PHILOSOPHICAL 
TRANSACTIONS. 
XI. On the Action of Nitre upon Gold and Platina. By 
Smithson Tennant, Esq . F. R. S. 
Read March 23, 1797. 
Gold, which cannot be calcined by exposure to heat and 
air, has been also considered as incapable of being affected by 
nitre. But in the course of some experiments on the diamond, 
an account of which has been communicated to this Society, I 
observed, that when nitre was heated in a tube of gold, and 
the diamond was not in sufficient quantity to supply the alkali 
of the nitre with fixed air, a part of the gold was dissolved. 
From this observation I was induced to examine more particu- 
larly the action of nitre upon gold, as well as to inquire whe- 
ther it would produce any effect upon silver and platina. 
With this intention I put some thin pieces of gold into the 
tube together with nitre, and exposed them to a strong red 
heat for two or three hours. After the tube was taken from 
the fire the part of the nitre which remained, consisting of 
caustic alkali, and of nitre partially decomposed, weighed 
MDCCXC VII. G g 
