The Washington herald. [volume] (Washington, D.C.) 1906-1939, 1915-08-08
VELOCITY IS 4
Miles A Second
Decorating Wave for Ex-
plosives in War Shells
Has Great Speed.
ELIMINATES ARE LIMIT
Some Produce Pressure of $4,000
Atmosphere. Says Maj. Edward P.
OHern. Army Expert.

While several million pounds Of pow
der are being burned weekly on the bat
tiefields of Europe. and discussion is rife
on the American manufacture of the
products. an article on explosives. just
issued by the Smithsonian institution.
gives much timely information on the
subject.
! The paper Is written by Mai. Edward P
O'Hern. of the Ordnance Department, L.
S. A. and deals with the Importance of
so-called explosives and the increas sing
| extent of their use and production as
! we'll as their composition, uses. method
of employment and the results accom-
plished
| An explosive" SAYS Mai. O'Herr. rs
a substance of which the molecules are
made up OF number Of atoms or units
rather loosely bound together in an I'M
| stable condition, ready to seek new and
simpler combinations upon the furnishing
Of sufficient motive force TO start oper-
alton. This usually is supplied through
a primer iSnited by a slow burning fuse,
or b. wire heated BY an electric cur
rent. When started. the heat and shock
developed Will cause a continuation of
the action throughout the mass of the
! explosive. The enormous power that can
thus be developed from a comparatively
I small quantity of material is indicated
by the thousands Of fragments into which
Finch aTmor-piercIng projectile was
broken by the detonstion of a bursting
| charge about IL per cent Of its weight
Three Glasses of Explosives.
The author divides explosives into
three classes: Progressive or propeuing
explosives, known as low explosives. de-
! tonating explosives. or high explosives.
and decorators or Eliminates For all
classes the effect OF the explosion is dc
pendent upon the quantity of gas and
| heat developed per unit of weight and
volume of the explosive. the rap:di.y Of
the reaction. and the character of the
confinement. if any. given the explosive
| charge. The rapidity of reaction varies
greatly with different explosive sub
stances and with the manner IN which
| the explosive is started.
| Black eunpovder. smokeess powder
and black blasting powders are known as
low explosives for certain of which. such
as smokeiess powder. the explosion does
not differ in principle from the burning
OF a piece of wood or other coanbustlSle.
! The combustion is very rapid but Is a
| surface action proceeding from laver L
| layer until the grain is consumed. Such
| materials are known as low or progress
| i've explosives. although the total power
developed through the combusrion OF a
unit of weight may be very great and
would be destructive unless properly con-
trolled
In high explosives such as dynamite,
nitroslycerin, guncotton. some blasting
powders. and most of the permissible
explosives" approved by the United
States Bureau OF Mines for use in mines
/ where gas explosions are liable to occur.
the progress Of the explosive reaction is
11r hNr t,,.,
the breaking up of the initial molecules
! gives rise to an explosive wave which is
i transmitted with great velocity in all d.
: rections throughout the mass and causes
| its almost instantaneous conversion into
gas. The velocity of propagation of the
I decorating wave has been determined
for some materials TO he more than 20
! ~" feet per second. or approximately four
miles per second: this form of material
is used in shells and for bursting pur-
/ poses. The progressive emission of a gas
/ from a low explosive such as burning
! gunpowder. produces a pushing effect
! upon proiectile. whereas the sudden
| conversion of an equal weight o. material
into gas. as would happen with a high
/ explosive such as dynamite or nitroglvc-
erin. would develop such high pressure
and shattcring effect as to rupture the
gun.
Fulminates Most Powerful.
The action Of Eliminates is much more
! brusque and powerful than that Of the
! high explosives. Since they can be de-
| tonated by shock or the application OF
! heat. they are used in primers and fuses
! to start action in both low and high
| plosives. One of the most important full
inmates is illuminate OF mercury. which
/ produces a pressure Of about $500 at
mospheres.
, Al no time in the history Of the world
| have explosives played such a mighty
part in deciding the destiny of nations
as they playing today in the prose
cution Of the general European war.
| Their extensive use in the mighty en-
! gines of destruction such as the subma-
! rine mine. the torpedo. and in projectiles
F; thrown from cannon to great distances
with marvellous accuracy. is resulting IN
loss of life and destruction of property
| on an unprecedented scale.
! Beginning with black powder. the ear
lest record of which in actual war was
in the fourteenth century. the author fol-
lows the development of powder through
! its early stages of brown powder. TO the
! two principal forms Of smokeless pow
der for military purposes. nitrocellulose
! and nitroglycerin, stating that the use is
! quite evenly divided: the United States
! army and navy. the French army and
/ navy and the German army using the
| former. and the British army and navy
I and the German navy using the latter.
! He then gives much detailed informa-
| ton concerning the manufacture. life.
! source Of supply. and tests Of smokeless
| powder manufactured from nitrocellu-
lose or guncotton. Following which. sub
jects relating to life OF guns bursting
| charges for projectiles. armor-piercing
! proJectiles. high explosive shells. shrap-
mel. fuses. aeroplane bombs. means of
! igniting explosives. mines. torpedoes. and
! the storage and shipment of explosives
| In the limited States are discussed