Theory of Colloidal Solution. 649 



AB. Then de is acted on by two forces r and I, as indicated 

 in the diagram, / being due to the attraction of I and r to 

 that of 0. For crystalline solids l>r; for "colloidal" 

 matter in contact with certain liquids we assume that r>L 



D) 



Fig. 1, 







& 7*- > j- | Q 





C 



It follows then that the solid I will begin to disintegrate into 

 the liquid medium 0. It is difficult to form an accurate 

 mental picture of what exactly happens in this case. Probably 

 the solid "mixes'" into in the form of excessively thin 

 sheets or extremely fine and branching filaments. It must 

 be observed that the colloidal solid is not in an " explo- 

 sive ,J state, for the disintegration only affects at any moment 

 the excessively thin surface-layers. The question now arises 

 as to how far this process will continue ; for if it be supposed 

 to go on until the limit of molecular intermixture be arrived 

 at, it is evident that a true solution must result. But as we 

 understand by colloidal matter that condition of matter which 

 gives " colloidal solutions " (defined by certain peculiar 

 properties), it is clear that there exists something which 

 arrests the disintegration-process before the molecular limit 

 is arrived at, and yet at a point where the resulting " grain " 

 is exceedingly fine. The essence of the theory here proposed 

 lies in the nature of the assumptions whereby this stoppage 

 of the process of disintegration or intermixture is accounted 

 for. 



Let the attraction of the matter contained in the semicircle 

 PQR be a very large percentage of the attraction due to the 

 infinite (or practically infinite) mass of lying to the right 

 of de. Let similarly the attraction due to LMN be the same 

 very large percentage of the total attractive force exerted on 



Phil. Mag. S. 6. Vol. 1. No. 6. June 1901. 2 U 



