266 Professor Davy’s account of 
a filter, washed and dried, either in the open air or at a heat not exceeding 212° Faht. 
its properties appear to be the same. 
The new fulminating silver, in drying on the filter, breaks into small lumps, which 
are easily separated from the paper, and reduced by the gentle pressure of a platina 
spatula, or of a card, to an impalpable powder. Its colour, when recently prepared, 
is white ; and if dried in the dark, or in a weak light, it retains this colour for some 
time. On being exposed to a strong light or the sun’s rays in a moist state, it soon 
undergoes progressive changes of colour ; from greyish white to yellowish brown, brick 
red, blackish brown, and even black. These changes are facilitated by the presence 
of water, and they appear to be connected with the partial decomposition of the com- 
pound ; for on exposing a little of it in water for some time to the action of the solar 
rays, I observed, by means of a magnifying glass, minute specks of metallic silver on 
the surface of the water, apparently carried there by small globules of gas, which were 
occasionally evolved from the compound. 
The new fulminating silver, when heated to about 350° Faht. assumes a darkish 
tint and explodes, producing a large yellowish flame, and a loud report. It also ex- 
plodes by percussion, when struck with a hammer on an anvil ; and by friction, when 
it is rubbed between two hard surfaces; hence, it must be handled with caution. 
It is insoluble, or very nearly so, in cold water. I tried in vain to dissolve a single 
grain of the dry compound in about eleven fluid ounces of pure water ; after some 
days, the greater part was undissolyed. The water, however, became slightly turbid, 
acquired a metallic taste, and on evaporating some of it to dryness, a very minute por- 
tion of the compound remained. Boiling water dissolves a certain limited quantity 
of the compound; but as the fluid cools, the greater part separates in minute crystals, 
which are principally long needles, intersecting each other. 
The new fulminating silver, in a dry state and even whilst it yet retains moisture, 
instantly explodes when brought in contact with pure chlorine gas; and also when 
this gas is mixed with most other gases, as will be presently stated. 
Muriatic acid decomposes the new fulminating silver, readily, converting it into 
chloride of silver, whilst hydrocyanic acid is evolved; and if the experiment is 
continued to dryness, sal-ammoniac rises in vapour, and the pure chloride of silver 
remains. 
Strong nitric acid gradually decomposes the new fulminating silver with evolution 
of gas ; but if diluted, fulminic acid is slowly disengaged, and nitrate of silver formed. 
Strong sulphuric acid readily explodes the new compound ; but when diluted, the 
fulminic acid is gradually evolved, and sulphate of silver produced. 
The new compound is soluble, to a certain extent, in liquid ammonia, and as the 
alkali evaporates, minute crystals are deposited, which explode by heat, but not in 
chlorine gas. Solutions of the fixed alkalies dissolve a portion of the new compound, 
and form crystallized fulminating compounds, which I have not examined. 
