The evening times., 1899-06-03
A NEW EXPLOSIVE.
The Latest Filling for Shells a Form
of Picric Acid.
(From Chambers JournaIl

From Chambers Journal)
Probably one of the most interesting
features of the Omdurman campaign. from
| a military standpoint. was the great sue
cess achieved by the lyddite shells, which,
used for the first time in actual warfare
by the British army. proved that lyddits Is
the best explosive as yet discovered for
use in shells. 1t is the object of the pres
ent article to give a short description OF
this substance which is destined to play
an important part in the wars of the fu-
ture.
Lyddite is only variety of picric acid
which has been melted and allowed to So
lidify, thereby becoming denser. Melinite
recently introduced into the French army,
is also another form of picric acid; indeed
most of the so-called new" explosives
consist Of this substance in one or another
of its forms, disguised by different names.
The history of picric acid as an explosive
is remarkable and furnishes striking ex-
ample of how great discoveries may fire.
quently result from accident Picric acid
was discovered in iii, and for more than
century was used as dye for WOOL silk
and leather, without its explosive powers
being suspected. Some ten years ago. how
ever. a fire occurred at chemical works
in Manchester, and spread to shed con-
tanning a quantity of this acid. Bsing
melted by the heat, the acid flo we'd
until 1t came in contact with a quantity OF
litharge stored in the same building. A
terrible explosion followed, and subsequent
investigation revealed the fact that under
certain conditions picric acid behaved as
a powerful explosive. Further experiments
have made clear the necessary conditions
and at the present time picric acid bids
fair to outrival all other explosives for
the purpose of filling shells.
Before proceeding to describe the man
ner in which this body is caused to liber-
ate its explosive power it will be advisable
to give a brief account of its manufacture
and common properties, in order that the
sequence may be made clear. Pure phenol,
or carbolic acid (the common disinfectant
obtain from coal tar) is placed In vessel
with an equal amount of strong vitriol
(sulphuric acid), and the temperature
raised to the boiling point of water. Strong
nitric acid (aQuafortis) is then allowed to
flow into the mixture, after which the
whole is cooled. leaving a solid mass of
yellow crystals in the vessel These crys-
tails are filtered and drained, and after
ward washed with cold water, and the res
idue is pure picric acid.
The crystals SO obtained have an intense
ly bitter taste, and for this reason have
been largely employed on the continent for
the adulteration Of beer. II handled, pic
ric acid stains the fingers a golden yellow
II heated gently it melts quite TRANQUILITY,
and may be poured from one vessel to an
other. II strongly heated it chars with
sill hit fzzle; II hammered on an anvil no
occurs, as in the case of most
explosives. A cursory examination, such
as the foregoing, gives no indication of its
latent powers. and 1t Is therefore a mat
ter of little wonder that they should have
remained undiscovered for more than
century.
The shock necessary to explode picric
acid In all its forms 10 furnished by class
Of bodies known a. ''detonators." These
are sensitive bodies which explode With
great violence; and II placed in contact
with large mass Of picric acid the shock
to which their explosion gives rise causes
the whole charge to detonate, an extreme
y small quantity of the detonator sumo
Ing to set into action an indefinitely large
quantity Of the acid.