with
melinite, is used for charging shells. By neutralising a boiling saturated
solution of tri-nitro-cresol with ammonia, a double salt of ammonium and
nitro-cresol crystallises out upon cooling, which is similar to ammonium
picrate. This salt is known as "Ecrasite," and has been used in Austria
for charging shells. It is a bright yellow solid, greasy to the touch,
melts at 100 deg. C., is unaffected by moisture, heat, or cold, ignites when
brought into contact with an incandescent body or open flame, burning
harmlessly away unless strongly confined, and is insensitive to friction
or concussion. It is claimed to possess double the strength of dynamite,
and requires a special detonator (not less than 2 grms. of fulminate) to
provoke its full force. Notwithstanding the excellent properties
attributed to this explosive, Lieut. W. Walke ("Lectures on Explosives,"
p. 181) says, "Several imperfectly explained and unexpected explosions
have occurred in loading shells with this substance, and have prevented
its general adoption up to the present time."

~The Fulminates.~--The fulminates are salts of fulminic acid,
C_{2}N_{2}O_{2}H_{2}. Their constitution is not very well understood. Dr
E. Divers, F.R.S., and Mr Kawakita (_Chem. Soc. Jour._, 1884, pp. 13-19),
give the formulae of mercury and silver fulminates as

OC = N AgOC = N
/ | \ | \
Hg | O and | O
\ | / | /
-C = N AgC = N

whereas Dr H.E. Armstrong, F.R.S., would prefer to write the formula of
fulminic acid

ON.C.OH.
|
C(N.OH),

and A.F. Holleman (_Berichte_, v. xxvi., p. 1403), assigns to mercury
fulminate the formula

C:N.O
Hg | |
C:N.O,

and R. Schol (_Ber._, v. xxiii., p. 3505),

C:NO
|| Hg.
C:NO

They are very generally regarded as iso-nitroso compounds.

The principal compound of fulminic acid is the mercury salt commonly known
as fulminating mercury. It is prepared by dissolving mercury in nitric
acid, and then adding alcohol to the solution, 1 part of mercury and 12
parts of nitric acid of specific gravity 1.36, and 5-1/2 parts of 90 per
cent. alcohol being used. As soon as the mixture is in violent reaction, 6
parts more of alcohol are added slowly to moderate the action. At first
the mixture blackens from the separation of mercury, but this soon
vanishes, and is succeeded by crystalline flocks of mercury fulminate
which fall to the bottom of the