FULMINATION. 
.78 6 
ened to the end of the shank, and the screw 
inserted to half its length into the brass cap; 
(he other end of the wire, by means of a 
needle, is to be drawn through the hole. 
The screw being now fixed in its place, and 
the wire drawn tight, is to be secured by 
pushing the irregular wooden plug into the 
aperture of the screw, taking care to leave 
a passage for the air. The stop-cock is now 
to be screwed on. The glass tube is bent, 
that it may more conveniently be introduced 
under the receiver of a pneumatic appa- 
ratus. 
“ From some of the experiments in which 
the gunpowder proof and the gun were burst, 
it might be inferred, that the astonishing force 
of the mercurial powder is to be attributed 
to the rapidity of its combustion ; and a train 
of several inches in length being consumed 
in a single flash, it is evident that its com- 
bustion must be rapid. But from other expe- 
riments it is plain that this force is restrained 
to a narrow limit, both because the block of 
wood charged with the mercurial powder was 
-more shattered than that charged with the 
gunpowder, whilst the sand surrounding it 
was least disturbed, and likewise because 
the glass globe withstood the explosion of 
ten grains of the powder iixed in its centre ; 
a charge I have twice found sufficient to de- 
stroy old pistol barrels, which were not in- 
jured by being fired when full of the best 
gunpowder. Jt also appears from the last 
experiment, that 10 grains of the powder 
produced by ignition four cubical inches 
only of air ; and it is not to be supposed 
that the generation, however rapid, of four 
cubical inches of air, will alone account for 
the described force ; neither can it be ac- 
counted for by the formation of a little water, 
which, as will hereafter be shewn, happens 
at the same moment ; the quantity formed 
from ten grains must be so trifling, that I 
cannot ascribe much force to the expansion 
of its vapour. The sudden vaporition of a 
part of the mercury seems to me a principal 
cause of this immense yet limited force ; be- 
cause its limitation may then be explained, 
as it is well known that mercury easily parts 
with caloric, and requires a temperature of 
()00 degrees of Fahrenheit, to be maintained 
in the vaporous state. That the mercury is 
really converted into vapour, by ignition of 
the powder, may be inferred from the thin 
coat of divided quicksilver, which, after the 
explosion in the glass globe, covered its in- 
terior surface ; and likewise from the quick- 
silver with which a tallow candle, or a piece 
of gold, may be evenly coated, by being held 
at a small distance from the inflamed powder. 
These facts certainly render it more than 
probable, although they do not demonstrate 
that the mercury is volatilized ; because it is 
not unlikely that many mercurial particles 
are mechanically impelled against the sur- 
face of the glass, the gold, and the tallow. 
“ As to the force of the dilated mercury, 
Mr. Baume relates a remarkable instance of 
it, as follows : 
‘ Un alclyymiste se pr6senta a Mr. Geoff- 
roy, et 1’assura qu’il avoit trouve le moyen 
de fixer le mercure par une open ation fort 
simple. It fii construire six boites rondes en 
fer fort epais, qui entroient les unes dans les 
autres: la derniere etoit assujettie par deux 
cercles de fer qui se evoisoient en angles 
droits. On avoit mis quelques livres de mer- 
cure dans la capacity de la premiere : on mit 
cet appareil dans un fourneau assez rempli 
de charbon pour faive rougir a blanc les 
boites de fer ; mais, lorsque la chaleur eut 
penetre suffisamment le mercure, les boites 
creverent, avec une telle explosion qu’il se 
fit un bruit epouvantable : des morceaux de 
boites furent lances avec taut de rapidite qu’il 
y en eut qui passerent au travel's de deux 
planchers ; d’ autres firent sur la muraille des 
effects semblables a ceux des Eclats de 
bombes.’ — Chvmie F.xperimentale et Rai- 
sonnee tom. ii. p. 393. 
“ Had the alchemist proposed to fix water 
by the same apparatus, the nest of boxes 
must, I suppose, have likewise been ruptured; 
yet it does not follow that the explosion 
would have been so tremendous: indeed, it 
is probable that it would not, for if (as Mr. 
Kirwan remarked to me) substances which 
have the greatest specific gravity have like- 
wise the greatest attraction of cohesion, the 
supposition that the vapour of water, would 
agree with a position of sir Isaac Newton, 
that those particles recede from one another 
with the greatest force, and are most dif- 
ficultly brought together, which upon contact 
cohere most strongly. 
