Evening star. [volume] (Washington, D.C.) 1854-1972, 1890-03-08

gun surrounded by . steel envelope. Between
that envelope and the muzzle OF the weapon.
however, q number of other protecting Jackets
and hoops must be put on, diminishing grad
uaily In thickness toward the muzzle in pro-
portion as the strain caused by firing diminishes
from the butt to the muzzle. The hoops and
Jackets are OF even finer steel than the tube
ltseif Tor the reason that it is easier to make q
thin piece OF steel frst-rate in quality than a
large mass OF metal Every part of the gun
!nat Is put on the tube is secured by the heat
ing and cooling process except the trunnions,
on which the cannon rests when equipped with
Its carriage. These trunnIors are placed as
near the center Of gravity of the gun as posi-
Bile and so accurately are they adjusted with
this end in view that there is often difference
OF only 10 or II pounds between the part in
front and the part behind. so that child can
raise or depress the muzzle of a cannon weigh
ing many thousand pounds by the effort of
one hand.
IN THE GUN SHOP.
1t is marvellous thing to see the way in
which the great cranes in the gun shops oper-
ate. lifting swiftly the heaviest masses of metal
from any part of the buildings and transferring
them, under the direction of the engineers, to
any other part. In making new cannon the
various portions must be carried hither and
thither and to and fro many times before the
gun is finally got together. Accordingly the
hosting and carrying mechanism is constantly
at work 1t presents, indeed, the most not
able feature of the machinery in the gun shop.
As you enter the big gun shop at the navy yard
where the boring and jacketng described are
performed you find yourself in vast building
something like an exposition hall, enormously
long, very high, and sky-lighted. On either
side for the entire length of the building runs
line OF tall iron supports holding up sort of
something that looks like bridge, extending
at height Of perhaps twenty-five feet, almost
the whole width of the structure. II you will
imagine an elevated road upheld by two paral-
lei lines of posts 60 feet apart and with track
the same width you will have feeble notion
to begin with. The car that runs
on these two rails. as it were, 60 feet
apart, is the bridgelike continuance aforemen-
toned, and this car is made to run from one
end OF the shop to the other by means of a re-
volving shaft extending the length of the build
ing. Thus the hosting mechanism on the car
bridge can carry anything that it can lift
lengthwise OF the shop. But, in order to take
up weighty object from any place and put it
down in any other given spot, the hosting
machinery must also be able to move sideways,
and this is just what is very ingeniously pro-
vided for by making the hosting mechanism
run from side to side on rails upon the bridge.
the long shaft referred to doing the whole
business, including the lifting. Such is the
crane and its operation in the big gun-making
shops at the navy yard. 1t can only lift As
tOus, out one tndG mas DeeQ OrQGreQ the
same shop and which will be set in operation
this spring is to be o. 10 tons capacity, and
will be the largest crane ever used in the
United States.
RIFLINa THE CANNON.
Now, so far the cannon is merely jacketed
tube. A further boring process is next gone
through to rifle tin other words. to cut on
the inside of the tube those spiral grooves which
give the projectlle a rotary motion as it leaves
the muzzle of the gun. Very little now re-
mains but to polish off the gun with files
smoothing the edges of the jackets down from
square to round, every part of the weapon in
its various diameters from muzzle to breech
having been reduced in the lathe to precisely
the size required by the specification. Finally
the plug, which closes up the breech and is OPP
Grated almost instantaneously by crank so as
to shut the cannon Theoretically when it Is to be
fired, is attached and the instrument of de-
struction has only to be sighted" before it is
finished and ready to go out of the shop. This
operation of sighting Is one of some difficulty
and requires the greatest care, for allowance
must be made for the curve of the projectile.
MOUNTING THE GUN.
So much for the gun itself. But it is not
ready for action until it has been mounted.
And this necessity is provided for by another
vast shop close by the one already described
and almost equally big, which is devoted to the
manufacture of gun carriages. The most I'M
proved type OF gun carriage made nowadays,
as to the lower part of it, termed the slide"
is turned out in a single iron casting and sent
to the navy yard by the manufacturer in that
crude shape. The carriage proper, which runs
on the grooves of the slide is constructed of brass
at the shop, furnishing sort OF cradle for the
gun to rest in, balanced on its trunnions. Also
In this shop, which has an enormous crane like
that In the gun snop spoken of, the arc-shaped
tracks are made for the mounted guns to re-
%hxd aa Of 81
may be pointed toward the horizon in any d.
rection desired.
TESTING ITS MERITS.
But the gun is not mounted on its carriage
at the navy yard. 1t goes first to the proving
grounds at Annapolis, where the ten shots
required by law are fired to test its quality,
with full charges of powder. Surprising that
it is found satisfactory it is very likely sent di-
rect from the proving grounds to the vessel
that wants it. As for the carriage, it is stored
at the navy yard until requisition is made for it,
third big shop at the yard is largely gwen
up to the manufacture of conical projectiles
some Of cast iron others of cast steel and others
still of forged steel. Nearly all of them are
loaded with few pounds of quick-burning
powder, which is exploded upon the arrival of
the projectile at it's destination, either by fuse
or by cap.
WORKOUT GUNS.
What wears out gun under ordinary cir
cumstances is the scoring of the polished in
side of the rifed barrel by the particles of gun
powder. Once a few scratches made, other
such particles score them deeper and the
weapon is weakened and injured. Some day
before long it Is intended to take one of the
new guns from the navy yard to the proving
grounds and destroy it by firing in order to
find out what its resistance is. When a gun has
been incapacitated for further service in this
ordinary way it is often rebored, making its
callber little larger and making new inside
surface for the barrel with fresh rifing Then
1t Is ready for further work. If gun is to be
pulled to pieces the jackets have to be sliced
through and wrenched off by powerful ma
chinery. When gun is thus destroyed at the
yard the men all scramble for the steel to turn
1t to use tor their tools it is 80 ordinarily
fine.
IN LOADING THE GUN FOR USE
the plug is first pulled open from behind and
the conical projectile is showed in SO that it
rests just forward of the powder chamber, a
copper ring about its rear end resting in
groove just at the division between the rihed
barrel and the powder chamber itself, which of
course occupies the breech. The projectile, if
of the best type, is pointed with steel so hard
that a file will not cut it. This enables it to
penetrate the object hit. Around the sides,
however, its steel envelope concealing the
powder with which it is loaded is more soft
for the reason that if the huge bullet were of
very hard steel all over it would be too brittle
and would smash up on striking such mark
as steel armor. So the projectile lies in the
barrel, which it fills up, Immediately forward
of the powder chamber, into which is thrust a