102 



Mr. W. B. Hardy. On the Mechanism of 



The following figiires illustrate the variation in the composition of 

 the fluid as the gel becomes more completely expressed i — 



Successive equal quantities of Expressed Fluid contain Dry Agar in 

 100 c.c. T. = 14°. 



Experiment I. Experiment II. 

 0-12 0-11 

 0-14 0-12 

 0-1 0-09 



The mechanical pressure used to separate the phases will modify their 

 .composition by deforming the surface of separation. This error cannot 

 be estimated. 



The Influence of the Ratio of the Masses of the Two Components upon the 

 Composition of the Phases, 



Two portions of a fairly concentrated gel were taken. To one part 

 water was added to dilute it, and both were then heated to 100°, and 

 equal portions of each were poured into two glass stoppered cylindrical 

 vessels of identical shape, make, and size. The two vessels were then 

 set aside to cool. 



After forty-eight hours samples were cut from different levels in each 

 gel, and used to determine the percentage composition. 



Five hundred and eighty grammes of each of the gels were then 

 expressed. The results were as follows : — 





Agar in 

 100 grams 

 of the gel. 



Expressed fluid. 



Solid solution. 



Yolume. 



Agar. 



Volume. 



Agar. 





grammes. 



c.c. 



per cent. 



c.c. 



per cent. 



T. = 18° 



1-1 



440 



0-1 



140 



4-7 





3-3 



230 



0-14 



350 



5-6 



In another experiment — 









T. = 15° 



3 -6 





0-12 









2-2 





0-14 







Thus an increase of the concentration of agar in the mixture pro- 

 duces an increase in the concentration of the agar in both phases. An 

 explanation of this relation is suggested, and discussed later. 



