The record-union., 1898-04-12

tions it is stated that the English Gov
ernment tested the safety of gun cot
| ton by burning bonfires in two lots of
a ton each. In one case the explosive
| was in disks in a closed tank and in
| the other it was divided among eighty
closed packages. In both cases the gun
cotton burned away without exploding
In order to explode moist gun cotton
| a special kind of primer or detonator
must be used, consisting of a disk of
dry gun cotton, and this dry gun cot
| ton is exploded by a illuminate of
mercury fuse fired by electricity These
disks Of guncotton may be made any
| size. Usually they are about four inches
in diameter and an inch thick, with a
hole in the center Several disks of
wet gun cotton are placed one over the
other; near the top is put one layer
or disk of dry cotton, then the cleo
trio primer is lowered into the charge
| through the hole, and the entire cart
ridge is carefully sealed up with a
watertight head through which the
electric wires lead, which are to be
spliced to the wires leading to the
firing battery. 1t is of the utmost i'm
portance to keep this dry guncotton
dry. Should it get wet the fuse would
be imperative. When gun cotton is
used to charge the war heads of tor
pedoes, the cotton is usually nodded
| to fit the form of the chamber de-
signed to hold it.
NITRO Ugly COMPOUNDS.
Gun cotton is not so extensively used
for commercial submarine operations
as some of the nitro-glycerine COM
pounds, mainly because of the difficult
ty of preparing it for firing. Nor is it
so terrible in its explosive action as
some of them. A form of gelatine seems
to be more generally preferred. One
of these now on the market is called
Repauno gelatine. 1t is described as a
high explosive powder, having a gela-
tine consistency 1t is, therefore sticky
and very dense or heavy-two very ad-
vantageous features in certain classes
of work. The higher grades have eX-
traordinary disruptive power. 1t is de-
cidedly plastic This, with it's density,
renders it particularly suitable for sub
marine work, where the flow of water
is strong, because it will adhere firmly
together even should the covering of
the charges get damaged or removed,
and it is not disintegrated by water
Another high explosive in our mar
ket is forcite. 1t closely resembles ex-
plosive gelatine cellulose, being used
instead of nitro -cellulose. Some forcite
contains % per cent. of nitro glycerine,
and other grades less, incorporated with
mixture of nitrate of soda, SULPHUR
and wood tar with a little wood pulp
| added. 1t burns in the open air. ex-
plodes in confined places, and water
has no action on it.
| RELATIVE STRENGTH OF HIGH
EXPLOSIVES.
There are many other explosives
suitable for submarine use some of
them of a greater explosive strength
than dynamite, others less. Some years
ago General Abbot of the United States
army carefully investigated the proper
ties of several kinds of high explosives
and gave as the results of his expert
| ments the following relative strengths
under water of certain ones of them
per pound, assuming dynamite No /,
that described above, as 100: Blasting
gelatine, wet 81; nitro glycerine, 81
guncotton, wet, 81; gun powder, 20 to
90. There were some other interesting
data reported by General Abbot con-
corning high explosives. His expert
ments led him to believe that in order
to wound the bottom of a man-of war
of 5000 tons, armOred with nine inches
of iron, an explosive must produce a
pressure of $500 pounds per square
inch; that $500 pounds would be fatal
! to an ordinary double bottomed iron
clad. However all scientific investiga-
tors in this direction, as we'll as in other
/ theoretical matters pertaining to the
force which high explosives exert, are
not by any means in agreement. Re-
| ferring to some of the results of the
researches of Colonel Bucknill of Eng
land into the relative strengths of high
explosives, it is noticed that he gives
the following relative horizontal dis
tances and charges necessary to inflict
a fatal blow on modern ironclad: