Perrysburg journal. (Perrysburg, Wood Co., O. [Ohio]) 186?-1965, 1876-03-24
How GnnpoMder Bnrns.

POPULARITY speaking the firing Of n gun
is an instantaneous process; the ignition
of the charge and the movement of the
bullet being to all appearance simultanc-
Gus. But although a large mass of gun.
powder in q eloso cavity Is ipfanied with
anaking rapidly, tlis inflammation Is
hot Instantaneous We know tllat there
are other expi0sivo substances such as
eun.eotton, nilfp-glycefine and various
Illuminating powders, which hrc much
more rapidly than gunpowder; but IL
would be wrong to say that the rapidity
of their combustion was more instantane
BUS. than that of gunpowder, because in
stantanoOusness can admit of no degrees.
Looking at the question, therefore, from
this point of view, We are forced to ac-
knowledge that there must be some dura-
I.iion of time IN the Burning Of tie charge.
| The length Of That duration may be 90
Small that we can scarcely conceive II.
scientifically speak ing, however, there is
| a very apprcoiable duratlon Of time be-
! tween the Hrst Ignition OF Charge of gun
powder and the conversion of the whole
mass into gas; moreover, this duration is
comparatively greater or less under dif-
icrent, conditions. When, on the dis
charge of a gun, the fire reaches the
charge from dc, touch hole, tho nearest
grains of powder are kindlcd the heated
gas evolved pcrmeates through the charge,
successively ignitng each grain, and the
grains then burn until consumed. Thus
| We have-first, theignition of n small por.
tion of the cl argc; next the excessively
rapid, although not instantaneous ignition
OF every grain; and, lastly, the consump.
ton of these grains. All'this process re-
quircs time, although, rs celebrated en-
| gineer put it, II may be task for our con-
ception to grasp these events, following
ono another in distinct succession, each
having its beginning, middle, and end,
and all being comprised in the period Of
| less than the one-hundrcdth part of sec
ond. But IL we can master this in iinag-
| ination it will not be difficult to under
stand how the action of gunpowdcr can
\ be controlled and how the monster guns
| have become possible. il Is apparent that
on The ignition of the charge each grain
| in its turn becomes inilamed over the
whole surface, and continues burning un-
ill II is consumed. Il Is also evident that,
as a large grain will take longer time to
burn than a small grain, all other condi.
| tions being the same, a charge composed
of large grains will take longer to burn
than the same weight OF charge made up
of smaller grains. Thus the larger the
| grain the less the rapidity of combustion.
But The size 1.-the grain also Affects the
| rapidity of ignition, rs II is easier for the
gas FIRST evolved to permeate through the
intersticcs of mass of large grains than
through those of small graius. Moreover
any cause which hinders or impedes regu-
larity of ignition, particularly in
large and long charges, is liable to
give rise to oscillations in the gas by which
| The pressure in the bore of the gun
may be locally intensified without the
velocity of the Shot being increased. We
can see, therefore, that large grains will
burn slowly and ignite rapidly, and that
in a charge composed of large grains The
combustion viii be slow and regular 1t
follows from this that the explosion of
| such charge will be attended by grad
ualll increasing and uniformly applied
| pressure until at length the maximum
strain is arrivedat. We are thus enabled to
! communicate sufficiently high velocity
10 the shot without overstraining the gun,
OF, as Sir William Armstrong puts it, by
using MISUNDERSTANDING q powder, less heat
and pressure are evolved at first, and the
4 waste of heat in, the stage of initial press
ure being less, more heat remains for ex-
pansive action. Hence the slower burn
luS pOWucI 10 NcdhCl at ulSti bul SllOilBCl
afterward, and, although the total guam
tity of gas may be only the same, and the
pressure not so great at any point, yet the
aggregate pressure throughout the bore
may equal that of the more energetic and
more dangerous powder. We have thus
been led TO increase the size of cannon
powder from small grains to large Jumps.
A bag of onion seed would very fairly rep
resent the charge of the GS.pounder of
1855, while sack of potatoes would not
be bad parallel TO suggest the size of
the charge of the Sl,ton gun of 1870
london Times.