2 Jones, Action of Hydrogen on SiiLphiuic Acid. 



acid heated to 250° C, whereas at that temperature the con- 

 centrated acid was rapidly acted on. lie also found there 

 was no reaction between hydrogen and sulphur dioxide heated 

 either to 100° or 280° C. 



The last paper to which I will refer is one by Jaroslav 

 Milbauer (Zeit. Phys. Chem., IQ07, 649) who maintains that 

 impure hydrogen bubbled through sulphuric acid at the ordin- 

 ary temperature contains appreciable quantities of sulphur 

 dioxide, while pure hydrogen gives none. Further, the rate 



of oxidation of pure hydrogen by sulphuric acid was studied 

 in detail at 174° C. at constant pressure. For a given rate of 

 jiassage of the hydrogen the amount of sulphur dioxide per 

 minute is constant for acid containing gi to 97 per cent, of 

 Ho SO4. Also, that the amount of sulphur dioxide produced 

 is increased by catalytic agents, notably by the presence of 

 metals of the platinum group. These results are in close agree- 



