254 CAPILLARY ATTRACTION. 



the earth, it dissolves and combines chemically 

 with a portion of its mineral ingredients ; after 

 which, it is forced to the surface by hydrostatic 

 pressure, (on meeting with an obstruction to its 

 horizontal progress,) forming innumerable springs 

 and fountains of delicious water. 



It is owing to the attraction of liquids for 

 solids that the dust of our roads, which, when 

 dry, has little or no cohesion, becomes so tenacious 

 after rain ; or that a rope when moistened with 

 water, contracts with great force. The com- 

 bination of tannin with leather, and colouring 

 matter with clothing, are due to a modification 

 of the same power that enables water to com- 

 bine with salts, or to permeate porous rocks. 



Several distinguished philosophers have re- 

 cently conjectured, that a discovery of the cause 

 which determines the rise of liquids through 

 porous solids and capillary tubes, would unfold 

 the latent principle of action in all molecular 

 changes, whether chemical or vital. The trunks, 

 stems, leaves, and flowers of all the trees and 

 plants that adorn the earth, are composed through- 

 out, of exceedingly small capillary tubes and 

 pores that attract liquid nourishment from the 

 earth, and convert it into their own substance, 

 by the same power which causes the combina- 

 tion of other solids and liquids. And so of all 

 animals. Every muscle, gland, nerve, bone, 

 and blood vessel, is composed of imperceptibly 



