ON THE THEORY OF SOLUTION. 329 
dissent from this. The two theories are essentially the same. There 
have been unnecessary assumptions no doubt made as to how far an 
absolute independence of motion of the ions is required by the experi- 
ments, and I combat this unnecessarily absolute independence, but in all 
essential respects my theory is the same as the other. This unnecessarily 
absolute independence has been introduced in order to make what is 
acknowledged to be an ‘analogy’ appear as if it were more than an 
analogy, to give verisimilitude to what is at the same time said to be 
merely a facon de parler, to make what is known to be complicated appear 
unreally simple. 
It may be worth while following Professor Armstrong’s suggestions 
that the way in which the double decomposition is facilitated by a sol- 
vent is by the two salts entering into combination with the solvent and 
forming a large molecule. Then by a process of tautomerism! by which 
the elements within a molecule exchange places the double decomposition 
is effected. A similar but regulated rearrangement under electric forces 
would account for electrolysis. That solution is a true chemical combina- 
tion seems undoubted. There is change of nature—e.g., solid salt and ice 
change into liquid—redistribution of energy, change of volume, every 
change significant of chemical action; and that solution can be saturated 
shows that there is combination in definite proportions, even though 
some doubt may exist as to the existence of cryohydrates. In speaking 
of solvents as merely giving molecules space wherein to resolve them- 
selves into ions, it seems as if the part of Hamlet were left ont. The 
action of the solvent is to cause ionisation, some solvents do it and some 
do not, and it is rather hard on these strangely active solvents not to 
recognise this activity, one of the most wonderful and effective of all 
chemical actions known to us. 
As regards the energy required for dissociation, or, as I would prefer 
to call it, ionisation, I agree with Professor Ostwald that any required 
supply can be obtained by assuming either an affinity of the element for 
electricity (a form of words I object to for reasons to be presently stated) 
or by supposing the ionic state to be an allotropic form of the atom with 
a different internal energy in it from that in the atom when in combina- 
tion. The reason I object to the term affinity of the atom for electricity 
is that all we know’of electricity seems to show that if any body attracts 
positive electricity it repels negative, and in that case the atom and its 
electrical charge combined would not be acted on by electrical forces as 
is required in order to explain electrolysis. I do not like the idea of an 
_allotropic form of the atom, and think the facts of solution, &c., can all be 
explained by chemical combination between the salt and its solvent, as 
I have described, without this assumption. A good deal of weight has 
been laid on the explanation of the equality of heats of neutralisation of 
ionised bodies by supposing them to be dissociated. The explanation 
only pushes the difficulty one step further back. How does it happen 
that the heats of ionisation or dissociation during solution are many of 
them so nearly balanced by the allotropism of the ionic state? We are 
only explaining the obscure by the more obscure in thus reasoning. It 
is perfectly plain that double exchanging can never be continually taking 
place between molecules unless the heats of combination are the same, 
and consequently anything that explains one will explain the other. I 
_ ' Professor J. Emerson Reynolds informs me that such redistributions are recog- 
nised as occurring in complex molecules. 
