National Republican. (Washington City (D.C.)) 1872-1888, 1885-12-05

iNAh ilkt ihINt DTtknt ltitNfoptS WIFI nnfhA
extended, only the sighting Is done at tho
large end. We lind the tube spoken OF
nlOut tbree-fourths covered with its
"jaCkep aud ringsw which enclrclo the tube,
making II largest at the breech and small
est toward tho muzzle. These are so closely
fitted on that one would at frat think
the whole gun was one solid piece OF metal.
The uninitieted can have the mystory Of the
clcse joints explained by leaving the en-
ishod guns ard going over IN the ordnance
foundry again and see. the process of ''as-
scmlliDg,n or Of shrinking the jacket and
rings on the tube. The first piece to go on
the tube is the Jacket which covers the
htCch Of the tube to the extent of ono
third Of The entire length, which tube is ct
first as simple in its form as blow pipe.
They VIII bo found standing on the ground
on end.
JAoKETINe THE TUBE.
IL will be something like to S feet hirh
by 4 feet outside diameter Beside this
jacket from six to nine rings go on each
gun. IL the tube is about TO be "jacketed,"
as It Is called-that is, placed in position
on the tube-a wood fire will be found TO
be luining both on the inside and outside
Of the jacket and q mIchinist will be on
hand, and every short time will measure
the inner diameter TO see when II has been
expanded by the heat sufficiently TO 90
over the tube, and this is the way IN which
the mystery Of the close joints Ia cleared.
The "inckets" inner diameter is made
about 2-1CC0 Of an inch less than the outside
diameter Of the tube over which II Ia TO pasS,
and can only be passed on by this method OF
expanding the metal by heat
When IL is known that tube Is TO ba
''jacketed," large party is always on
band to witness the operation, which for
the wde-eyed wonder watcher is the most
interCs sting OF all the processes, as II ncces-
states the lifting and swinging around of
immense pieces of metal, weighing thou
sands of pounds.
FOREMAN DAVIS EXPLAINS.
While the preparatory work Ia going on,
| M. j. d. Davis, the efficient foreman, will
| likely explain something about the philoso-
| ply OF putting these rings on the tube TO
| form the gun. OF course they are TO give
strength, and we at once understand that II
the tube should crack, the rings, covering
nearly the entire length, would tend to pre-
vent an immediate explosion.
SHRINKING THE TUBE.
When II is announced that the ''jacketn
has expanded sufficiently derrick Is
swung around, and soon the piece is raised
| and carried around TO whore the tube is
stationed, firmly fixed In an upright posi-
ton, standing in pit SO as to bring its top
about level with the ground. Over this
| the Jacket" is lowered, so simply that the
| fact OF the close measurements are forgotten
| by the idle lookeron. The "jacket"
| gradually cools, and contracting, clasps the
| tube as one piece, The reason for the abso-
lutte precision necessary in fitting the jacket
on the tube is apparent Too great shrink
age, which would be the case II the jacket
were too small, would strain the metal, and
| too little would prevent the metal from hay
ing tighthold. The contraction of the metal
| forms close contact, and gives constant
| pressure upon the tube. After this the
rings are shrunk on In the same way over
the Jacket and also on the tube from
where the "Jaeketp ends toward the muzzle
| The rings are about 1 to 2 feet long, and
add TO $ inches to the entire diameter Of
the gun. This pressure OF the jacket and
rings contracts the bore Of the tube very
noticeably.
REMOVING A JACKET.
| II will sometimes, though seldom, happen
that a jacket has to be removed from its
tube, which gives another interesting sight.
| To do this the gun is arranged In an upright
| position, with the jacket end down, SO that
molten iron may be poured into mould
around the jacket, giving 1t an expansion
sufficient to draw 1t out. The main point In
| this process is to raise the tube from its
| jacket as soon as 1t is loosened, as during a
short delay the tube would expand proper
tionately, which, OF course, would prevent
| its withdrawal.
| ThE GUN.
After the gun is assembled IL is smooth
bored and riiled by the usual Methods
and the next step is to proceed to the
breech-loading apparatus, where the mech
| anism connected with the gun Is situated.
| The breech closure, which is known as the
slotted screw system, is also an American
idea, being originated by Mr.. Benjamin
Chambers, formerly of Washington. The
late Admiral Farragut tested 1t In 1851, and,
with notifications, IL was adopted by the
navy and hfterward by the army, and
has become popular with, and is used
by, European gun manufacturers. The
slotted screw is an arrangement for gripping
the plug securely in the breech Of a gun
after loading. Sections Of screw threads
are arranged on the inside Of the breech
alternately with ''slots" or blank sections
of equal width, so that the corresponding
screw and slot sections on the plug may
allow IL to be showed In the breech, the
screw sections OF the plug occupying the
slot or blank sections OF the breech. This
plug is then given turn, which locks the
screw threads together. II is then fastened
so that shock cannot loosen Its hold
LOCKING THE DREEcH.
The original invention OF Mr.. Chambers
was arranged with only two pAlys of thread
sections alternating with slotS'bn the inside
| OF the breech and on the plug. This, OF
course necessitated turning the plug around
one quarter its circumference to lock its
screws with those on the inside of the
breech. This long swing was exceedingly
inconvenient, and is now remedled In the
| present arrangement by having the screws
| and slots insertions Of one-sixth the circum-
ference Of the plug.
After we examine the arrangement for
locking the breech when the charge placed
inside ready for firing, 1t must not be for
gotten to look inside the powder chamber.
This is several per cent. In excess Of the
| diameter Of the bore. 1t thus enables
larger charge of powder to be used than
| was dreamed of in times past. The power
| of a gun depends largely upon the size of
its powder chamber, though its length must
be sufficient to allow the combustion of the
entire charge.
| THE RANGE OF THE BIG RIFLES.
After examining the breech closure, as it
| is when finished, we find ourselves standing
before the completed gun, and its capable
| ties become the subject for discussion. An
inquiry as to the distance the gun will fire
will get us the answer that rough estimate
| Of the range of high-power gun is given
| by saying that II will send a shot one mile
for each inch of caliber the gun has. This
| gives the lO-inch q range OF ten miles.
THE EFFECTIVE POWER OF GUN.
1t is not the size of caliber, however, that
| gives power 10 the gun, Tor the Two lO-lnch
| guns manufactured at the navy yard, which
weigh about twenty-five tons each, will ex-
coed In total penetrating power, as well as
range of projectile, the old-fashioned thirty
eight ton l2l-inch rihed English gun made
at Woolwich up to 1881. But the American
10-inch gun is s feet longer than the one
above referred to, and this Increased length, 1t
must be noticed, is one of the chief charac-
teristlcs OF high-power guns. The velocity OF
the English 12l-inch shot has attained to
1000 feet per second, while the Amerl-
can 10-inch, 1t is calculated, will give
its proioctile velocity of 2,100 feet
per second. This makes It necessary for