Evening star. [volume] (Washington, D.C.) 1854-1972, 1898-06-25
HOW 1T AFFECTS THE BODY.
Firing Big Gun Brings About Many
Physical Changes.

S"unSSSs
From the 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 chemis-
try and physics are stumped when they
want to differentiate 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 bewildering to the mind of any but
an artillery expert.
First. the cubes, disks. hexagons or ir-
regular Jumps of powder are chemically
transformed into a powerful. expanding gas
the instant firing takes place. Then there
are innumerable by-products that even
chemists do not understand.
The explosion Of gunpowder is divided into
three distinct stages. called the ignition,
Inflammation and combustion The ignition
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
subjected 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 d chemical change, during which
there is a 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 a gas than when in a solid form.
When this chemical change takes place in
a closed vessel the expansion may be made
to do a work like that of forcing a projec-
tile along the bore of the great gun or test
The hardest work a gunner is called upon
to do is to stand the tremendous shock
The forces exerted by these gases in ex-
panding seem to radiate in all directions
from the cannon as ripples are caused by
dropping pebble in a pool of still water
AS matter of fact, it has been discovered
that these lines of forces are exceedingly
complicated affairs and play very queer
FRANKS about the cannon. As a result few
people know just which is the safest or the
most dangerous position for gunner to
take beside his gun. In the case of the
great 13-inch guns on our monitors, a posi-
ton back of the gun is much easier than
one nearer the muzzle.
In addition to this force there is an i'm
mense pressure exerted on the sides of the
cannon SO that another distinct series of
rel OF the gun. These lines of force are
lnfuenced, besides, by the recoil of the gun
winch tends to make the lines curve out
ward and intensif1es the shock. These are
forces of the air opposing them as 1t rushes
into the mouth Of the cannon when the pro-
jectile leaves it. AS result of all these
forces the atmosphere is. of course, vio-
lently 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 1t were every
part of the gunner's body at the same time.
An examination and analysis Of the effect
produced upon the human system and the
mind by the firing of cannon is most en-
crossing. Men generally accounted cour-
ageous tremble 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 set of fine, thread-like cords
called the tendineae. The conclusion makes
them tremble like timbers In a building
when there is an earthquake In q weak
man the chamber of the heart is left open
for an instant; the opening and closing
springs lose their control; the heart shakes:
possibly the chordae tendineae are snap
ped: contraction dilation of the organ
ensueS and in some instances death fol
lows.
Deafness induced by an explosion may be
traced to the sudden pressure upon the in
ner orifice of the ear and the tremendous
fairly bright membrane called the drum of
the ear is burst, like piece Of tissue paper
held taut and forciby blown upon. Sounds
are conveyed by the beating of a tiny mall
let upon this anvil. II the beating is too
rapid and too forcible, the membranes may
be ruptured. 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
atcnic contractions and relaxation and the
knees appear to give way.
Nausea Is also caused hv he nh
cal change that takes place in the brain.
There Is pressure of blood-there and the
stomach. responding. tries to empty itself.