National Republican., 1886-08-19

over thl9 tue Jacket" is lowered, so slim
ply that the fact OF the close measurements
are forgotten by the idle looker-on. The
"Jacket' gradually cools, and contracting,
clasps the tube as one piece. The reason
Tor the absolute precision necessary in ft-
ting the Jacket on the tube is apparent
Too great shriukage, which would be the
case II the Jacket were too small, would
strain the metal, and too little would pre-
vent the metal from having a tight hold,
Inc contraction OF the metal forms close
contact, and gives a constant pressure
upon the tube After this the rings are
shrunk on In the same way, over the
Jacbet," and also on the tube from where
the Jacket" ends toward the muzzle. The
rings are about one to two feet long, and
add six to eight inches 10 the entire diam
eter OF the gun. The pressure OF the Jacket
and rings contract the bore OF the tube very
noticeably.
, It will sometimes, though seldom, happen
That Jacket has TO be removed from It's
tube, which gives another interesting sight.
To do this the gun is arranged in an up
right position, with the Jacket end down,
go that molten iron may be poured into
mold around the jacket, giving IL an ex-
pansion sufficient TO draw it out. The
main point in this process is TO raise the
tube from It's jacket as soon as II is loosened,
as during q short delay the tube would ex-
would prevent Its withdrawal.
After the gun Is assembled IL is smooth
bored and ri1ed by the usual methods, and
the next step is to proceed TO the breech-
loading apparatus, where the mechanism
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 It In 1851, aud,
with notifications, IL was adopted by the
navy and afterward by the army, and has
become popular with, andsis used by, Eu-
ropean gun manufacturers. The slotted
screw Is an arrangement for gripping the
plug securely In the breech of gun after
loading. Sections Of screw threads are
arranged on the inside Of the breech alter
nately with "slotsn or blank sections Of
equal width, so that the corresponding
screw and slot sections on the plug may
allow 1t 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 a turn, which locks the
screw threadstogether. 1t Is then fastened
o thtt q shock cannot Loosen It's hold.
The original invention Of MIR. Chambers
was arranged with only two rows OF thread
sections alternating with slots on 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 remedied In the
present arrangement by having the screws
ind slots In sections OF one.slxth the cir
Gun ference OF the plug.
The powder chamber 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 gun depends largely upon
the size OF Its powder chamber, though its
length must be sufficient to allow the COM
bustion OF the entire charge.
The penetrating power Of the great guns,
as well as the range, Is the subject OF many
inquiries. A rough estimate Is formed by
the rule that q high. power gun win send a
shot one mile for each inch Of caliber. This
gives the 10-inch gun q range OF ten miles.
II is not the size OF caliber, however, that
gives power to the gun, for the two 10-inch
guns manufactured at the navy yard, which
weigh about twenty-five tons each, will ex-
ceed In total penetrating power, as well as
range Of projectile, the old fashioned thirty
eight ton 129-inch rifed English gun made
OF Woolwich up to 1881. But the American
10inch gun is 8 feet longer than the one
above referred to, and this increased length,
1t must be noticed, is one of the chief char
acterlstlcs OF high-power guns. The velocity
OF the English 121 inch shot has attained
to 1900 feet per second, while the Ameri-
can 10.inch, II is calculated, will give its
projectile velocity Of 2,100 feet per second.
This makes 1t necessary for the American
10-inch to stand a strain In excess OF the
English 12i-inch, which weighs third
more. This is possible because the tensile
strength OF the steel In the American gun
is 10000 pounds to the square inch, while
the English gun, consisting Of common
steel tube hooped with wrought iron coils,
has tensile strength Of only $4,000 or
10000 pounds to the square inch.
This comparison shows the advance In the
manufacture OF guns, and not the superiority
OF American guns over the English, because
1t must be remembered that the English
have large numbers Of high-power guns and
are pressing their manufacture.
The length and weight of the guns,
weight Of projectiles, and charges are as
follows:
Ten-inch, length 273 feet, weight 81, 900
pounds, weight Of projectile 500 pounds,
powder $50 pounds: Sinch, length 81 feet,
weight 27,500 pounds, weight OF proiectlle
$50 pounds, powder 1876 pounds; 6-inch,
length 16 feet, weight II 900 pounds, weight
OF projectile 100 pounds, powder so pounds;
5-inch, length ID feet, weight $500 pounds.
The guns will be distributed among the
cruisers by ordering two OF the S-inch TO the
Boston and two to the Atlanta. The 6.inch
guns will be divided between the Atlanta
and Boston, and the 5-inch will go to the
Chicago, as also four s-lnch and eight 9.
inch.
A number Of the 6.inch, 5.inch, and one
S-inch gun have been completed, the latter
having been just tested at the Annapolis
proving grounds with the most favorable
results: The 10-inch guns are well pro-
gressed.
The length Of time required to build one
OF the modern steel guns at the navy yard
is six months, but on account of delays In
receiving material no gun has been built
there in that time.
The gun carriage also is an object OF
much interest, as II requires as much inge-
nuity In it's construction as the guns them
selves. They are arranged so that the
weight OF the gun is equally distributed, and
can be moved In any direction with greatest
facility. The carriages are marvels of
mechanism in their simplicity. Then there
Is the apparatus for raising the charge and
the projectile to the breech when loading.
The powder which will be used for the
great guns Of the Atlanta has been ordered
from the Rhenish Westphalian Company,
but the powder for the Boston and Chicago
can be made In the United States.
Reviewing the progress and success of
the American gunmakers but one conclu-
sion can be reached, and that is that In this
respect America has taken her usual place
L. .Al LII "a