Capillary Attraction exhibited by Chloroform^ 8fc. 4- 1 



chloroform is opt to become concave in contact with it under 

 water or acid. On lining a glass tube with a thin coating of 

 wax, I found that chloroform placed in it under hydrochloric 

 acid had a very concave surface, while on supersaturating the 

 acid with solution of potash the surface became sensibly flat. 

 Similarly, chloroform under water in a quill has a very concave 

 surface, which becomes sensibly flat on the addition of potash, 

 and the concavity is restored by adding a sufficient quantity 

 of hydrochloric acid. It will be observed that the coating of 

 wax, or the substitution of a tube of quill for one of glass, 

 while it completely reverses the curvature of the chloroform 

 in contact with water and acids, exerts apparently no influence 

 on the power of the alkali to flatten its surface ; and the con- 

 clusion seems inevitable, that this effect depends upon a mutual 

 action of the liquids, and is quite independent of the nature of 

 the containing vessel, for it takes place equally in contact with 

 surfaces of glass, platina, iron, wax, or quill. 



Having thus endeavoured to show that the flatness of the 

 surface of chloroform under alkaline solutions is independent 

 of the equality of the attractions of the liquids for the walls of 

 the vessel, of the equality of their cohesive powers, and of the 

 nature of the containing vessel, it only remains to inquire how 

 it may be explained on the supposition of an attractive force 

 between the liquids themselves. 



The form of the surface of the liquids in contact with the 

 walls of the containing vessel will evidently depend, — 1, on the 

 mutual attractions of the particles of each fluid ; 2, on the 

 attractions of the particles of one fluid upon those of the other ; 

 and 3, upon the attraction of the walls of the vessel for both 

 fluids. Considering the second of these forces, we may suppose 

 it to act upon an indefinitely small element of the surface of the 

 liquids, at its contact with the walls of the vessel, consisting of 

 equal small contiguousvolumes of solution of potash and chloro- 

 form. All the molecules of chloroform it contains will then be 

 attracted by all the molecules of the solution of potash within 

 the sphere of sensible attraction, while all the atoms of solution 

 of potash it contains will be solicited by a similar attraction 

 of the molecules of chloroform. Now since the attracting 

 forces are identical in both cases, each individual attraction 

 being that of a molecule of solution of potash to a molecule of 

 chloroform, the sphere of sensible attraction will evidently 

 extend to the same distance on both sides, and comprehend 

 equal volumes of both liquids. But as the attracted particle 

 also contains equal small volumes of chloroform and solution 

 of potash, it is evident that the number of the attracting mo- 

 lecules of solution of potash will have, to that of the molecules 



