524 Messrs. Buckmaster and Gardner. Supposed [Aug. 12, 



Table II. 



Temp. 



CHCL in 



Duration 

 of oxygen 

 current in 

 control. 



Duration 

 of oxygen 

 current in 

 experi- 

 ment. 



Iodine liberated 

 in N/1000 sodium 

 thiosulphate in 



Control. 



Experi- 

 ment. 



Iodine 

 liberated 

 by CHCI3 



only in 

 terms of 



thio- 

 sulphate. 



Remarks. 



157 



137 



137 

 100 



per cent. 

 7-9 



4-0 



7-0 

 9-2 



h. in. 

 1 35 



2 



1 20 

 1 -40 



h. m. 



2 5 



1 20 



c.c. 

 3 -4 



4-5 



1 20 

 1 30 



c.c. 

 57 -45 



8-5 



c.c. 

 51 -55 



4-0 "| 



4-0 

 24 -0 



1 -o 



22 -65 



Gas in aspirator 

 smelt of CHCI3. 



In these experi- 

 ments N/1000 was 

 actually used, so 

 that the figures are 

 only approximate. 

 The gas in aspi- 

 rator smelt dis- 

 tinctly of chloro- 

 form. 



[October 12. 1909. — " It was further noticed that when the U-tube (4) con- 

 taining solid potash was eliminated from the circuit, the quantities of iodine 

 evolved underwent a marked diminution. 



When iodine pentoxide is boiled under a reflux condenser with pure chloro- 

 form the action is very slow. One gramme of pentoxide boiled with 5 c.c. 

 of pure chloroform for three hours only gave iodine equivalent to 18'7 c.c. 

 of N/1000 sodium thiosulphate. At higher temperatures the action does not 

 appear to proceed much more rapidly, as the following results of experiments 

 in which iodine pentoxide and chloroform were heated in sealed tubes at 

 temperatures of 100° C. and 137° C. respectively indicate : — 



(1) Weight 

 of I 2 5 . 



Volume of 

 chloroform. 



Temperature. 



Duration of 

 heating. 



Iodine liberated in terms of 

 N/1000 thiosulphate. 



gramme. 



c.c. 





hour. 



c.c. 



1 



1 



100 



1 



13 -9 



1 



1 



137 



1 



21 -1 



In control experiments in which the same weights of iodine pentoxide 

 were heated without chloroform, the quantities of iodine set free were equiva- 

 lent to 1*2 and T4 c.c. of thiosulphate respectively. 



It was clear from these results that although iodine pentoxide reacts with 

 pure chloroform with the liberation of iodine, the amounts so produced are- 



