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EXPLOSIVES 
.The History and Development 
By "A.M.I.C.E," 
MODERN fighting, both on land and sea, depends 
primarily on explosives, either for blowing up 
trenches, buildings, railways, etc., or for 
propelling projectiles and bullets. A modern 
war without explosives would be inconceivable. 
.\n explosion may be defined as a very rapid combustion 
evolving gases which are considerably expanded by the heat 
produced by the combustion. 
Explosives may be classified into three groups : (i) 
Propelling explosives, (2) Disruptive explosives, and (3) 
Detonators or exploders. A propellant is an explosive having 
a rate of combustion regulated to a certain extent between 
time limits, while in a detonator or disruptive explosive the 
disturbance lasts only a very short time. An explosion can 
take place in two ways, either by burning or detonation. 
In the first case the flame from the e.xploding charge is 
quickly communicated to all the exposed surfaces of the 
powder, while in the second case the initial force of the 
explosion is sufl5cient to break down the structure of the 
powder, so that the flame reaches every particle of the mass ; 
thus causing an instantaneous ignition, which is called 
detonation. Detonators are useless as propeUants, since the 
force is generated so quickly that it destroys substances in 
contact with it instead of projecting them to a distance. 
The first group includes all classes of gunpowder and 
smokeless powders used in fire-arms ; to the second group 
belongs all explosives used in shells, torpedoes, mines, 
demolitions, etc., and to the third group belongs those used 
for originating explosive reactions in the explosives of the 
first two groups. Gunpowder consists of three substances, 
namely, saltpetre, charcoal, and sulphur, and differs from 
other explosives by being a mechanical mixture, and not a 
chemical compound. 
English black gunjxjwder for military use is composed 
of seventy-five parts of saltpetre, fifteen parts of charcoal, 
and ten parts of sulphur. The ingredients are intimately 
mixed together and are inert towards one another until the 
application of heat causes them to combine chemically. 
Charcoal and sulphur are both combustible bodies requiring 
only a sufficient amount of oxygen to combine with in order 
to be converted into gaseous products. Saltpetre (or 
potassium nitrate) is very rich in oxygen, which is released 
by the application of heat, and combines with the sulphur 
and charcoal, which burn rapidly. For warlike purposes 
gunpowder has become a negligible quantity, although it is 
still employed to a certain extent for blasting and demolition 
purposes. It is not used to any extent for propelling bullets 
or projectiles, as there are better compositions available, but 
it is still used to a certain extent in ordinary sporting rifles. 
France was the first country to adopt a smokeless powder 
— in 1885, for use with the Lebel magazine rifle. It was 
invented by VieUle, and was known as Vieille powder or 
" Powder B " — so named after General Boulanger. Since 
that date many preparations giving Uttle or no smoke were 
proposed as a substitution for gunpowder, the principal 
ingredient being gun-cotton. In 1888 Mr. Alfred Nobel, the 
inventor of dynamite, took out a patent .''>i the combination 
of nitro-glycerine with gun-cotton for the production of a 
smokeless explosive. Modern smokeless powders can be 
divided into those that are made of nitro-cellulose (the 
chemical name for gun-cotton) and those that are made of 
nitro-cellulose and nitro-glycerine. 
Gun-cotton, which is to-day the principal ingredient of 
modern Service powders, was discovered in 1846 by Schonbein, 
and was proposed as a substitute for gunpowder. Pure gun- 
cotton belongs, however, to the explosives of group 2, and 
by itself is totally unsuitable for use as a propellant. It is 
largely used for demolitions, submarine mines, and torpedoes. 
It is prepared by immersing cotton wool in strong nitric acid 
and then carefully washing it. The cotton, which contains 
principally carbon, corresponds to the charcoal in gunpowtler, 
and the nitric acid, which is very rich in oxygen, to the 
saltpetre. 
Modern gun-cotton or nitro-cellulose is prepared by 
using the waste of cotton mills and subjecting it to a pre- 
liminary purification to free it from dirt and grit. Cellulose 
is one of the most widely distributed plant constituents — 
llax, hemp, and cotton consist chiefly of cellulose. The 
purified cellulose is then placed in stoves, and carefully dried 
and heated with a mixture consisting of highly concentrated 
nitric and sulphuric acids. After nitration it is carefully 
washed in water, and is then reduced to a very fine state of 
division in a " beating machine." After being boiled by 
means of steam and another thorough washing it is ready to 
be moulded. If not required for immediate use gun-cotton 
is generally stored wet. Wet gun-cotton is often used instead 
of dry, but in the wet state it is not so easily detonated. 
IS'itro-ceUulose Service powders are made by mixing 
gun-cotton with ether-alcohol or ether-acetone, by which 
process the fibrous character of the gun-cotton is more or 
less destroyed. A material is thus produced of which the 
rate of combustion is slower than the original, and is, there- 
fore, suitable as a propellant. After treatment the mixture 
is pressed or roUed, and is then cut into a suitable form. 
PropeUants of the nitro-cellulose t5rpe are used by France, 
Russia, U.S.A., Germany (army only), and Austria (army 
only). 
Nitro-glycerine was invented by Sobrero in 1847, and is 
produced by the action of nitric and sulphuric acids on 
glycerine. Pure nitro-glycerine is a colourless oily liquid, 
but is often of a slight yellow tint. It explodes when heated 
to about 360° Fahrenheit. A drop of nitro-glycerine explodes 
when struck with a hammer on an anvil, and it is very 
sensitive to percussion. Nitro-glycerine in the liquid form is 
too dangerous to be used in practice, but Nobel discovered 
in 1867 that when nitro-glycerine was absorbed by a porous 
solid it could be used with comparative safety. This 
explosive is known as dynamite. The porous material 
generally employed for absorbing the nitro-glycerine is 
" kieselguhr," which is a special kind of earth consisting of 
the shells of minute diatoms, and is found in some parts of 
Germany and in the north of Scotland. Dynamite usually 
contains twenty-five parts of kieselguhr and seventy-five 
parts of nitro-glycerine. 
The first nitro-glycerine-nitro-cellulose powder was 
invented by -Nobel in 1888, and called ballistite. The 
principal ingredients are gun-cotton and nitro-glycerine, 
whUe camphor is employed as an agent for promoting the 
union of the two explosives. As camphor does not remain a 
constant ingredient, and thus leads to chemical alterations, 
the use of camphor was discarded and aniline or vaseline 
added. Ballistite is the Service powder in Italy, and is 
much used for large guns. It was the first successful smoke- 
less powder. The English Service powder used in the Army 
and Navy is cordite, and was the outcome of the investiga- 
tions of the Explosives Committee, of which Sir Frederick 
Abel, the chairman, carried out a long series of exhaustive 
experiments. 
It consists of 58 per cent, nitro-glycerine, 37 per cent, 
gun-cotton, and 5 per cent, of vaseline. It is known by the 
name of cordite, owing to the cord-like form it assumes 
during nianufacture. As gun-cotton is not soluble in nitro- 
glycerine, the mixture cannot be gelatinised without some 
medium, and for this purpose acetone is used. The gun- 
cotton and nitro-glycerine are mixed together in the right 
pr9portions, and acetone is added and hardened in the mass. 
After about three and a half hours the correct quantity of 
vaseline is added to the mixture and the whole thoroughly 
mixed. It is then passed through hydraulic presses and 
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