Laws of Absorption of Liquids by Porous Substances. 367 



In this expression we may consider that the space is estimated 

 from a point situated at /3 inches from the level of the liquid, 

 and that the time is estimated from a period of time p minutes 

 anterior to the actual commencement of the motion. 



When /3=0, oris very small, as it is in most of the results ob- 

 tained for the diffusion of water, then equation (4) becomes 



v= WfF) (5) 



Now when T is large as compared with p 3 or when p is 

 neglected, we have 



«*m < 6 > 



Experiment II. 



The absorbent in this experiment was very thick unsized paper, 

 2 inches wide, and weight 1*18 gr. per square inch. The tem- 

 perature was 60° throughout the experiment. The formulas in 

 this case are 



T=3-3S 2 -l-3, (7) 



and 



•~sfe < 8 > 



