The San Francisco call. [volume] (San Francisco [Calif.]) 1895-1913, 1895-09-23

miles are not so imposing, complicated or
striking in appearance nor SO costly and
terribly effective.
Three of these guns are to stand close
together on the brow of one of the highest
bluffs that overlook the Golden Gate and
the ocean between Fort Point and Bakers
Beach. AS stated, two are in position and
the third is rapidly being put together.
San Francisco will soon possess three of
the eight dynamite guns in the world.
Three have been set up at Sandy Hook,
one is still on the Nictheroy of the Brazil
ian navy and the other one was two or
three years ago sold to the English Gov
eminent and set up at Shoreburyness.
These three guns and the alr-compress-
ing plant will cost the Government 500, 900
when the Pneumatic Torpedo Construction
Company of New York turns them over in
working order. Protecting parapets and
other things will cost many thousands
more, so that at least quarter of a million
dollars will be invested within a less space
than that covered by the Mills building.
They are the most ponderous looking
engines OF war ever constructed, and the
most ingenious and powerful ones. Each
gun as ii stands in its revolving base, with
out it's accessories below and behind,
weighs 43 tons. They stand on great turn
tables sunk four feet into the massive con-
crete beds about them, and the gun bar
rels of massive steel, with 15-inch bores,
stretch 81 feet through the air. The &C.
companying cut gives but general idea
OF their external appearance, but when
one sees and understands the internal
machinery, the delicate adjustments of
massive things, the ease with which the
43-ton machines are handled, and their
surprising accuracy, they seem quite won
derful.
Around each turntable, several feet in
diameter, is finely graduated brass scale
by which the gun can be ranged Literally
with great precision, and the gun can be
pointed in any direction. A telescope
sight and level help to give the elevation.
The gun can be depressed one degree be-
low the level and elevated 80 degrees. The
gun is entirely handled and fired by one
man who stands on a little platform be-
side the guns axis, and two little levers
and one wheel control the movements and
firing of the gun. These movements are
adjusted machinery inside the queer-look-
ing carriage.
In big concrete-protected cellars and cor
ridors below ground are the compressed
air reservoirs directly connected with the
gun. There are eight firing reservoirs be-
low each gun and connected with it. These
reservoirs are great tubes, holding alto
gether, when charged, 800 cubic feet of air
after compression to pressure of 1000
pounds to the square inch. The opening of
valves around the cham Der of the gun al the
base lets this pressure in behind the cart
ridge, which, with diameter of Is inches,
receives pressure of LIE, 900 pounds as it is
elected.
Even as striking and imposing is the
great air COMPRISING plant which is
housed in a brick building about 200 feet
behind the three guns. This plant has
Just been completed by the Fulton Iron
Works. Four great boilers give 400 horse
power. and forced draught arrangement
will add 200 horse power more.
In the engine-room two enormous du-
pick engines and air-compressors stand
pumps are directly connected with the
engine cylinders and the two duplex COM
pressors appear at first to be four great
engines about forty feet long. In opera
ton each compressor squeezes the air
three times. In one cylinder it gets
pressure of rs pounds. In the next it is
com pressed to 400 pounds, and then it is
jammed up so hard in the third one that
its pressure becomes 1000 pounds. This
heats the air so highly that it is taken at
once through coils OF copper tubing below
the floor and immersed in water to be
cooled off. It then reaches twenty-four
storage reservoirs in another room. These
are long tubes about foot in diameter,
and in operation the pressure il them is
valves and large underground pipes these
storage reservoirs supply the firing reser-
voirs below the guns. There is an electric
plant and many other features which
make the whole thing appear complicated
and costly.
a supply of dynamite cartridges is due,
but day before yesterday there were only
dummy cartridges ready for use The
projectiles for the use of this costly
plant, built to destroy any hostile ships
that might be reckless enough to get within
two or three miles OF the Golden Gate, are
very imposing and complicated things
themselves. They are several feet long
and have vanes on shaft behind then,
like the feathers on an arrow. Each shell
may be loaded with 500 pounds of dyna-
mite, and what 500 pounds of dynamite
might do may be guessed. When so loaded
the shell would weigh 116O pounds. They
are ingeniously contrived and contain fuses
which would variously be fired by impact
against water or solid body. These shells
cost from $500 to $500 each.
The accuracy of fire of these guns has
at past tests been marvel to EXPERTS in