RATE OF DIFFUSION OF IODINE IN KI 



487 



a space of about 0.5 cm. between the top of the liquid and the bottom of 

 the cork. The cork was slightly hollowed on the under side, and covered 

 with a thin coat of parafKne to protect it from the iodine. The delivery 

 tube was so placed that it tapped the highest point of the under side of 

 the cork (see fig. 1). When it was desired to remove the layers for titra- 

 tion, a very concentrated solution of KI (always having a higher specific 





gravity than that used in the experiment) was slowly run in through the 

 funnel till the air space was exactly filled. Then the stopcock was turned 

 and all excess of the displacing fluid was carefully removed from the funnel; 

 first with a pipette, and then with a rolled bit of filter paper. Next there 

 was introduced into the funnel, and slowly run into the cylinder, the same 

 amount of displacing fluid (strong KI solution) that was in each layer. 

 This was measured in a pipette of the desired size. Thus, layer by layer 