“ Before I attempt to investigate the con- 
stituent principles of this powder, it will be 
proper to describe the process and mani- 
pulations which, from frequent trials, seem 
to be best calculated to produce it. 100 
grains, or a greater proportional quantity of 
quicksilver, (not exceeding 500 grains), are 
to be dissolved, with heat, in a measured 
ounce and a half of nitric acid. This solu- 
tion being poured cold upon two measured 
ounces of alcohol, previously introduced 
into any convenient glass vessel, a moderate 
heat is to be applied until an effervescence is 
excited. A white fume then begins to undu- 
late on the surface of the liquor; and the 
powder will be gradually precipitated, upon 
the cessation of action and re-action. The 
precipitate is to lie immediately collected on 
a filter, well washed with distilled water, 
and carefully dried in a heat not much ex- 
ceeding that of a water bath. The imme- 
diate edulcoration of the powder is material, 
because it is liable to the re-action of nitric 
acid ; and, whilst any of that acid adheres to 
it, it is very subject to the influence of light. 
Let it also' be cautiously remembered, that 
the mercurial solution is to be poured upon 
the alcohol. 
“ I have recommended quicksilver to be 
used in preference to an oxide, because it 
seems to answer equally, and is less expen- 
sive ; otherwise, not only the pure red oxide, 
but the red nitrous oxide, and turpeth, may 
be substituted ; neither does it seem essential 
to attend to the precise specific gravity of 
the acid, or the alcohol. The rectified spirit 
of wine, and the nitrous acid of commerce, 
never failed, with me, to produce a fulminat- 
ing mercury. It is indeed true, that the 
powder prepared without attention is pro- 
duced in different quantities, varieties in co- 
lour, and probably in strength. From ana- 
logy, I am disposed to think the whitest is 
the strongest ; for it is well known that the 
black precipitates of mercury approach the 
nearest to the metallic state. The variation 
in quantity is remarkable ; the smallest quan- 
tity I ever obtained from 100 grains of quick- 
silver being 120 grains, and the largest 132 
grains. Much depends on very minute cir- 
cumstances. The greatest product seems to 
be obtained when a vessel is used which con- 
denses and causes most ether to return into 
the mother liquor ; besides which, care is to 
be had in applying the requisite heat, that 
a speedy and not a violent action be effected. 
100 grains of an oxide are not so productive 
as 100 grains of quicksilver. 
“As to the colour, it seems to incline to 
black when the action of the acid of the alco- 
hol is most violent, and vice versa. 
“ I need not observe, that the gases which 
were generated during the combustion of 
the powder in the glass globe, were neces- 
sarily mixed with atmospheric air ; the fa- 
cility with which the electric fluid passes 
through a vacuum, made such a mixture un- 
avoidable. 
“ The cubical inch of gas received over 
water was not readily absorbed by it ; and, 
as it soon extinguished a taper without be- 
coming red, or being itself inflamed, barytes 
water was let up to the three cubical inches 
received over mercury, when a carbonate of 
barytes was immediately precipitated. 
“ The residue of several explosions, after 
the carbonic acid had been separated, was 
found, by the test of nitrous gas, to contain 
nitrogen or azotic gas ; which does not proceed 
from any decomposition of atmospheric air, 
because the powder may be made to explode 
under the exhausted receiver of an air-pump. 
It is therefore manifest that the gases gene- 
rated during the combustion of the fulminat- 
ing mercury, consist of carbonic acid and 
nitrogen gases. 
“ The principal re-agents which decom- 
pose the mercurial powder are the nitric, the 
sulphuric, and the muriatic acids. The nitric 
changes the whole into nitrous gas, carbonic 
acid gas, acetous acid, and nitrate of mer- 
cury- I resolved it into these different 
principles, by distilling it pneumatically with 
nitric acid: this acid, upon the application 
of heat, soon dissolved the powder, and ex- 
tricated a quantity of gas, which was lound, 
by well-known tests, to be nitrous gas mixed 
with carbonic acid gas. The distillation 
was carried on until gas no longer came 
over. The liquor of the retort was then 
mixed with the liquor collected in the re- 
ceiver, and the whole saturated with potass ; 
which precipitated the mercury in a yellow- 
ish brown powder, nearly as it would have 
done from a solution of nitrate of mercury. 
This precipitate was separated by a filter, 
and the filtrated liquor evaporated to a dry 
salt, which was washed with alcohol. A 
portion of the salt being refused by this 
menstruum, it was separated by filtration, 
and recognized, by all its properties, to be 
nitrate of potass. The alcoholic liquor was 
likewise evaporated to a dry salt, which, 
upon the effusion of a little concentrate sul- 
phuric acid, emitted acetous acid, contami- 
nated with a feeble smell of nitrous acid, ow- 
ing to the solubility of a small portion of the 
nitre in the alcohol. 
“ The sulphuric acid acts upon the pow- 
der in a remarkable manner, as has already 
been noticed. A very concentrate acid pro- 
duces an explosion neaMy at the instant of 
contact, on account, I presume, of the sud- 
