ON ELECTROLYSIS. 76 
List oF SUGGESTIONS. 
It seems permissible and convenient to print here the list of suggestions. 
issued, soon after the meeting, to the Committee appointed jointly by 
sections A and B, ‘for the purpose of considering the subject of Electro- 
lysis in its Physical and Chemical bearings,’ in case they might aid any 
member in deciding on a special subject of investigation. 
Some of the statements have been slightly amended ; Nos. 1] and 12 
have been added. 
1. Is Ohm’s law exactly true for Electrolytes ? 
We know that it is roughly true for many electrolytes within certain 
rather wide limits of possible experimental error, but its exact verification 
for any one electrolyte has not yet been attempted, and it is very important. 
The question is whether, eliminating all effects due to rise of temperature, 
the resistance-coefficient of an electrolyte is absolutely constant for 
infinitesimal, ordinary, and powerful currents. 
There are two or three plausible ways in which a discrepancy from the 
exact law may be expected to arise. 
(a) Supposing the ions absolutely dissociated and to make their way 
through the liquid according to customary laws of fluid friction, propelled 
as it were by the electric forces, as is assumed in the theories of Wiede- 
mann, Quincke, Kohlrausch, and others, then so long as the frictional or 
viscous resistance they meet with varies simply as their velocity, Ohm’s 
law is obeyed. But for very strong currents it is possible that the fluid 
friction may vary according to a higher power of the speed, and if so, the 
E.M.F. needed to drive a given current would be a little higher than that 
calculated from Ohm’s law. 
(b) If the ions are not absolutely dissociated, but exhibit a trace of 
chemical cling, then some finite though small E.M.F. may be needed to start 
a current, and thus a violation of Ohm’s law may occur in the same 
direction as that already suggested, but most noticeable with infinitesimal 
currents. Helmholtz has shown that, for ordinary dilute acid, such an 
effect, if existent, is almost too small for observation; but in some worse 
conducting liquids it might conceivably be found. 
(c) Very viscous or highly resisting electrolytes, such as glass, water, 
turpentine, &c., may show some discrepancy. In fact, this may be treated 
as a separate question, and asked thus : 
2. Is Ohm’s law obeyed by very bad conductors ? 
In other words, is the rate of leakage from a charged electrometer 
simply proportional to the potential with which it is charged, no matter 
what kind of slight earth connection is established? Polarisation 
H.M.F.s are in this case probably too small to have much influence, and 
so the problem is in some respects simplified. The investigation is in 
fact precisely similar to an examination of the accuracy of Newton’s law 
of cooling. 
Surface films. 
' Among bad conductors, the films on the surface of glass rods are to 
be remembered and studied. It would be interesting to know the absolute 
. resistance of some such films, if it be possible to specify their conditions. 
