Mr. Davy on a new fulminating platinum. 157 
were given by the early chemists ; but they were in general, 
as might have been expected, so vague, and so obscurely de- 
veloped, as to be at best but unintelligible enigmas. The 
researches of Bergman fully exposed and refuted all pre- 
vious opinions on the subject, and led to just views concerning 
the nature of aurum fulminans^ He stated it to be composed 
of calx of gold and volatile alkali, and he referred its fulmi- 
nation to the decomposition of the alkali, and the great report 
and violent explosion to a copious and instantaneous eruption 
of elastic fluid violently striking the air * The theory of its 
decomposition was explained by M. Berthollet in a still 
more satisfactory manner, when the composition of ammonia 
was discovered. On this theory, when the fulminating gold 
is exploded, ammonia is decomposed, its hydrogene unites to 
the oxygene of the oxide to form water, the gold is reduced, 
and nitrogene gas disengaged. The sudden expansion of the 
air and vapour generated in the process, are circumstances 
connected with the detonation. The decomposition of ful- 
minating platinum admits of a similar explanation ; but with 
the changes already enumerated, we must connect the disen- 
gagement of ammoniacal gas, and the instantaneous conver- 
sion of the water of composition in the fulminating powder 
into steam, and these effects are probably intimately connected 
with the exhibition of its fulminating properties, 
* Physical and Chemical Essays, Vol. II. 
Cork, December 20 , 1816. 
