ASPECTS OF ADSORPTION PHENOMENA 



187 



one kept at 50 C, the other at 10 C. After a certain time the solution 

 was poured off and a new piece of paper and fresh dye solution, 

 previously warmed, or cooled respectively, added and a different time 

 of action allowed. The flasks were thoroughly shaken at frequent 

 intervals to allow access of the solution to the whole surface of the 

 paper. This shaking caused the separation of bits of paper which 

 rendered it necessary to allow the solution to deposit before making 

 colorimeter observations ; neglect of the precaution caused the loss 

 of several of the earlier observations. Filtration is naturally inadmis- 

 sible. The results were as follows, the colorimeter readings expressing 

 the relative percentage of dye left in solution, the original solution 



= IOO. 



Duration of action 



5 minutes 



8 



20 

 33 



4 



IOO 



200 



5 hours 



7 



H 



Colorimeter readings 



5 



95 

 9 



85 

 80 



77 



75 

 75 



circ. 98 



90 



70 

 60 



55 

 48 



45 



FIG. 4 



