13B Mr. Davy on a new fulminating platinum. 
on the detail of its physical and chemical properties, it may 
be proper to notice the methods by which it may be pro- 
cured. 
II. Modes of obtaining Fulminating Platinum . 
In the year 1812, whilst I was engaged in experiments on 
some compounds of platinum, I obtained an ammonia sul- 
phate of this metal, by treating sulphate of platinum with 
pure ammonia. On boiling a little of the ammonia sulphate 
with pure potash, it became of a darker colour. I supposed 
it might have been converted into an oxide, but I did not 
examine it. On recently renewing this enquiry, I was led 
to the discovery of fulminating platinum. 
The platinum I employed, in preparing the fulminating 
compound, it may be proper to remark, was in the form of 
thin sheets, but previous to its being used it was dissolved in 
nitro-muriatic acid, then precipitated by muriate of ammonia, 
and again reduced to the metallic state. 
The platinum so prepared was dissolved in nitro-muriatic 
acid, the solution evaporated to dryness, and the dry mass 
dissolved in water. A current of sulphuretted hydrogene 
gas was then passed through the aqueous solution, till the 
supernatant fluid remained colourless. The hydro-sulphuret 
of platinum, after being well washed and partially dried, was 
converted into sulphate by the agency of nitrous acid. The 
fulminating platinum was prepared, by treating the aqueous 
solution of sulphate of platinum with a slight excess of pure 
ammonia; the precipitate thus obtained was placed on a 
filter, and partially dried, so as to be easily separated from 
the paper. It was then put into a Florence flask, with a strong 
solution of pure potash, and the fluid boiled nearly to dry- 
