Richmond dispatch. [volume] (Richmond, Va.) 1884-1903, 1885-02-27
rgLocirY or PRoJEcrrLEs.
u,r,y 4. ssselssrs Practical TAX to New
York Electricians.
New orF IImcs'


The manner Of asccrtaining the velo-
c;tv Of proiectile was described and
illustrated nj the meeting Of the New
York Electrical Society last night by
Henry A. Sinclair, electrician at the
United States Ordnance Proving Ground
nj Sandy Hook. One Of the Bou-
lcnge monographs used at the pro-
wing ground was set up IN the
lecture-room, and Mr.. Sinclair de-
monstrated its quickness and accuracy
in determining the velocity Of pistol
ball. The instrument was described as
being very simple and very easy to
work. 1t consists of an upright brass
tube, supporting two electromagnetic,
one above the other. When test is
being made an electric wire connects
one of the magnets with the point OF
firing and another electric wire con-
meets the other magnet with the target
or objective point Of the projectile. A
long rod is suspended from the first
magnet and short rod hangs from the
second one.
The projectile in leaving the gun cuts
the first wire and the broken circuit re-
leases the long rod, which drops down
ward. When the projectile strikes the
objective point the second wire is broken
and the short rod falls, striking spring
which causes knife-blade to mark the
descending long rod. The space from
the base of the long rod to the indenta-
ton is then measured. and by the fixed
law of falling bodies the time
taken by the projectile in going
from the gun to the target is as
ccrtained, and from that the velocity
is figured. Mr.. Sinclair took good
sized revolver, loaded il with three and
half grains Of powder and a bullet
weighing SO grains. and fastened one
end of the wire attached to the first
electro.magnet across the muzzle. lie
then fred at a wired target in a tubular
shooting-gallery about four feet long.
The time of the transit Of the bullet
was determined from the mark on the
long rod, and it was speedily announced
that the velocity of the bullet was l56
feet per second. A second trial with
the same instrument showed a velocity
of POI feet per second.
Why is it desirable to ascertain the
velocity Of projectile?" asked a
member Of the Society.
Because" replied Mr.. Sinclair, - it
is means Of comparing the power OF a
gun. Of comparing different kinds of
powders and projcctiles, Of determin-
ing their energy and approximately
their range and penetration into
iron plates. Had the officer in command
of the Monitor at the time of her mem
Orablc encounter with the Mer-
rimac known what his guns would
stand he could have sent projec-
tiles clear through the iron-coyered
sides Of the ram. He used only six or
seven pounds of powder in charge
when his guns would have stood
charges of fourteen or fifteen pounds.
Few persons realize how much energy
a large projectilc possesses. \ -
inch shot weighing about 700 pounds,
and travelling with a velocity of 800
feet second, would strike as hard a
blow as railroad train consisting of a
locomotive and five or six cars weigh
ing about 100 tons moving at the rate
of ffty-seven miles an hour
Attempts were made to ascertain the
velocity Of proiectiles as early as l740,
and in 1910 electricity was first used
for that purpose. by the Schultz
chronoscope. which Mr.. Sinclair said
was the most accurate instrument of its
kind, intervals of time can be measured
from thirty seconds to one iiye-thou-
sandth part of second. Mr.. Sinclair
exhibited specimens OF the fuses used
to fire large guns. and also showed
several varieties of powder. Some of
the grains were as large as hens egg.
The method by which the pressure
excrted by an exploded charge on the
inside of the gun was measured was
The lecturer said that guns
had been tested at Sandy Hook up to a
pressure Of l07 900 pounds per square
inch. but that was extraordinary. The
average pressure on gun was about
10000 pounds to the square inch. The
velocity of proiectiles from large guns
ranged from 600 to 2,400 feet per Sc