156 Mr. Davy on a new fulminating platinum. 
nected with the formation and decomposition of the fulmi- 
nating powder will, I presume, prove the correctness* of this 
opinion. 
When the triple compound of oxide of platinum, sulphuric 
acid and ammonia, is boiled in a solution of potash or soda, 
some ammonia is expelled, fulminating platinum is formed, 
and the residual fluid affords a copious white precipitate 
with the soluble salts of barytes and lead ; and if it is evapo- 
rated nearly to dryness, crystals of sulphate of potash or 
soda are obtained. These results appear to be connected 
with the following changes. The triple compound is decom- 
posed, its sulphuric acid unites with the fixed alkali, the 
ammonia it contains being in greater quantity than can com- 
bine with the oxide of platinum, is in part expelled ; the 
remainder enters into a more intimate union with the oxide, 
and thus fulminating platinum is formed. 
In the decomposition of fulminating platinum by heat in 
close vessels, nitrogene and ammoniacal gases, platinum and 
water appear to be the only products ; and these results cor- 
respond with those derived from the agencies of muriatic 
and nitrous acids on the powder. 
From the close analogy that exists between fulminating 
platinum and fulminating gold in their properties and consti- 
tution, they must be regarded as belonging to the same class 
of bodies, and the theory which explains in a satisfactory 
manner the decomposition and fulmination of the latter, will 
likewise serve to account for similar changes in the former. 
Whilst the composition of fulminating gold was unknown,, 
various explanations as to- the cause of its explosive properties 
