Capillary Attraction exhibited by Chloroform^ 8^c. 39 



It thus appears that the attraction of the alkaline solution 

 for glass is greater than that of the acid ; for it is capable of 

 supporting a column of 2*9 inches, while that of the acid, 

 although it is a lighter fluid than the solution of potash, can 

 only support a column of 2*7 inches. In order to remove 

 any doubt as to the superiority of the alkaline solution to the 

 acid in attraction for glass, I made a weaker solution of 

 potash, and repeated the experiments on chloroform with it 

 and another sample of hydrochloric acid. The following 

 table shows the heights at which these liquids stood in two 

 different thermometer- tubes, as determined by the mean of 

 three observations. 



It will be observed in the second set of experiments, that 

 the alkaline solution is lighter than the acid, so that it is not 

 obvious by inspection of the table which has the strongest 

 attraction for glass. But supposing the attractions the same, 

 the heights of the columns should be inversely as the specific 

 gravities ; so that, taking the acid as the standard, the height 

 of the column of solution of potash in the tubes should be 1*60 

 and 3"94, instead of which the observed heights are 1*77 and 

 4 '61, showing that in this case also the alkaline solution has a 

 stronger attraction for glass than the acid. We have thus 

 the remarkable fact, that solution of potash, which has a much 

 stronger attraction for glass than that possessed by hydro- 

 chloric acid, is actually less able to wet it in the presence of 

 chloroform. It follows also, that we cannot explain the flat- 

 tened surface of the chloroform in the presence of the solution 

 of potash, on the supposition of a nearly equal attraction of 

 the liquids for glass ; for those liquids obviously differ greatly 

 in this respect, as the one rises in a capillary tube to nearly 

 four times the height of the other. According to this view, 

 as the attractions of chloroform and acid for glass differ less 

 than those of chloroform and alkaline solution, the surface of 

 chloroform in contact with acid in glass vessels should be less 

 curved than when it is in contact with an alkaline solution ; 

 but precisely the reverse of this is the case. 



it may be proper to mention, that, having carefully ascertained the specific 

 gravities of five different specimens of rectified chloroform, I have found 

 them to vary from 1-493 to 1-497. 



I 



