352 CAPILLARY ATTRACTION, ETC. [MEMOIR XXVI. 



tendency to be urged from their places towards e and c 

 respectively, and the motion thus produced in a fluid 

 diverges from a rectilinear progress into the unmoved 

 spaces ; and such a pressure taking place in a liquid free 

 to move continually returns the moving particles to 

 their position, after making them describe an elliptical 

 orbit. 



Such is the nature of the evidence that may be brought 

 forward in proof of the hypothesis that the adhesion of 

 surfaces and capillary attraction are electrical results. 

 We may now pass to an exposition and explanation of 

 the more interesting instances of motion in the cases of 

 liquids and gases. If, in the lapse of centuries, metallic 

 copper can part itself from silver with which it has been 

 alloyed, coming forth from the interior of a coin to form 

 a new compound on the surface, such movements, it 

 might be expected, would more readily occur in liquids, 

 of which the cohesion is but small, and in gases, in which 

 cohesion perhaps does not exist at all. 



And, first, as respects liquids : 



The phenomena of endosmosis, first brought to general 

 notice in the case of liquid substances by M. Dutrochet, 

 may be explained as follows : If some alcohol be placed 

 in a bladder, the neck of which is tightly tied, and the 

 bladder be sunk into a vessel of water, percolation en- 

 sues, so that the bladder is distended to its utmost 

 capacity, and may even burst. Or if, instead of tying 

 the mouth of the bladder, a glass tube, open at both 

 ends and a foot or two long, be fastened into it without 

 leakage, as the water introduces itself through the pores 

 of the bladder to mingle with the alcohol the liquid rises 

 in the glass tube, and, when it has reached the top of it, 

 overflows. To express this inward passage of the water 

 the term endosmosis was introduced ; and since a little of 



