1 4.3 Mr. Davy on a new fulminating platinum. 
that had the taste of sal ammoniac, and readily afforded 
ammonia when mixed with quicklime. The presence of am- 
monia was not only indicated by the odour, but by the instant 
production of white fumes when muriatic acid was brought 
near the mixture; and turmeric paper was immediately 
changed to brown by the ammonia disengaged. The bulb of 
the retort contained the platinum ; it was of a white colour, 
and appeared to be quite reduced. But to secure this effect, 
the bulb containing the platinum was put into a small Hessian 
crucible, and exposed to a dull red heat. The metal was then 
carefully separated from the bulb, and exposed to a full red 
heat in a platinum crucible, when it weighed 7f grains = 
7-375 grains. 
Exp. 2. Ten grains of the powder treated precisely as in 
the preceding experiment afforded 7.3 grains of platinum. 
Exp. 3. Five grains of the powder were well mixed with 
rather more than an equal bulk of flowers of sulphur. The 
mixture was exposed to a dull red heat in a small retort, and 
furnished a black sulphuret of platinum, which when decom- 
posed at a red heat in contact with the atmosphere afforded 
3. grains =3 .6875 grains of platinum. 
Now, according to these experiments, the first and third of 
which exactly agree, 100 grains of the fulminating powder 
contain 7 3.75 grains of platinum; for 10:7.375: : 100:73.75. 
Exp. 4. Ten grains of the powder were put into a small 
retort with pure nitrous acid. The acid was boiled to dry- 
ness, nitrate of ammonia was formed and yielded nitrous 
oxide gas by its decomposition. The retort after being ex- 
posed to a dull red heat contained 8.25 grains of a shining 
dark grey substance, which I have found is a pure oxide of 
