The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1898-08-07
HOW 1T AFFECTS THE BODY.
Firing a Big Gun Brings About Many
Physical Changes.
Philadelphia Times.

Philadelphia Times.
Not one man in ten thousand has clear
idea of just what happens when big can
non is fired The physical manifestations
are numerous. Even professors of chemistry
and physics are stumped when they want to
Cifferentiate all the gases set loose and the
peculiar effects they induce. The puff of
whitish smoke, the flash of fire. the dim
image of the flying projectile, the roar and
the recoil are all familiar; but back Of these
is a complex mass of phenomena most be-
wildering to the mind of any but an artil-
lery expert.
First the cubes, disks, heXagons or irreg-
ular Jumps of powder are chemically trans
formed into a powerful, expanding gas the
instant firing takes place. Then there are
innumerable by-products that even chem
lists do not understand.
The explosion of gunpowder is divided
into three distinct stages, called the igni-
ton, inflammation and combustion. The ig-
milton is the setting on fire of the first grain,
while the Inflammation is the spreading of
the flame over the surface of the powder
from the point of ignition Combustion is
the burning up of each grain. The value of
gunpowder is due to the fact that when sub
jected to sufficient heat it becomes a gas
which expands with frightful rapidity The
so-called explosion that takes place when
match is touched to gunpowder is merely a
chemical change, during which there is
sudden evolution of gases from the original
solid.
1t has been calculated that ordinary gun
powder on exploding expands about nine
thousand times, or fills a space this much
larger as gas than when in a solid form.
When this chemical change takes place in
closed vessel the expansion may be made
to do a work like that of forcing a pro-
jectile along the bore of the great gun or
test tube in the line of least resistance
The hardest work a gunner is called upon
to do is to stand the tremendous shock.
The forces eXerted by these gases in ex-
from the cannon, as ripples are caused by
dropping a pebble in a pool of still water.
AS a matter of fact, it has been discovered
that these lines of forces are exceedingly
complicated affairs and play very queer
pranks about the cannon. AS result few
people know just which is the safest or the
most dangerous position for a gunner to
take beside his gum In the case of the
ton back of the gun is much easier than
one nearer the muzzle.
mense pressure eXerted on the sides of the
cannon so that another distinct series of
shocks also radiate outward from the barrel
of the gun. These lines of force are in
fuenced, besides, by the recoil of the gun,
which tends to make the lines curve out
ward and intensitieS the shock. These are
in turn more less compensated by the
forces of the air opposing them as 1t ruSheS
into the mouth of the cannon when the pro-
iectile leaves it. AS a result of all these
forces the atmosphere is, of course, violently
disturbed. Although no projectile strikes
the gunner. who must stand by, it will be
seen that the air is full of missiles in the
form of invisible lines of force or vibrations
which lombard, as it were. every part of
the gunner'S body at the same time.
An examina ton and analysis of the effect
produced upon the human system and the
mind by the firing of cannon is most en-
glC SSinE. Men generally accounted cOurag-
eous trembe violently in their knees: others
feel nauseated; some have severe headaches /;
few have had their ear drums split or the
action of their heart affected.
Take the vital organ, the heart, first In
the space between the right auricle and
ventricle are a set of fine. threadlike cords
them tremble like timbers in a building
when there is an earthquake. In weak
man the chamber of the heart is left open
for an instant; the opening, and closing
springs lose their controls the heart shakes;
possibly the chordae tendineae are snapped
contraction or dilation of the organ ensues
and in some instances death follows.
Deafness induced by an explosion may be
traced to the sudden pressure upon the in
ner orifice of the ear and the tremendous
vibration set up. The thin. transparent
fairly bright membrane called the drum of
the ear is burst. like piece of tissue paper
held taut and forcibly blown upon. Sounds
are conveyed by the beating of tiny mall
let upon this anvil If the beating is too
amid and too forcible, the membranes may
be rl.ptured, a temporary disturbance of the
mind occurs and the sufferer becomes dizzy
When the knees tremble 1t is due to the
nervous shock produced in the cerebellum
All the nerves and muscles are thrown into
atomic contractions and relaxation and the
knees appear TO give way.
Nausea is also caused by the physiological
change that takes place in the brain.
There is a pressure of blood there, and the
stomach, responding, tries to empty itself
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