Gooch and Blumenthal — Use of Selenic Acid. 59 



to 110° by means of an oil bath heated to 120° to 130°. The 

 details of experiments with this apparatus are given in the fol- 



lowing 



table : 





Table III. 









Tests with Selenic 



Acid, and the Relay Apparatus. 











Final volume 







Br token 



Taken 



H 2 Se0 4 



H 2 Se0 4 in reaction 



Br 





asKBr 



NaCl 



I 



II flask 



found 



Error 



grm. 



grm. 



cm 3 . 



cm 3 . cm 3 . 



grm. 



grm. 



0-0675 



0*0050 



5 



2-5 12-13 



0-0671 



— 0-0004 



0-1350 



0-0050 



5 



2-5 15 



0-1339 



— 0-0011 



0*1013 



0*0050 



5 



2-5 12-13 



0-1003 



—o-ooio 



0-0675 



0-1505 



5 



2-5 15 



0-0672 



— 0-0003 



Fig. 2. 



So far as may be judged from the few results of Table IV, 

 the use of the second voit flask to repeat the contact with 

 selenic acid is favorable, and this evidence is confirmed in the 

 work which follows, in which sulphuric acid and a selenate 

 were used to generate the selenic acid in the reaction flasks. 

 There is still a constant error of deficiency in the bromine, 

 averaging 0*0007 grm., which might suggest that, in reversal 

 of the fundamental reaction by which bromine is set free, the 

 reoxiclation of selenious acid by bromine is a possibility even at 

 the final concentration. If this were the case, the addition of 

 more selenic acid and further concentration of the solution in 

 the reaction flask should advance the main reaction ; but the 



