The Indiana State sentinel. [volume] (Indianapolis) 1868-1895, 1880-01-14
VELOCITY OF A RIFLE BULLET.
Professor Spices Experiments at Coope,
Union.
New York Tribune.l

Professor Spices Experiments at Cooper
Union.
New York Tribunel
Professor Robert Spice, the BROOKLYN
chemist and physicist, appeared last evening
at the Cooper Institute in lecture on pro-
jectiles. The great 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 hearty well
come, and the applause was renewed when.
on the introduction of Professor RAYMOND
the lecturer came forward.
The task which Professor SPICE was 10
accomplish was to determine the actual yelo.
city of a rifle bullet fired across the stage.
The distance measured on the platform
was 80 feet; which, the lecturer ex.
planned, 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
cured the cooperation of Lieutenant K. l..
Merriam, of the Brooklyn Thirteenth regi-
| ment, who has gained some reputation at the
Creedmoor range, as evinced by the medals
which he wore. In the first place Pro-
| lessor Spice explained the apparatus to be
| used. He called the attention of the audi.
ence TO a mahogany base II inches by Is in
| ches, on which were placed two levers.
which carried bent wires to make marks on
| piece of smoked glass underneath the
| points. One of these wires was connected
with a pendulum attached to an Atwood
machine, vibrating seconds. By means of
electric currents the lever connected with
| with the pendulum came down on the glass
precisely at the beginning of each second,
| making series of lines separated by spaces
L hot civ 60 a. h. IL +
Consequently the distance from the begin
ming of one line to the beginning of the
next represented second of time
| The second lever, exactly opposite. had a
| spring attached to one end, which kept the
point off the glass. 1t had also two electro
magnets, one at each end, which had electric
currents passing through ofdifferent 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 the stronger magnet
passed through loose wire resting on two
| globules of mercury, and Immediately in
| front of this wire was to rest the muzzle of
the rifle. The weaker current passed through
precisely similar loose wire, also on two
| globules of mercury which wire was placed
80 feet distant from the first wire.
Lieutenant Merriam now came forward
and loaded the rifle. 1t was regular Creed
moor, 45 calibre 34-inch barrel, and placed
in it cartridge containing a 43O-grain ball,
and 40 grains of powder, explaining that
this was not full charge He then 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 of smoked glass was drawn
along by the descent of weight on the top
of 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 of
the corresponding lever descended on the
glass, but Immediately rose again DIV the &C
ton ola spring, when the bullet broke the
second wire. The consequence of this was
that the point connected with this lever
scraped very short line on the smoked
glass, while the other point, being kept
down during the swing of the pendulum,
seraped a longer space.
| Then the glass was withdrawn and placed
N the stereoptlcon, projecting a magnifed
image of the lines on the screen. The rela-
tive lengths of these lines were ascertained;
thus Obviating any source of error in meas
uring the minute lines on the smoked glass.
This method of measuring the lengths was
claimed to be original by the professor
On this measurement it was found that the
shorter line was FIVE inches long, and the
other line nine feet two inches. These num-
bers were brought down to the common frac-
ton of inches, the result giving 10 inches
for the longer space. 1t was then ascertain
ed how many times the former was contained
in the latter, and the fraction thus obtained
was clearly the fraction of second that the
bullet took to pass from one wire to another
that is, 1.22 of second. Multiplying the
distance between the wires (33 feet), as above,
by the denomination of the above fraction, the
velocity of the bullet in feet was obtained,
namely, 726 feet in a second.
The result was long applauded, and the
lecturer, to make things sure, determined to
repeat the experiment. The second attempt
was equally successful. Professor Spice then
proceeded to give illustrations of experiments
of the well-known magicians, showing how
science and art are resorted to to deceive the
senses. His performances and explanations
were of great interest to his hearers
L