The Savannah morning news., 1901-11-19
TESTING of BIG GUNS.
Minute observations Made at the
Proving Grounds.

From the New York Post.
The government ordnance proving
ground at Sandy Hook is busy and
thunderingly noisy place just at this
season of the year, and every week
thousands of dollars worth OF armor-
plate, projectiles, and powder are util-
lied in demonstrating thai this coun-
try possesses the best guns, the best
steel armor, and the most efficient ex-
plosives in the world. 1t seems almost
l. wanton waste OF material to heave a
ponderous S EEL shell or armor- piercing
projectile, which is the product of the
finest machinery against steel plate
which has required the work of many
men and years of experimenting TO
bring it to its perfection and submit
it to demolition.
But governments are proverbially
prodigal when 1t comes to testing these
offensive and defensive weapons. their
subs titutes for wooden walls" it
would indeed be niggardly to count the
cost of even half dozen armor plates,
several hundred pounds of powder,
and dozen or more steel shot and
weigh il against the millions represent
ed in a battleship, to say nothing or
the lives OF four hundred men and the
dignity of the nations flag.
Time was when the tesung of gun
was, viewed in present lights, Slip
shod, unsatisfactory sort OF process
Much was taken for granted after the
piece had demonstrated its ability to
hold together during the strain of dis
charge There were few of the nice
ties" of gun-test. But now the proving
of a gun is as careful and inethodical
an operation as the testing of a watch.
Not only must 1t hold together, but 1t
| must demonstrate its intention to hold
4 H.. 4
use it must show Itself capable of Civ
ing the projectiles a high velocity, a
comparatively fat trajectory and be as
good a gun afterward as it was when
| II left the lathe and the pit. Il
Velocity is the thing, for that means
range and penetration. The seacoast-
defense guns, which stand to guard
| the country against the invasion OF a
naval force, are designed to hurl shells
filled with high explosives against an
! enemy's ships, to penetrate their arm
! or or vulnerable parts, and, through
, delayed action of the shell fuse, to blow
them "out of the water"
| So, after gun has behaved properly
| with powder, the test for velocity is
| imposed, and this brings into use an
| instrument which performs its task
| with an accuracy which is simply as
1 founding. 1t is used to measure the
| velocity of the projectile and is called
| a chronograph. 1t depends upon the
| fundamental law of gravitation and is
at once simple and complicated. The
! principle is certainly simple.
In a general way the chronograph
consists Of powerful magnet, steel
rod, and a knife blade. These three
parts, with others naturally related to
them, are mounted in a structure set
at considerable distance from the EN-
placement upon which the gun to be
! tested is mounted. This is to obviate
Earring when the pieces is discharged.
At the top Of the machine is the pow
erful magnet which. when the current
is closed, holds the rod suspended as
an armature. The rod hangs over an
| aperture in the base of the instrument.
and at one edge of this opening a knife
blade is placed and held back against
spring by another electro magnet.
The brick found alton upon which the
instrument is built goes many feet into
the ground in order that the greatest
/ stability may be obtained.
To return to the gun, two square
| frames are erected on the line of fire,
the first one hundred yards from the
/ muzzle Of the gun. and the frames ex-
actly one hundred yards apart Back
and forth across these frames is a net
! work of wires, rather a cross-weaving
OF one wire which runs from the frame
to the instrument in the distant house.
/ and is connected with the electro mag
] net which holds the slender steel rod.
! The second screen is like the first, save
that It's wire runs to the second electro
magnet, the one holding back the knife
blade at the base OF the chronograph.
Then. with the current on, the rod
, suspended, the knife blade res -rafned
| against the spring, the gun is fired.
! The projectile pierces the first screen,
the wire is broken. the circuit Is open
! ed, the magnate is demagnetized in
stantly and the rod drops. The projee- .
| tile speeds across the hundred yard
/ space and pierces the second screen.
breaking its wires and breaking the
electric circuit. This releases the
knife-blade, past which the rod must
fall, and, energized by the spring, the
blade flies forward and strikes the rod.
making minute nick upon it. BY
this time the projectile has flown into
the great sand butt and buried itself
and the nickel steel rod has dropped
into sand-filled receptacle. The We
locity has been denoted by the utili-
cation Of a simple law.
1t is known that a falling body falls
1914 feet the first second. SO feet the
second, and so on in this ratio until
it reaches earth. Applying this prin-
ciple to the rod, It is known that its
foot was exactly at the level of the
blade, so that by measuring the dis
lance from the foot to the nick, gives
the space through which the rod has
fallen. Then, remembering the gravity
law, that a body falls 1914 feet the first
second, It is readily determined how
long the shot has required to cover
the 100 yards between the screens. This
gives practically the initial velocity of
the projectile.
Peace has it's tests of a sailors or a
cn.ldlnr,n h,.nntnr.rr M Inrn ror,arn thar.