The morning call. [volume] (San Francisco [Calif.]) 1878-1895, 1890-07-13

able to assert that in air or in rock blasting
nitro-gelatine is probably from 10 to II
times as violentas powder; nitro-glycerine,
10 to 10 times dynamite. 10 to IS;
Nitro gelaline and dynamite have been
safely fired from powder guns, but some
times the result is different, as witness
Dr.. Justin's experiment at Perryville.
1t is the uncertainty OF the pressure
exerted by powder = which may vary
from one to three tons per square inch
each side Of the normal pressure-and the
apparently increased sensitiveness of dyna-
mite when it reaches the neighborhood of
so per cent of the weight of the projectile
that causes these accidents. In conse-
quence of these two difficulties it has been
of less strength and less sensitiveness in
powder guns, and we now fire successfully
wet or paraffined gun-cotton, melinite and
other explosives which, though less power
full than the nitro-glycerine compounds, are
still several hundred per cent more violent
than powder. This is very sensible
method of procedure and the use of high
explosives in powder guns Will be of great
value in many cases where the pneumatic
guns would be far less efficient or could not
be used at all.
In long powder guns, however, the guam
tty thrown in Is not more than 20 per
cent of the weight of the projectle, and in
mortars not more than 40 per cent, and
here the velocity is not greater than the
pneumatic gun would give.
In the United States Navy we use gun
cotton for our torpedoes. 1t is the most
manageable of all the high explosives. 1t
keeps well in all climates; does not give
headaches from handling like the nitro
glycerine compounds; it can be made quite
insensltiye TO shocks, and under water it
has sometimes shown as good results rs
dynamite. In peace times it is, up to the
present day, the most suitable high eX-
pl0siVe for men-of-war to carry. In war
time, however, II there is any way OF using
the more powerful explosives. that way will
surely be put in practice i'll special yes
sells, and apparently the pneumatic
system is the most plausible method for
two reasons. First, the pressure can be so
regulated as not to give too violent shock
10 the explosive While obtaining an eff
cient range; second, the percentage of eX-
pl0slye charge can be increased TO an al
most unlimited extent. At any rate over
66 per cent of charge to weight of shell has
been successfully fired. SO far there have
been no accidents, and il there should be
any we will know the pressure that was
used within very few pounds, which
would not be the case with powder.
Air is the ideal smOkeless powder; but
the point | wish to make here is that pneu-
matte guns are specially applicable to eases
where powder gun OF similar caliber
could not possibly be mounted on account
VI thC hCISit -NOhs III tIIo HlllC
boat all i've guns with their air-tankS
weigh only eight tons. A single powder
gun Of the same er-eight-inch-weighs
thirteen tons without its carriage.
think it is unfortunate that the Vesu-
vius should have been made so large, be-
eau Sc the bulk and weight of her aiT-reSer-
vOirs. guns, etc.-somethlng like 100 tons, |
belieye-make it appear as if all that weight
was in consequence of the use OF COM
pressed air instead of power, whereas it is
mainly in consequence Of the method in
which it is proposed to use it and the quau-
tty necessary to keep up an enormous fire
from her three immense guns
Nobody finds fault with a Whitehead
torpedo boat because it carries small air.
COMPRISING pump and a few air
tanks for the necessary supply of
its half dozen torpedoes They seldom
carry more than that number. aud doubt
if the Cushing will, while the Holland boat
will carry twenty aerial and twelve sUbma-
rne tUrped0eS, and yet all her weight of
fighting material will be under ten tons.
The popular objection to these guns
mounted in boat is that they will not hit
anything This will depend very much