The Democratic advocate. [volume] (Westminster, Md.) 1865-1972, 1889-05-04

vest pocket appliances which are sold to
keep ones watch from being stolen. 1t is
long rod with cone on the end, and
whenever the rod is pulled back three long
spikes shoot out from the cone and touch
the side of the gun. When they thus
come in contact with the steel the record
of evenness or inequality is registered at
the other end of the rod. When a gun
happens 10 be 365 inches long, as the ten
inch guns are, it can be seen that this
single act of star gauging is one which Oc-
cupies no little tune and labor.
Having been, therefore, subjected to all
of these tests and inspections the tube is
carried over to the foundry and there
placed muzzle upward in a deep pit ready
to await its jacket.
One need not be an expert to under
stand that the greatest force TO be resisted
Is concentrated in the rear of the gun
where the powder is fred and the shell
starts on its mission of death. SO enor-
nous are the charges now placed in a gun
that the pressure TO the squares inch in
the powder chamber is now no less than
fifteen tons. The stately Washington
Monument, mass of stone rising $50 feet
in the air, has a pressure of only FIVE tons
to the square foot, and this comparison per-
haps best illustrates the enormous force Of
the powder when converted into gas.
To withstand this shock the tube Of the
gun is strengthened BY jacket, wall Of
steel about foot aud half thick, placed
around it directly over the powder cham
Der. While the tube was being bored this
Jacket was also undergoing a similar ope~
ration. 50 that when the tube was nj last
lowered into the pit the jacket was ready
to be placed in the furnace, there heated,
and finally, after having been hovsted from
its heated bed by crane, is slipped down
upon the tube Coils of copper wire filed
with water play upon the heated band Of
metal, causing it TO shrink around the eoid
tube with an embrace destined TO last for
ever.
For DAY or longer this cooling process
Is allowed TO continue. Once more the
sube now with its steel jacket, is swung
upon a lathe, and the latter begins its tire
less revolutions, Experience has proved
that al ,hc force of the escaping projectIle
is not confined 20 the chamber from which
il starts, but that considerable pressure Is
also exerted alon. the muEEle To over
come this, steel hoops which average in
sise about four 10 the length Of the niuxzln
arc placed around the tube, being FIRST
heated and then allowed to shriak tightly
into place. This l. done. however, upon
the lathe and without = seoond visit 10 the
shrinkipg pit
What was a matter of days ia the baF
ins of the tubc besomes now PERIOD pi
wecks. a. the steel h;t Of che lathe cuts ua
long shayings Of steel from the slow rrvolv-
ing cannon. The symmetry Of the gun
now begins to appear Il aecds no label 10
identify it, Daring al the time that 1t i
up0n the lathe the ordnance inspectors
measure il carefully. compare n with the
drawings lfoE every gan has Iia working
drawings AZ detailed and a. Intricate as
these for house,, and hardly revolution
Of the lathe Is made without a test or an
Inspection. Il Is difficult to describe IN
plain words the amount of care which i
given To each one Of these deAth-deailng
crcatures. Everything that human ingc
nui,y ooulk devise and human Thought
developed is bestowed upon il.
The gun has now progressed from rough
ingol TO bored tube. which in turn has he-
eame clothed With jackets and hoops Of
steel. Once more the finest lathe runs with
careful touch through tie interior, making
the bore as polished as mirror II j. now
ready for the most important step Of al,
Right a. the entrance Of thc machine shop
stands the riiiing machine. Ga is capA-
eioas bed the cannon rests, securely iasten-
cd Into the guns circular mouth Is placed
: long bar with four sharp teeth.
For a day and half this bar revolves
within the guns interior, slowly cutting
out couple Of dozen Of twisted grooves
about a,l00 Of an inch in depth Not
many months ago each groove was cut ont
separately, aud what Is now accomplished
in seventeen hours then occupied a week.
Nowhere else in ;he world, no; even in the
famous arseaals and ordnance shops Of
the Old World, are four grooves cut at
once in rifing a cannon. so carefully,
however, is this work calculated that the
grooves come out mathematically exact tG
lhe thousandth pagt ai ap inch
The gun is now almost complete, Once
more il gees upon the lathe aud revolyes
again, while a man with big emory rubbers
/ polishes the steel until il glistens like a
streak of silver against the sombTe back
ground of the dingy shop. Previous to
this. however, the trunnion bands-the
bands which form the support for the gun
when resting in the eaTFiage--haye been
/ put in position, and ths gun is taken from
/ the shops where it has spent 80 much time
/ TO another room TO have its broeeh mechan-
/ ism perfected. IL has been critically ex.
amined By electric light aud stan. .gauged at
every point of its progress, but all the ear,
I that has been spent upon it would be a:
nought if it lacked the power to discharge
the she'll. Il is almost impossible to de
scribe in a popular way the bEeech meohan'
/ ism.
+ 1t consists, to picture it in word, of I
steel door which can be locked when th'
charge is in aud unlocked when it is out
/. Part of this door, which is probably foo
thick, consists of abestos and mutton sue
tightly compressed. When the charge i.
expanded this band, which is set between
two rims of hard steel, spreads against III,
interior of the cannon and thus cuts OF
most effectively the escape of the sas. 81
important is il that every bit Of this expan
siye gas shall be utilized that even the prim
ing hole, hardly twO.tenths of an inch II
diameter. is made self sealing, and it is es
timated that if the gas could force itsel
backward through this minute aperture the
velocity of the shell at the muzzle would b
reduced fifty feet second.
The last stages of the gun are now fas
approaching. 1t remains for 1t to b
sighted, and, simple as this operation woulC
seam to be. Lieut. Winslow, who ha
charge Of the G inch guns, says that it is
matter of six days. The utmost care
taken in leveling the gun and in makin
the sight parallel with the axis of the bore
The value of sight on rifle is known t,
every one. In the case of an immense car
, non it is no less important. Finally tn
gun is weighed to find out whether it
muzzle heavy or breeoh heavy This pre-
ponderance, as it is called, is carefully mari
II l. II, -