44 On certain Phenomena of Capillary Attraction. 



a less cohesive liquid in contact with alkaline solutions than 

 in contact with acids. 



As the flattening of the surface seems to be sufficiently ex- 

 plained by the hypothesis of a powerful attraction between the 

 molecules of the liquids, and as in all observed instances of a 

 flat surface there has been a decided chemical affinity between 

 them, it is difficult to avoid supposing some connexion between 

 the hypothetical attracting force and the actually existing che- 

 mical affinity. If we suppose them to be identical, the attract- 

 ing molecules of the liquids will then be their chemically equi- 

 valent atoms. When chloroform is decomposed by solution of 

 potash, I understand that an atom of chloroform with three 

 atoms of potash produces three equivalents of chloride of po- 

 tassium and one equivalent of formic acid ; which thereafter 

 combines with a fourth atom of potash to form formiate of 

 potash, as expressed by the following equation : 



C 2 H Cl 3 +4KO = 3K Cl + KO, C 2 HO s . 



Supposing, then, the attractions of the liquids to be the same 

 forces which ultimately tend to produce this decomposition, 

 the attracting molecule of potash might be regarded as 4-KO, 

 and that of chloroform as C 2 H Cl 3 : or we may suppose two 

 sets of attracting molecules ; the one 3 CI attracting 3K, and 

 the other C 2 H attracting KO+ 30. But I state this merely 

 to point out what may perhaps have already suggested itself 

 to the reader, that whatever view is taken of this molecular 

 action, the ratio of the number of attracting molecules in the 

 two liquids must still be inversely as the number of molecules 

 in the infinitesimal element of the surface of the liquids sub- 

 jected to that attraction ; and thus the result which has already 

 been arrived at will remain entirely unaffected. 



In conclusion it may be remarked, that if the phaeno- 

 menon of the flattened surface of two immiscible liquids has 

 received a correct explanation on the hypothesis of a strong 

 mutual attraction of their molecules, and if this phaenomenon 

 is found to appear only in cases where the liquids have a de- 

 cided chemical affinity for each other, an interesting connexion 

 is thereby established between chemical affinity and the me- 

 chanical force of adhesion, tending to prove that they are 

 modifications of the same force ; while the whole subject of 

 the mutual attraction of two liquids opens up an interesting, 

 and, so far as I am aware, a new field of inquiry in capillary 

 attraction. 



