Matichester Meuioh's, Vol. xlvii. (1902), No. 1. 5 



These results are very different indeed from those of 

 Orton and Blackman, and the difference is entirely due 

 to the different methods of procedure. In the first place, 

 the iodine they used was not sufficiently finely divided. 

 I have tried the experiment using iodine which had been 

 powdered for a long time in a mortar, with the result 

 that the amount of iodine in the filtrate as hypoiodite 

 was only from 10 to 20 per cent, of the possible amount, 

 showing that powdered iodine is not half so good as the 

 precipitated. 



In the second place, they took too long over their 

 experiments. I have tried experiments where the shaking 

 with the mercuric oxide was continued for varying lengths 

 of time, up to 15 minutes, using precipitated iodine. The 

 following Table shows the results obtained in one set 

 of five experiments : — 



It is evident that the amount of iodine present as 

 hypoiodite diminishes rapidly as the time of shaking with 

 the mercuric oxide is extended. 



The filtrate always contains a little mercury, which 

 usually separates out as mercuric iodide on long standing. 

 The mercury possibly exists at first as hypoiodite. I 

 have made one determination of the amount of mercur\- 



