4:80 ABSOBPTION. 



the liquid. The elevation of the liquid can therefore be in- 

 creased by diminishing the amount of liquid and increas- 

 ing the extent of the attracting surface. This is illustrated 

 by a modification of the last experiment. If the surface -of 

 the liquid near the plate of glass be carefully examined, it 

 will be found to present a curve, which extends from the 

 highest point to which the liquid has ascended on the glass 

 to the general level. If we now divide the liquid into im- 

 aginary parallel strata of infinite thinness, it is evident that 

 the layer of liquid next the glass is most powerfully attracted 

 and has mounted highest ; that the second stratum, being 

 removed from the surface, is less powerfully attracted, and is 

 influenced to a greater degree by the cohesive attraction be- 

 tween the molecules of the liquid ; and that, as we recede 

 from the glass surface, the attractive force is progressively 

 diminished and the cohesive force progressively increased, 

 until, when the general level of the liquid is reached, the at- 

 tractive force is lost. Suppose now that a second plate of 

 glass be placed parallel to the first, the liquid between the 

 two plates will be subjected to double the amount of attrac- 

 tion, and will form a concave surface, the lowest point being 

 equidistant between the two plates. The nearer these two 

 plates are brought together, the smaller will be the quantity 

 of liquid, and the molecular attraction between its particles 

 will necessarily be proportionately diminished. This may 

 be shown by approximating the glasses at one end, and 

 progressively increasing the distance between them to the 

 other. The liquid will then form a curve between the plates, 

 the highest point being where they are most closely approx- 

 imated. 



If tubes be used instead of plates of glass, the foregoing 

 facts are more strikingly illustrated. The nearer the internal 

 surfaces of. the tube are brought together, or, in other words, 

 the smaller the calibre of the tube, the greater will be the 

 elevation of liquid in its interior. It is because liquids are 

 observed, in accordance with this law, to mount highest in 



