200 KANSAS UNIVERSITY QUARTERLY. 



Exp. 4. One c. c. of hydrochloric acid was placed in a glass tube 

 having a constriction near the open end. .20 grammes of platinum was 

 then introduced a few inches beyond the constriction. Hydrogen 

 was then passed into the tube by a slender tube reaching nearly to 

 the bottom. The platinum was then heated for some time to expel 

 all the oxygen which might have been condensed on the surface. An 

 apparatus for generating hydrochloric acid gas was substituted for 

 the hydrogen generator, and hydrochloric acid gas passed through the 

 tube for some time. The open end of the tube was then closed with 

 a cork and sealed at the constriction. This was heated for twelve 

 hours at from 300 to 360 degrees C. .0045 grams of platinum was 

 obtained from this solution. 



These results in tabular form are as follows: 



Temperature. 



Boiling. 



200 C. 



300 — 360 C. 



300 — 360 C. 



These results would seem to indicate that the oxygen of the air 

 plays an important part in the solution, being condensed on the sur- 

 face of the platinum and then acting on the hydrochleric acid, setting 

 free chlorine, which then unites with the platinum to form platinic 

 chlorid. We think it probable that if all the air could be removed 

 from the apparatus, the platinum would be entirely unattacked. 

 Further experiments with this and other acids will be undertaken. 



