JMiscellanies. 187 
**M. Descotils, the discoverer of this variety of fulminating silver, 
_ says (Ann. de Chim. Vol. LXII, p. 198, and Nicholson’s Journal, 
Vol. XVIII, p. 141,) that ‘a blow or long continued friction causes it 
to inflame, with a brisk detonation. Pressure alone, if it be not very 
powerful, has no effect upon it.’ I can account for this erroneous 
statement, so dangerous to young operators, and which has been ever 
since copied into some of the most respectable treatises, only by sup- 
posing that the powder might have contained a mixture of the nitrate, 
precipitated by the alcohol in consequence of its seizing the water of 
the solution, (which sometimes happens also in preparing, the fulmina- 
ting mercury,) or that the precipitate was not dry; .2t is quate certain, 
that the fulminating silver, when properly prepared and dry, will 
bear neither pressure nor friction, and very little even when wet.” 
“Tt is well known that careful drying greatly increases the sen- 
sibility of the fulminating powders, and their violence when exploded. 
My own practice has long been, never to keep either the fulmina- 
ting mercury or silver in a vial,* whose explosion, especially when 
held in the hand, must of course occasion injury. It is perfectly 
safe, to place the powder in small quantities, in little paste board ca- 
ses covered by a loose card; when moved, they should never be laid 
in the palm of the hand, but always taken up, by applying the thumb 
and finger to the edge of the card box; a few grains at a time may 
then be jarred out, upon a card for use, and in this manner no acci- 
dent will ever occur. But in pouring from a vial, the mere impetus 
of falling, may, by the weight alone, cause fulminating silver to ex- 
plode. I have always found, that when this powder is perfectly dry, 
it will rarely bear the weight of a common sized hammer, cau- 
tiously allowed to press upon it-by degrees, and without any blow; 
and, if sand be previously mixed with the powder, on the anvil, the 
hammer can scarcely touch the mixture ever so gently, without caus- 
ing a detonation. 
Too much caution cannot be used in the management of fulmina- 
ting silver, and no considerable quantity of it should be kept on 
hand, unless in small divided parcels, and in paper boxes as above 
described.— Ed. 
* IT was present in Dr. Woodhouse’s laboratory in Philadelphia, thirty years ago, « 
when a vial of fulminating mercury exploded, spontaneously, while standing on the 
table, and from no obvious cause unless it was the jarring, produced by the assem- 
bling of the class for the lecture. 
