390 Prof. G. N. Antonoff on Jnterfacial 



circumstances. To obtain more or less reliable results only 

 liquids with considerable differences « 12 must be chosen to 

 prove the above law. For this reason in the above table water 

 exists as one o£ the constituents in all pairs. Water has an 

 exceptionally high surface tension o£ the order of magni- 

 tude 70 ^y™^ anc [ t ne majority of other liquids about 

 cent. j </ j. 



20-30 ^ es . Therefore only in solutions having water as 



cent. J & 



It is apparent that the liquid will wet the glass in the case where the 

 value of the attraction between the glass and the liquid is greater 

 than between the particles of the liquid, i. e. if 



d 2 ± ^ d^ 



.' It must be admitted that d x and d 2 are little different from each other 

 (and in all cases different less than h and l 2 ), and in this case the condition 

 of humectation will be 



h > h. 



Let us try to explain the fact observed empirically that when two 

 liquids are in contact with the glass (each of which wets the glass), the 

 liquid possessing the highest surface tension will wet the glass replacing 

 the other liquid. 



Let us designate by h, l 2 , and l 3 the reciprocal dimensions of the 

 doublets of the first and second liquids and of the glass. We shall have 

 that the attraction between the glass and the first liquid will be given by 



3eH x h 



d l ' 



The attraction between the glass and the second liquid will be 



Se%l 3 

 d± ' 



It is evident that the first liquid will wet if 



k > h. 



However, experience shows that the condition of humectation is 

 alwavs 



«! > 062- 



If we assume pi = p 2 , 



then the condition Z, > l 2 



is equivalent to a x > a 2 . 



