The Portland daily press. [volume] (Portland, Me.) 1862-1921, 1896-03-21
Il, 600 feet and can be loaded forty times

minute.
The series of Improvements have been
so rapid that continuous tests must DO
made to ascertain the initial velocity, the
range and the trajectory Of the missile.
When q catcher throws q baseball to
shut out a man at third base the ball
travels early on straight line, for the
distance is short and the ball is thrown
with great velocity.
But when player from deep center
field throws ball into the home plate,
the ball is thrown SO that it curves up
ward until it reaches its greatest height,
and then it drops toward homo with a
sharper curve. The line described by the
ball IN this curve Is the trajectory.
The same rule applies with rifle ball
For short distances the rife can be fred
"point blank" but as the spaoe between
| the mark and the muzzle increases the
bullet must rise in the air, else the force
ofsgrayitation will bring it to the ground
before it reaches the mark.
| Rifles, like some men, are blessed with
| foresight, and, like all men, they are
possessed of hind sights, too. This rear
sight IS long distance gauge which gives
| the proper elevation for long-distance
shooting. 1t is said that when a Spring
feld rifle is fired at a mark 5000 feet
distance the bullet rises forty three feet
above the line of sight. >
Army officers appointed to ascertain
the trajsctories of rifles go about it in
simple, scientific way. They have de-
vised 6 scheme which makes the bullet
mark its curve as it passes the space be-
tween the muzzle and the target.
For ascertaining the trajectory when
the distance is 500 yards screens are placed
foe 1,atxrz + hn via md ~.
target. In this range there are fourteen
screens, each consisting of heavy Frame
work Of timber. with a sliding sash run
ming in grooves up and down. Each sash
is covered with MANILA paper and is
raised or lowered by means of a cord.
By means of a transit the screens,
first, are accurately aligned, and Gross
pieca Is put on each one so that all of the
cross pieces are exactly on the same level
The rife is screwed rigidly in wise,
mounted on h solid support, and the
screens are lifted out of the way SO that
an unobstrneted view of the bull's-eye
can he obtained
Then tbs rifle is fred until the center
of the target is hit, and the screens then
are arranged so that those in the middle
are higher than the ones nearer the
ends. When all is ready the rifle is fred
and the bullet tips through the screens.
TIA passage can BIZ followed easily, be-
cause the "clip-clip clip" could be heard
as it strikes each paper screen. If the
bullet strikes the center of the target the
trajectory is ready to be determined.
This Is done by measuring the hight of
each bullet-hole in the screens above the
base line
For measuring the initial velocity of
rifle bullets more delicate testing meohan-
ism is required. An iron plate, in which
is a hole crossed with a fine electric wire,
| is placed directly in front of the muzzle
of the rifle, which is held in a wise. The
very instant the bullet leaves the rife it
cuts this wire and thus breaks an electric
circuit
The target 100 feet away, has light
steel spring in its back. This spring
rests upon pin, and the impact of the
bullet, striking this pin, breaks second
electric current. The two currents lead
| to the chronograph, in which two steel
rods hang from electro-magnets.
One rod Is plated with zinc, and when
| the first circuit is broken this rod drops
Tt scarcely leaves the magnet when the
second circuit is broken, and the second
rod drops A little knife in this second
rod flies open and the blade makos nick
in the zinc coat OF the first rod. That
nick likes the distance the first rod fell in
the space of time between the breaking
OF the first and the second circuits, and
tie time itself is figured from the laws
which govern falling bodies.-Chicago
Review.