On the Laws of Absorption of Liquids by Porous Substances. 501 



point A, which stood about half an inch from the level of the 

 liquid. 



The line formed upon the surface of the absorbent by the 

 liquid throughout the course of its diffusion, was a perfect semi- 

 circle, B D C, having the point A as its centre. The breadth 

 of the absorbent being 3 inches, the semicircle attained its 

 greatest diameter at S = 1'5 inch. After this the line of liquid 

 absorption became a curve of contrary flexure, EKF, having 

 points of contrary flexure at E and F, which may be mathemati- 

 cally explained on the assumption of the law of equal diffusion. 

 The point A appeared to form the central point of liquid diffu- 

 sion, from which the liquid was diffused equally in all directions. 



The same results were obtained with an ab- 

 sorbent cut in the form represented in the an- 

 nexed diagram. 



The following experiment was made to de- 

 termine the manner in which the liquid^diffuses 

 itself over the surface of the absorbent. 



Experiment VI. 

 This experiment was made with 

 the apparatus represented in the an- 

 nexed diagram. H G the absorbent 

 suspended in the jar AB, contain- 

 ing a small portion of water, by means 

 of a hooked wire, G S, attached to the 

 pan C of a delicate balance ; E F a stage 

 supporting the pan of the balance : 

 this stage admits of being raised or de- 

 pressed as may be required, and the 

 adjustment is such that the lower edge, 

 H, of the absorbent shall exactly come 

 in contact with the surface of the water, 



