Physical Cause of Endosmosis. 283 



tube, under the same circumstances, raised the solution of 

 muriate of soda, the density of which was T06, to a height of 

 9^ lines, and the solution, the density of which was 1*12, to a 

 height of 6^ lines. Hence result the following calculations : 



1st. The capillary ascension of the water being 12. 



And that of the first solution 9.125 



The excess of the capillary ascension of the water is 2.875 



2nd. The capillary ascension of the water being 12. 



And that of the second solution 6.25 



The excess of the capillary ascension of the water is 5.75 



These two excesses are precisely in the proportion of 1 to 2, 

 the same proportion which was found resulting from the expe- 

 riments on the force of endosmosis produced by bringing the 

 two saline solutions in relation with pure water. Thus we 

 find the excess of the capillary ascension of pure water over 

 that of the liquid opposed to it, which is denser, and conse- 

 quently rises the least, determines the force of the endosmosis, 

 which latter is, therefore, a special result of the capillary force. 



The only action of the difference in the density of the liquids 

 is to produce difference of their capillary ascension, so that 

 liquids of smaller density, which have a different capillary 

 ascension, produce an endosmosis differing, and in proportion 

 to the degree of their power of ascension : thus I have 

 found that a solution of sulphate of soda, brought into rela- 

 tion with pure water, produced an endosmosis double of that 

 which a solution of muriate of soda of the same density pro- 

 duced under the same circumstances. The cause of this is 

 found in the measure of the capillary ascension of the two 

 solutions. The capillary ascension of water in a glass tube 

 being 12 lines, that of the solution of sulphate of soda, the 

 density of which was 1-085, was 8 lines, while that of the 

 solution of the muriate of soda, of the same density, was 10 

 lines. The excess of the capillary ascension of the water over 

 that of the solution of sulphate of soda is 4, and over that 

 of the muriate 2, or in the proportion of 2 to 1. Now this is 

 precisely the proportion of that existing between the endos- 

 mosis produced in the experiment made by placing each of 

 these solutions, of equal density, but different capillary ascen^ 



