The Sun.
London, England, 1870-05-17 00:00:00

GUNPOWDER v. GUN COTTON.

On Saturday a number of experiments were perforined
by the officers of the Royal Engineers at Chatham to test
the comparative effects of gunpowder and guncotton in
various operations. A large number of distinguished
officers assisted at this remarkable trial of strength. The ex-
periments commenced with explosions of gunpowder and
guncotton directed against a double stockade of balks of
timber, l4in. square, 3ft. 6in. apart, and sunk 3ft. in the earth
each line braced together by strong cross-pieces. A charge
of 2001 b. of gunpowder, in bags, merely laid at the foot of
the stockade, untamped, was first exploded. It forced a
large gap in the front stockade, but, though partially
shattered, the second row of timber would have presented
a formidable obstacle to an attacking party if defended by
a few resolute men. Portions of the timber were burled
through the air to some distance. A charge of 801 b. of
guncotton was next laid in bags at the foot of the stockade,
some distance from the former explosion. This also
was untouched. It was fired by a detonating fuse. There
was a terrific explosion, and an almost perfectly clear
breach was made through both rows of timber, practically
for an attacking party to get through. The effect was
very much superior to that of the 2001 b. of gunpowder.
Immense pieces of timber were hurled through the air to
a great distance, mostly in the rear of the stockade.
Not so wide an extent of timber appeared to be
shaken as by the first explosion, but the work
was more completely done ; the results, indeed,
were extraordinary. Experiments were then made in
another part of the field by exploding discs of guncotton
against single balks of timber, to shew what effect would
be produced if timber bridges had to be destroyed. Four
balks of timber, about sixteen inches square, were sunk in
the ground some feet apart, in a square, and braced toge-
ther by thick pieces of plank. A. " necklace "of small
discs of guncotton was formed, 68-i in number ; this was
doubled and placed half round one of the timbers. The ex-
plosion of this string of discs tore away the wood for some
depth, four inches or more, on one side of the balk, but did not
break it, though the massive timber was much rent. Three
or four larger discs were then exploded on one side of the
timber, and tore out a large portion of the wood. A single
" necklace " of small discs, sixty-five in number, and
weighing 211b.' was then placed round another balk, quite
encircling it. When exploded this tore out the wood all
round to some depth. Then twelve of the larger discs,
weighing 41b. 20z., were hung on nails on three sides of the
timber, and exploded. The explosion was very powerful,
and the large balk was cut in two—snapped off where the
gun cotton had been attached, but falling on the side
where there had been no discs and partially splitting on
that side, The spectators cheered at this decisive proof
of the value of gun cotton for this special purpose. All
these experiments appeared to be very satisfactory. At
that part of the lines in front of St. Mary's Barracks, a
number of mines and galleries had been excavated and
charged with gunpowder or guncotton. One mine had a
charge of 5001 b. of gunpowder ; a second similar mine was
charged with 2001 b. of gun cotton. Two smaller mines
were charged respectively with 21.61 b. of gunpowder and
8.61 b. of guncotton. These mines were successively exploded
by means of an electric current. In the larger mines the
powder appeared to be the most effective agent. In the 1
explosion of the 200 lb. charge of guncotton a peculiar effect
was produced ; first, there was the eruption of brown
clay and smoke, and then a large flame, produced by the
ignition of the gaseous products of the explosion. The
officers then proceeded to the old Engineer Depot near St.
Mary's Convict Prison, and walls which are to be
removed were experimented upon ; they are 18 inches
thick ; charges of guncotton ranging from 21b. to
311 b. were exploded against these walls with satisfactory
results, making breeches in them. The officers then re-
turned to the scene of the mines, where two long galleries
had been prepared, one charged with 2401 b. of gunpowder,
the other with 961bs. of guncotton. These charges were
exploded. The object was to ascertain if it is practicable
to form trenches in this manner, instead of throwing them
up while exposed to the enemy. It was thought by some
officers that the explosion would throw the earth up on
either side in such a manner as to form a trench ; but the
result was not so—the earth was thrown up in a mass, and
no trench was formed in which men could get under cover
at once.