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mind of the Phenomena I observed lately, when the powder-mill and maga¬ 
zine at Hackney blew up ; for besides the very great noise of the blow which 
I heard, being within a mile of it, in the fields, I observed immediately, a 
great white cloud of smoke to rise in a body to a great height in the air, and 
to be carried by the wind for two miles and better without dispersing or fall¬ 
ing down, but perfectly resembling the white summer clouds : but this only 
by the bye. From these Phenomena of the earthquake it seems very pro¬ 
bable, that it proceeded from such subterraneous inkindling as resembles 
gunpowder, both by the noise it yielded, and in the suddenness of its firing, 
and its powerful expansion when fired; for the noise was as of many cannon ; 
this alone proves it to be very sudden. 
“ Next the splitting of the rocky island proves its power to be very great \ 
this is proved yet farther by the blow and strokes it communicated to the sea^ 
and so to the ships that sailed upon it ; for no slow motion whatever could 
have communicated such a concussion through the water to the vessels upon 
it; but it must be as sudden as that of powder, otherwise the stroke of the 
earth upon the incumbent seas, would never have had the like success ; for 
if it had been a gradual rising of the bottom, the sea would gradually have run 
off from it, and upon its sinking again have gradually returned, and the vessels 
on it would only have been sensible at most but of a current or running of 
the water to or from the place sinking or rising, somewhat like the effect that 
happened at Nevis ; which doth plainly shew, that, besides the sudden strokes 
riatic acid, which are the true solvents of gold. This solution yields yellow crystals, resembling to¬ 
pazes, in truncated octahedra, these crystals being a true muriate of gold. It tinges animal sub¬ 
stances purple, and by‘distillation, yields a red liquor, called by the adepts, the red lion. An oxide 
of gold is precipitated from this solution, in a yellow powder, nearly in a metallic state, by lime, 
magnesia, and by alkalies ; the precipitate being soluble in the sulphuric, nitric, and muriatic acids. 
When precipitated by ammoniac from the yellow solution, it is called fulminating gold, it de¬ 
tonating when gently heated. Fulminating gold has been proved to be a mixture of ammoniac, and 
oxide of gold ; the oxygen of the latter, and the hydrogen of the alkali taking tire by simple heat, de¬ 
tonate; and the gold is restored to its metallic state. 
Nitriated silver, being precipitated from its solution, separated from the fluid, exposed three days to 
the air and light, and mixed with liquid ammoniac, becomes, when dry, fulminating silver. This 
exceeds in power, gunpowder, and even fulminating gold. Once obtained, it can no longer be touched 
without a violent detonation, no more than one grain being sufficient to give rise to a dangerous fulrni- 
nation; after this fulmination, the silver is found reduced or revivified, its oxygen having combined 
with the hydrogen of the ammoniac, by which water, in the state of vapour, is produced. Ibis water, 
instantly vaporized, and possessing all the elasticity, and expansive force of that state, is the principal 
cause of the phenomenon; in which the nitrogen of the ammoniac, with its whole expansibility, bears 
a part. Vide an excellent Compendium of Chemistry by the ingenious James Parkinson, surgeon. 
