New-York tribune., 1896-01-08
NEW WEAPONS OF DEFENCE
PNEUMATIC DYNAMITE GUNS SUCCESS
FULLY TESTED.
THEY ARE CAPABLE OF THROWING PROJECTlLES
ABOUT THREE MILES AND FIRING FORTY
FIVE ROUNDS AN HOuR-TO BE AC-
CEPTEb BY THE GOVERNMENT.


IBY TELEGRAPH TO THE TRIBUNE.l
Washington Jan. An interesting report on the
work Of improving the countrys coast defences has
been received al the War Department. 1t relates to
the test OF three fifteeninch pneumatic dynamite
guns of 40 cabres length now in position at Fort
Winfield Scott Cal. They We're contracted for by the
Government some time ago. The trial board now re-
ports that they in place that they nave been
tested and that the country is the possessor oil
three additional important weapons of defence. AS
a result OF the trial the guns will be accepted by
the War Department. and as soon as supply OF
proectes be secured the defences OF the harbor
of San Francisco will be much stronger. The eX-
periments with the guns began early in December
and continued for a number of days, as the weather
permitted. In the course of the test eievem pro-
tectles. three charged with 800 pounds of explosive
gelatine. and eight charged with 100 pounds OF the
same and fifteen dummy projectiles Of full callpFc
and weight were fired. The projecties were fired
seaward. The explosion of one of the lW-pound
shells. impact with the water threw up COL
about 600 feet high and the ooJ-pound she'is
threw up column much higher.
The official report says that the test for the ca
pacity of the compressors OF the developed the
fact that they fully capable Of supplying air in
sufficient quantity for firing continuously forty-ive
rounds hour at extreme range. Forty -four rounds
we're actually fired in hfty-two and half minutes
At the beginning of the test the pressure per square
inch in each gun 1000 pounds. and in the storage
the the compressors had no difficulty in keep
ing this pressure in The reservoirs. the engines run
ming under eighty-seven pounds OF steam. The last
twenty rounds fired at minute intervals ami
no effort made to keep up the storage pressure
It only fell to l.7S) pounds at the hftyfourth shot
Using one gun twenty rounds-air slots-were fired
in seven and half minutes. the pressure in the
storage tanks falling from 17SO to l2o pounds the
engines working under ninety three pounds OF steam
That the loss OF air sufficient to produce ex-
treme range shown in the accuracy test in
which one gur. No. 3. with the same loss Of air
produced a range Of over 5,oc0 yards
The ,raveIsing and eevating Of the gun arc done
by electric power. and provision is made for the
accomplishment Of The work by hand II required.
The flight of the S-nch sub-oiiibre shel! charged
with lc0 pounds OF explosive steady. The fIll
calbre lj-inch shells charged with 100 pounds of
geatne were unsteady in flight. They had
gyrating motion. the tail revolving in large circle
about the line Of flight. the head in small circle.
Members Of the Board found It difficult TO observe
whether these shells always struck the water point
first. There was no failure. however 10 fire III"
fuse and explode the she'll Tho fuses used were
mechanical and set for instantaneous action
for delays OF half second or two seconds
Those set for action on impact worked az desired
Two shells were fired with fuses for two Sec
ends delay. one Of these fell at such range :hat
s delay was @ ohsersd The ohey fe at "hor, range
and delay OF exactly two seconds was noticed.
The valve mechanism OF the gun and all the work
Ing parts Of the systen acted in most salts
factory manner throughout the experiments.
rapidity Of firing ana loading. Four shells charged
with 100 pounds OF explosive Were used 10 deter
mine accuracy. The other projectiles served ior
trials for range. flight. etc Shells charged with
100 and 800 pounds OF explosive were fired for RANGE
The maximum distance attained with the ivl-pouAI
shells 500 yards about three miles, ana WIN
the tCl-pound shells 270 yards (over one milo. The
on.y test for accuracy which the limited supply ~
I projectes permitted was made with four shel.
charged with 100 pounds OF sc latne Inc shel!
attained mean range OF op5i yards: mean an l lirl's
OF 70 yards. Using the line from the piece through
the centre OF impact the line Of fire, the mean
deviation from the line was 81 yards 10 ih- left
and the lateral dispersion was y yards
A summary OF the shots fired shows ihai - per
cen, OF the shells fell within reciangc 80 by ~
by i56 feet would have contained all the hts
Two Shells with 100 popnas OF eXp9sve Js a WeTg
about 100 yards distant from the guns the sheLs
struck el feet apart 1t is OF Interest me reIor.
says. to know that the craers formed IN the sol, sGi
Sspe one case and 30 feet in diameter and feet IN
depth in the other These sheiis Terf prov,aca
for rap!dity Of !oadng and firing nye dommies
the. were hred in minutes and % seconds. the
longest interval between shots being z minutes.
The time of manoeuvrng the guns by e.cctrlc
power from extreme depression 10 extreme el"va-
tion and the reverse varied between and l3 sec
onds. The time required FOR traversing throuSn
$50 degrees by power varied between IL seconu, s
was traversei by the crew in il minutes y sec-
| onds and elevated from zero 10 % degrees In !.
seconds. and back in "a seconds Tne paliigu!a, . |.
gun tested for this purpose was the most difcult
| OF the three to traverse. Consequently the otne.
two can be manoeuvred more rapidly. although
the time given Is regarded as satisfactory