The Democratic advocate. [volume] (Westminster, Md.) 1865-1972, 1878-06-01

A ne tube IS now ready to receive the
first layer Of hoops. For these large steel
ingots are cast and forged into peculiar
shape. These have holes near either end.
which are Joined by slot. Wedges are
driven into the slot, and it is gradually
widened out and worked under hammer
into ring-like shape. This has at this
stage of the operation about half the di-
ameter aud twice the thickness of the
finished hoop. 1t is then heated and put
over the rolls of a machine similar to that
used in the manufacture of wheel tires.
In revolving the rolls approach each other
gradually, rolling the hoop to its desired
size. BY this operation it will be seen
that an endless fiber is being developed in
the direction of the hoop circumference
A jet of water is constantly playing over
the steel mass while it is being developed
on the rolls, thus preventing any distor-
tion. 1t is stated that in this way hoops
of any required diameter can be procured,
but not of width exceeding 6 inches
These hoops so manufactured have, like
the large tube ingots, no seams or YIELDS,
and are very uniform in texture Every
thing being ready for the hopping, the
main tube is placed, muzzle end up, in
vertical position, aud the hoops slipped on
to their places. The hoops are previously
heated in boiling lead, and, when the ex-
pans;on is judged sufficient, are taken
out Of the bath, wiped clean, slung to
above the muzzle in line with their in
tended positions and let go. They fall
heavily along down the tube until they
reach their position. Here they cool
slowly, and contracting, form a perfect
contact with the tube. The hoop manu-
facture aud subsequent adjustment are very
delicate operations. The calculations in
volyed are very nice, as the diameter of
the hoops as first manufactured, has so to
be calculated that after the expansion in
the bath and subsequent cooling, they
will, on contracting, have diameter which
will cause them to exert certain pressure,
to be the same 10 all of the same layer,
upon main tube and upon each other when
superimposed. 1t is necessary, for in
stance, that the second layer should exert
a greater pressure upon the first and inner
tube than the first does on the main tube
of the gun. 1t will be seen, therefore,
that the shrinking on of hoops is an ope-
ration requiring much care and skill.
Upon the successful performance of the
hopping depends the guns strength and
durability. The first layer of hoops hav-
ing been placed in position, the gun is
again taken to the turning establishment,
and the surface of the first layer which is
to receive the second turned down to the
required diameter The second and third
layer being in place, the gun again goes to
the turning establishment. The hoops
are kept from working by key rings, these
being small half hoops, with rectangular
sections let into scores cut to receive them
in the tube and first layer and in the first
and second layers. The breech of the
gun is then shaped, the bore carefully
rihed, and the eccentric chamber formed.
The closing mechanism at the brcech is
adjusted and the gun is finished
The manufacture of 14-inch gun takes
about sixteen months, and they are worth
some 100000 apiece.
zCcN RAINS Va OA0hahNC JCS e.
hihited by the firm, and which has been
since sold to the Russian government, is
the 14-inch, SOL ton, long iacketed and
hooped, breech-loading ca steel rifed
gun, which was the most prominent object
in Herr Krupps display at the Philadel-
phia Exhibition. This gun carries steel
shell weighing 1,l24l pounds, using a
charge of 245l pounds. The length of
the tube is 261 feet, aud the length of the
bore 22l feet. The twist has length Of
52A feet, and is uniform. There are so
rife grooves, having depth of 1-12 inch
each and breadth of lands 3-16 inch
The closing Of breech is effected by
what is known as the cylindro-prismatical
wedge. This slides into horizontal NOR
tise of the same shape, let into the breech
piece. The plug is, like the gun, of steel,
and the wedge and the cylinder form one
body. The wedge is drawn out on the
left side. The rounded part is at the rear,
that side giving greater bearing surface,
while the front side is fat and forms the
bottom or end of the bore. The breech
plug is moved in and out by transport
ing screw turned by crank, it being kept
in position during the operation by leading
lasts, which work in small grooves let into
the top and bottom and cut parallel to the
after edge. The closing of the interior
aperture left by the wedge and the pre-
vention Of the escape of gas breechward is
effected by plate and circular ring. The
ring is a steel circle fitting into the groove,
close to the wedge aperture, at the bottom
of the bore. This is supplemented by a
plate which is circular and slightly hol-
lowed out, and which is entered on to the
wedge, which is cut for this purpose in
front, in order that when the breech is
closed, its slightly projecting rim shall
meet the ring which similarly projects over
the front side of the wedge hole The
vent is axial, passing through the breech
block, and is fitted with copper-lined,
cylindrical steel vent tube.
The projectiles used for this gun are
steel, chilled, and fuse shells. These are
guided in the groves by pair of copper
rings, the one at the front end Of the pro-
jectile being used for imparting a rotary
AHUliOu W suOl. SLcGi StGilS usS0
weigh, without their bursting charge,
109l27 pounds, the chilled shells 1140
. pounds, and the fuse shells S3S pounds,
the weight of The bursting charge for the
first is 33.07 pounds; for the second, H.
64 pounds. The powder used is that known
as prismatical, having a specific gravity of
from l.73 to 1.76. For steel and chilled
shots the normal charge is 242l pounds,
and for the fuse shells 275 pounds. These
charges are calculated to give the follow
ing initial velocities For the chilled
shells 154l4 feet; for the lighter steel
shells 1903 feet; and for the fuse shell
1923 feet per second.
Planetary Population.
On the interesting question of the plur-