MUTUAL SOLUBILITY OF LIQUIDS. 91 



Closely akin to the phenomena of occlusion, or solution of gases 

 in the body of solids, are various physical actions, whereby gases 

 are strongly attracted to and condensed upon the surfaces of 

 solids, more especially when these are of a highly porous nature. 

 These surface actions will, however, be more conveniently dis- 

 cussed later on (Chapter XVII.). 



CHAPTEK VIII. 



MISCIBILITY OF LIQUIDS, OR MUTUAL SOLUBILITY OF LIQUIDS IN 

 ONE ANOTHER, NO CHEMICAL ACTION TAKING PLACE. 



It is a matter of every day observation, that whilst certain 

 fluids will mix readily together, no matter in what relative propor- 

 tions they are used, others will not do so, at any rate when 

 employed in anything like equal quantities ; thus spirits of wine 

 (alcohol) and water are a pair of fluids that will dissolve in each 

 other or intermix in all proportions ; whilst olive oil and water 

 are a pair of fluids practically quite insoluble in one another, 

 and quite incapable of intermixture; as again are mercury and 

 alcohol. 



Many cases are known where two fluids are intermiscible in 

 certain proportions, but not in others ; this occurs when the first 

 fluid is soluble in the second, but only slightly so; and when 

 the second is similarly soluble in the first, but only to a limited 

 extent. Thus, if a few drops of ether are added to a pint of 

 water, or a few drops of water to a pint of pure (anhydrous) ether, 

 and the whole well shaken, the smaller quantity of the one fluid 

 will permanently dissolve in the larger quantity of the other, 

 and one single uniform fluid or solution will in either case be 

 obtained. But if you put into a bottle equal bulks of ether and 

 water, and shake them up well together, and then allow the whole 

 to stand awhile, the liquid will separate into two layers, as oil 

 and water would do ; but with this difference, that the upper layer 

 is not pure anhydrous ether, but is ether containing as much 

 water dissolved therein as it can possibly take up : whilst 

 similarly, the lower layer is not plain water, but is a saturated 

 solution of ether in water. 



If quicksilver, distilled water, and pure ether be shaken up 

 together, on standing three layers will be formed ; the lowest being 



