium in 
unit time under a potential fall of tt volts per centim. = e7Tc[{iL + t') — a (r — r')], 
the amount of current passing across a section of area A in a solution of concentra¬ 
tion N is o’iven hv 
(J = Aerrx r) — a (r — r")] N, 
since 
