144 Mr. Davy on a new fulminating platinum. 
of it was dispersed, but there was a slight effect with the 
appearance of red light. 
Fulminating platinum is tasteless, and insoluble in water. 
It is not affected by this fluid at any temperature. When 
exposed to air in a dry state it acquires a little moisture, but 
this effect is very limited. Twenty-two grains when well 
dried at a temperature of about 21 2°, and made to expose 
a large surface to the atmosphere for two days, gained half a 
grain, but there was no farther increase on exposing the 
powder for two days longer, and when gradually heated to 
the temperature at which it had been dried, it weighed 
twenty-two -grains, as at first. 
I have not ascertained the specific gravity of the powder, 
but from the greater apparent bulk of an equal weight of it, 
as compared with that of fulminating gold, I conceive its 
specific gravity is less than this last substance. 
Fulminating platinum is soluble in cold sulphuric acid, but 
much more readily so by the assistance of heat. The solu- 
tion is of a dark red brown colour. It is less soluble in mu- 
riatic and nitrous than in sulphuric acid. There seemed to 
be a slight spontaneous action, and a disengagement of gas, 
when each of the above acids was brought in contact with 
the fulminating powder. At first, I thought carbonic acid 
might exist in the powder, and the manner in which it was 
prepared, did not necessarily preclude the presence of that 
substance. To ascertain if this were the case, or whether 
any gas were disengaged by the agency of an acid, I put 
two grains of the powder in a cubic inch, filled it with mer- 
cury, and inverted it over a mercurial trough ; half a cubic 
