ON THE THEORY OF SOLUTION. Jol 
lytic facts demand, if one is to avoid admitting that extreme state of 
dissociation which physically seems to be so satisfactory and chemically 
so abhorrent. 
But on this head it seems that no logical argument definitely asserting 
this latter view has been adduced. The fact that solutions do, in many 
respects, as shown by their osmotic pressure for instance, obey gaseous 
laws, is of high interest; but to argue from it that therefore their atoms 
must be in the same state of independent freedom as the atoms of a gas, 
is to commit the fallacy called by logicians ‘the illicit process of the 
major.’ 
Moreover it is not quite apparent why (in Mr. Pickering’s paper, for 
instance) the antithesis of the hydrate theory is supposed to be the dis- 
sociation theory. Free molecules in solution, rather than free atoms, would 
seem to be the opposite to the formation of definite chemical hydrates. 
Lastly he hoped he might be permitted one word on the subject of an 
old communication by Professor Ostwald relating a hypothetical experi- 
ment on statically electrifying an electrolyte, which he controverted some 
year or two ago, and which has been referred to by Mr. Pickering as if it 
were equivalent to a perpetual-motion device. He wished to dissociate 
himself entirely from Mr. Pickering’s position on this point, and to ex- 
plain, what he had not yet had a good opportunity for explaining, that 
his published hostile remarks were made at first with the idea that the 
experiment was related as an experiment, and subsequently with the view 
that it is not very safe to use hypothetical experiments as controversial 
weapons. The view held by Professor Ostwald, that an electrolyte 
charged positively is so charged by reason of its hydrogen atoms looking 
outwards, while if charged negatively its oxygen atoms look outwards, is 
an extremely probable and instructive mode of regarding the matter. But 
an experiment establishing the truth of this view would have no necessary 
bearing on the dissociation controversy; in other words, the experiment 
suggested by Professor Ostwald, even if it could be performed, would not 
be a crucial one. The accepted laws of electrolysis already enable one to 
say what will happen when the minute current of a displaced electrostatic 
charge is passed through a liquid, with as much clearness as one can say 
what happens when a battery is applied to it. There is really no difference 
between the two cases, except the presence or absence of electrodes; for, 
as Professor Fitzgerald has said, the facing-out atoms exist in each case, 
only in one they face the electrodes, and in the other they face the air. 
Professor OstwaLp read the following communication ‘On the Elec- 
trical Behaviour of Semipermeable Membranes’ :— 
If we fill two glass beakers with copper sulphate solution, put in them 
two copper wires connected with a couple of Leclanché cells and a galva- 
noscope, and close the circuit by a siphon filled with any electrolyte, which 
is prevented from mixing with the copper sulphate by covering the ends 
of the siphon with parchment paper, no phenomenon of special interest 
is to be noticed. We have an electrolytic circuit without polarisation, as 
used by Paalzow for the determination of the specific conductivities of 
liquids. By varying the liquid in the siphon only the total resistance of 
the circuit varies, and polarisation does not generally occur. If we fill 
the siphon with potassium ferrocyanide, nothing novel seems to go on at 
the first glance. But if we remember that on the contact of copper salts 
with ferrocyanides a semipermeable membrane of copper ferrocyanide is 
