PAPERS OX CHEMISTRY AND PHYSICS 283 



rate of change in the conductance was practically the 

 same for the sols of ditferent initial concentrations. 

 However, on closer examination of the curves for the sols 

 of different concentrations, it will be seen that the slopes 

 at corresponding times increase as the concentration 

 of the sol diminishes. Thus for the eight and sixteen 

 hour periods the slopes are approximately as follows: 



Slopes of the curves for 



lOOrc 75^^^ bO<rc 2o^c 12.5^ 5% 



Time Sol, Sol Sol Sol Sol Sol 



8 hours 600 .581 .675 .750 .725 .781 



16 hours 375 .372 .453 .522 .519 .578 



These figures indicate that the rate of change of conduc- 

 tance increases with decreasing concentration of the sol. 

 The slope of each of the curves gradually becomes smal- 

 ler, and all the curves would eventually become parallel 

 to the time axis and further increase iii conductivity 

 cease if the nins were continued for a sufficient length 

 of time. It was observed that a finely divided whitish 



TABLE OF DATA. 



Specific Conductivity. K X 10"^ 



Time in Hours lOO'-'c Sol 75<~'c Sol 50^f Sol 



18.127 15.333 10.943 



.0S33 18.209 15.413 11.032 



.2500 IS. 444 15.568 11.145 



.5833 18.814 15.918 



1.0833 19.265 16.358 12.008 



2.0833 20.199 17.234 13.004 



3.0833 20.750 17.911 13.799 



4.5833 21.746 18.750 14.809 



6.5833 22.564 19.584 15.867 



9.5833 23.160 20.294 16.717 



15.3833 24.069 21.281 18.097 



25':"c Sol 12.5f^f Sol o^f Sol 



6.898 4.983 2.715 



.2167 7.129 5.204 2.930 



.6500 7.577 5.620 3.333 



1.3167 S.279 6.281 3.953 



2.8167 9.445 7.802 5.372 



5.8167 11.786 9.652 7.250 



11.0667 13.S76 12.036 9.874 



14.6670 14.934 13.027 11.223 



18.0000 15.952 13.741 12.220 



precipitate formecTon the bottom of the conductivity cells 

 in all cases. 



Freundlich and Xathansohir^ have pointed out that 

 the gradual clouding and final precipitation of sulfur fol- 

 lowed bv coagulation of arsenic trisulfide from a care- 



