18:26.] Scientific 'Notices^Chemistrp 71 



sary to cool it down through the long space of nearly 400^, or to 

 212° Fahr. Such a reduction below the degree of temperature 

 at which the absorption took place, would be productive, in all 

 probability, of liquefaction in the case of the most refractory of 

 the gases. Now a composition of sulphuric acid and water, the 

 same in every respect, might be obtained more directly by sim- 

 ply mixing together the ingredients, both being in the liquid 

 state. This case of the absorption of a gaseous body by a 

 liquid is, therefore, dependent upon the affinity which occasions 

 the miscibility of liquids, and is, in fact, an instance of the mix- 

 ture of two liquids. Many similar illustrations might be adduced 

 if required. 



We are, therefore, authorized in concluding that gases may 

 owe their absorption by liquids, — to their capability of being 

 liquefied, and to the affinities of liquids (apparent in their misci- 

 bility), to which they become in this way exposed. These pro^ 

 perties may, therefore, be considered as the proximate or 

 immediate causes of the absorbability of the gases. Upon this 

 supposition, solutions of gases in liquids are mixtures of a more 

 volatile with a less volatile liquid ; and to them may be extended 

 the laws which hold in such mixtures. 



Several circumstances are favourable to this view of the 

 absorption of gases. 



1 . The cause assigned is one which we know to exist, and to be in 

 operation. It is no suppositious cause of the existence of which 

 we can adduce no other evidence, than its conveniency in ex- 

 plaining certain phenomena. We possess evidence that almost 

 all the gases may be condensed into liquids. They are, therefore, 

 necessarily under the influence of those causes which we have 

 supposed to occasion gaseous absorbability. Thus : Mr. Fara- 

 day condensed sulphurous acid gas into a liquid, and found 

 that its vapour possessed an elasticity which was balanced by 

 the weight of about 2 atmospheres at 45° Fahrenheit. Here 

 then is a liquid, which, from the frequency of the intermisci- 

 bility of liquids, might be expected to possess the property of 

 mixing so intimately with certain of our reputed liquids, as to 

 admit of being detained by them in considerable quantity at 

 the ordinary pressure and temperature. And, accordingly, sul- 

 phurous acid is absorbed and detained in large proportions by 

 sulphuric acid and by alcohol, and in a considerable measure 

 by water. 



2. It is a coincidence which appears more than accidental, 

 that the gases which yielded to Mr. Faraday are, generally 

 speaking, of easy absorbability. This will appear from the 

 following table of the gases which were liquefied by that expe- 

 rimenter, of the pressure of their vapours in atmospheres, and 

 of the amount of their absorption by water and alcohol at &fy 



