194 



Gooch and Browning — Method for the 



urinations of Series G-, when the percentage reaches twenty- 

 eight and a half. It remains to be seen whether the arsenions 

 oxide reduced in the separation of the iodine will resist success- 

 fully, under the conditions of these experiments, the tendency 

 to volatilize which the presence of chlorides and bromides, and 

 the consequent liberation of hydrochloric and hydrobromic 

 acids, might presumably induce. 



The experiments of Series I were directed to the elucidation 

 of this point. 



Decinormal solutions of iodine and arsenious acid prepared, 

 standardized, and tested against one another in the usual man- 

 ner. Definite portions of the solution of arsenious acid were 

 measured from a burette into Erlenmeyer beakers such as were 

 used in the previous experiments, sulphuric acid [1 : 1], and 

 sodium chloride were added, the volume of the liquid was ad- 

 justed to 100 cm 3 , or a little more, and the process of concen- 

 tration by boiling was carried to the point desired and indi- 

 cated by a mark upon the flask. After cooling, the acid was 

 neutralized and the titration effected in the usual manner in 

 the presence of an excess of acid potassium carbonate and 

 starch employed as the indicator. These experiments were 

 arranged upon the presumption that the essential conditions 

 determining the degree of volatility of the arsenic when the 

 reduction is effected by hydriodic acid are imitated, though 

 neither* hydriodic acid, nor arsenic acid, nor free iodine is 

 present. 



Series I. 



H 2 S0 4 



NaCl. 



Final ' 



[1:1 j. 



volume, i 



flOcm 3 



1 grm. 



20 cm 3 



1 io 



1 



20 



(10 



1 



20 



1 io 



0-8 



20 



lio 



0-5 



20 



Per cent of J 



strong H 2 S0 4 



by volume. : 







25 

 25 

 25 

 25 

 25 



As 2 3 

 taken. 



As 2 3 

 found. 



Loss. 



0-0495 gr. 



0-0495 



0-0495 



00495 



0-0405 



0485 gr. 



0493 



0488 



0488 



0495 



0010 gr. 

 0002 



0007 

 0007 

 0000 



f 20 



1 



40 



20 



1 



40 



<{ 20 



0-8 



40 



20 



05 



40 



20 



0-5 



40 



f 20 



1 



30 



■{ 20 



0-8 



30 



20 



0-5 



30 



20 



05 



30 



20 



0-5 



30 



20 



05 



30 



1^20 



05 



30 



25 



25 



25 



25 



25 



33 



33 



33 



33 



33-3 



33-3 



333 



0495 

 00495 

 0495 

 0-0495 

 01 385 

 00495 

 0-0495 

 00495 

 00495 

 0-0595 

 00495 

 0-0495 



0490 

 0490 

 0490 

 0490 

 1380 

 0476 

 0466 

 0481 

 0485 

 0490 

 0490 

 0490 



0005 



0005 



0005 



0005 



0005 



0019 



0029 



0014- 



0010 



0005 



0005 



0005 



f30 

 30 

 30 

 30 



1 



0-8 

 08 

 0-5 



60 

 60 

 60 

 60 



25 

 25 

 25 

 25 



0-0495 

 0-0495 

 0-0495 

 0-0495 



0485 

 0490 

 0490 

 0490 



0010 

 0005 

 0005 

 0005 



