230 Proceedings of Philosophical Societies. {[Marcn, 
Florence flask, along with a quantity of potash ley. Being boiled 
for some time, separated by the filter, washed, and dried, it was 
fulminating platinum. 
This substance is a brown powder, varying in shade, and some- 
times being very dark, according as the circumstances are varied in 
its preparation, It is specifically lighter than fulminating gold. It 
explodes violently when heated to the temperature of 400°, which 
is also the exploding temperature of fulminating gold. It does not 
explode by trituration or percussion. It isa non-conductor of elec- 
tricity, which prevents it from exploding by the action of the gal- 
vanic battery. It indents a plate of metal when exploded on it in 
the same way as fulminating gold. When exploded between two 
plates, it acts most violently against the lower one. It dissolves in 
sulphuric acid, without giving out any gas. The solution is very 
dark coloured. Nitric and muriatic acids have but little action on 
it. Chlorine decomposes it, and converts it into muriate of am- 
monia and muriate of platinum. Ammoniacal gas has no action 
on it. When heated in muriatic acid gas, it is converted into mu- 
riate of ammonia and muriate of platinum. When exposed to the 
air, it absorbs a little moisture, but does not otherwise alter its 
properties. 
On Thursday, Feb. 13, the remainder of Mr. Edmond Davy’s 
paper on Fulminating Platinum was read. A great number of ex- 
periments were stated in order to determine the composition of ful- 
minating platinum. 100 grains of the powder contain 73°75 grains 
of platinum. When the powder is treated with nitric acid, and 
heated cautiously, there remains a grey oxide of platinum, which 
Mr. Davy considers as new, and promises to describe soon. 100 
grains of the fulminating powder left 82°5 grains of this grey oxide. 
Hence it follows that grey oxide of platinum is a compound of 
PRA UE ean since wm, srs oe Oars RSIS ae ia 
MAR VEREIL Mss iainicl o Ge stn, «dint 6 ce ote rap NL 
If it be considered as a protoxide, which is probable, it would 
indicate the weight of an atom of platinum to be 8-431. We may, 
therefore, reckon it as 8°5, without any considerable error. In 
order to determine the other constituents of fulminating platinum, 
he exploded small quantities of it in glass tubes over mercury, 
Ammonia was evolved, and water, aad a quantity of azoti¢e gas. 
From a careful comparison of the proportion of water and azotic 
gas emitted, the author concludes that the 17°5 grains wanting to 
make up 100 parts of the powder consist of 9 ammonia and 8°5 
water. According to this statement, fulminating platinum is com- 
posed of 
Giey GENS, Ve ay. Poe ee ae 
MORI UE Td. eee ey hee? Bae 
PRCT, F6 ce E MO EVV ORE 85 
