The Douglas independent. [volume] (Roseburg, Or.) 187?-1885, 1880-01-31
Velocity Of a Rifle Bullet.

chemist and physicist, appeared one
evening not long since at the Cooper In
stitute in a lecture on projectiles. The
greal hall was crowded in every part
many standing in the aisles. When the
well known face of Mr.. Cooper appeared
the audience, as usual, gave him very
hearty welcome, and the applause was
renewed when, on the introduction of
Prof Raymond, the lecturer came for
ward.
The task which Professor Spice was to
accomplish was to determine the actual
velocity of rifle bullet fired across the
stage. The distance measured on tho
platform was SO feet, which, the lecturer
explained, was shorter than usual, as the
ordinary distance used in determining
this question was about 200 feet. To
carry this performance out he had Sc
sured the co-operance of Lieutenant F.
Il. Merriam, of the Brooklyn 18th regi-
ment, who has gained some reputation
at the Creedmoor range, as evidenced by
the medals which he wore. In the first
place, Professor Spice explained the ap-
paratus to be used He called the atten-
tion of the audience to a mahogany base,
II inches by Is inches, on which were
placed two levers which carried bent
wires to make marks ON piece of smoked
glass beneath the points. One of these
was connected with pendulum attached
| to an Atwood machine, vibrating sec
onds. BY means of electric currents the
lever connected with the pendulum came
down on the glass precisely at the be-
| ginning of each second, making series
of lines separated by spaces, somewhat
similar to the old Morse alphabet. Con-
| sequently the distance from the begin
ming of one line to the beginning of
the next represented one second of
| time.
The second lever, exactly opposite, had
/ a string attached to one end which kept
the point off the glass. It also had two
electro magnets, one at each end, which
had electric currents passing through of
/ different strength-the weaker current
tending to pull the lever down on the
| glass; the stronger current tending to
keep it elevated In addition to this the
current from stronger magnet
passed through loose wire rest
| ing on the globules of mercury,
and Immediately in front of this wire was
| to rest the muzzles of the rifle. The
| weaker current passed through pre-
cisely similar loose wire, also on two
/ globules of mercury, which wire was
placed thirtythree feet distant from the
first wire.
Lieut.. Merriam now came forward and
loaded the rifle. It was regular Creed
moor 42 calibre, 34-inch barrel, and
placed in it cartridge containing 450-
grain ball, and 45 grains of powder, ex-
| planning that this was not full charge.
He took his position. The object was to
shoot away the wires on the mercury.
a box of sand was placed to receive the
BALL.
The pendulum above described was
then set in motion. On its striking the
fifth second the plate in smoked glass
was drawn along by the descent of a
weight on the top of a column of sand
which ran out of tube. On the sixth
second, Lieutenant Merriam pulled the
trigger, and both wires vanished. On
the first wire being broken, the point oi
the corresponding lever descended OF
the glass, but Immediately arose agair
by the action of spring, when the
bullet broke the second wire. The con
sequence of this was that the point con
nected with this lever scraped a very
short line on the smoked glass, with tht
other point, being kept down during the
swing of the pendulum, scraped Longer
space.
Then the glass was withdrawn and
placed in the stereoption, projecting |
magnifed image of the lines of th,
screen. The relative length of the line'
!, we're ascertained, thus obyiating an,
source of error In measuring the niinut.
! lines on the smoked glass This methot
. of measuring the lengths was claimed t,
be original by the Professor.
On this measurement ii was found tina
the shorter line was five inches long an,
the other line nine feet two inches
These numbers were brought down t
the common fraction of inches, th'
result giving i10 inches for the longe
space. 1t was then ascertained no,
many times the former was contained il
, the latter, and the fraction thus obtaine,
|, was clearly the fraction of d section tha
the bullet took to pass from one wire t
another-that is, 1-22 of second. Multi
, plying the distance between the wire
, {33 feet) as above, by the denominator Q
the above fraction, the velocity of til
bullet in feet was obtained, namely ~
feet in second.
j, The result was long applauded; an
the lecturer, to make things sure, deter
mined to repeat the experiment Th
second attempt was equally successful
Professor R.ce then proceeded to Civ
J illustrations OF experiments of the well
known magicians, showing how scienc
: and art are resorted to to receive tn
sences. His performances and explains
tions were of great interest to his heal
ers.-N T. Tribune