Ordinary Meeting, December 1st, 1874. 
Rev, Wm. Gaskell, M.A., Vice-President, in the Chair. 
Some Doubts in regard to the Law of the Diffusion of 
Gases,” by Henry H. Howorth, Esq. 
The Author said that he had a difficulty in reconciling 
the conclusions drawn by Dalton, Berthollet, and Graham 
respecting the diffusion of gases with the actual facts of 
nature, and it seemed to him that the only way in which 
the inferences drawn from experiments in the laboratory 
and what was going on in nature on a large scale could be 
reconciled was in the belief that either diffusion was ex- 
tremely slow in some cases or that it was sometimes 
prevented. 
He argued that the continuity of condition between 
gases and liquids which had lately been so admirably illus- 
trated made it, a priori, probable that similar laws prevailed 
in both classes of matter in respect to their laws of diffu- 
sion, &c,, and that, as in the case of liquids, the law of 
diffusion was not a universal one, but had at least apparent 
exceptions, so also among gases there might occasionally be 
conditions which resisted or very greatly impeded the 
operation of the law. He granted at once that the gases 
that form air, and many others, bear uniform testimony to 
the correctness of the generalisation ; but in the case of 
carbonic acid, watery vapour, and hydrogen, there seemed 
to be some room for doubt. The fact that in all abandoned 
wells, tunnels, and mines, where atmospheric currents do 
not play, and where there is no absorbing vegetation, there is 
an accumulation of carbonic acid gas, although these hollows 
have ample access to the air, goes to show that the rate of 
diffusion must be exceedingly slow in these cases, if in fact 
diffusion be not actually suspended. The mephitic vapours 
Proceedings— Lit. & Phil. Soc.— Yol. XIY.— No, 5.— Session 1874-5. 
