Year: 1872

more and more slowly, until it's impulse
is graded by experiment to suit the
weight of the great projectile.


The same is true in blasting. Some
kinds of rock are exceedingly brittle,
and need very slow powder, so that the
motion may be transferred to large
masses. Other kinds of rock, and all
metals found pure in their mines, if an
attempt be made to blast them with
slow powder, will merely through out
their tamping making harmless report
like SO many gun-barrels, but the rock
or metal will not be rcnded nor thrown
down.


Indeed, in the copper mines of Lake
Superior gunpowder is found to be very
nearly useless. And by chisels and
sledgehammers the ductile masses of
metal are laboriously cut up. The
same has proved true of the metallic
iron found in Missouri at Pilot Knob
and Iron Mountain. There is need
of quicker powder for these tough
customers, while in the mining of coal
and in quartz workings slow powder
is needed.


1t is not little interesting to notice
that for this demand for quicker pow
der, the resources of nature explored
by art bid fair to furnish a supply, the
salts of silver and mercury have been
known for ages as fearful detonators;
but except for primers and PERCUSSION
caps these salts are too costly for use in
the arts. Not many years ago, ordina-
ry cotton fibre, and afterward woody
fibre of any kind, treated with the pow
erful nitric acid, were found to have ac-
qrlired many of the properties of gun
powder-which indeed they are, less
the sulphur and potash.


Gunpowder is a mechanical mixture
of carbon. saltpetre and sulphur.


Gun-cotton, in like manner isa chem
ical combination of carbon, and nitric
acid, whose oxygen in amazing volume
gave worth and energy to the saltpetre
in our ordinary gunpowder.


But, as was to have been expected,
the chemical union is so much more in
innate than any mechanical union can
be, the atoms of carbon being brought
SO much nearer to the atoms of oxygen
than any puiverizing operation can
bring them, the resulting explosion is
quick compared with gunpowder,
Thus feck of gun-cotton can be laid
upon little pile of gunpowder and ex-
ploded leaving the gunpowder safe. 1t
takes gunpowler little time to get on
fire. Before it can make up it's mind to
burn, the gun-cotton has got through
asking.


This quickness of gun-cotton units
it for use in ordinary firearms, just as
the quickness of rifle powder units it
for use in the great Rodman gun.


AS is we'll known again, all oils and
fats, and that singular substance, gly-
cerine, are hydrocarbons. Here again,
as in the case of gunpowder and gun
cotton, we have the old familiar agent
carbon. If treated with nitric-acid
we shall have the famous nitro -glycer-
inc oil whose feats in the way of explo-
sion have astonished and Mortified.


This class of explosives is rapidly en-.
larging its members The attention OF
miners and engineers is turning in this
direction, hoping to obtain an agent
for blasting that will equal gunpowde,
in power to develop force, and excel it
i'll quicllness.


There is need of servant that shall
rend masses of copper and tin andiron
rs coal and metallic ores are now rent
by gunpowder. This agent will yet be
found. But as yet, though there are
several that do the work we'll, they arc
all Objectionable on account of the dan
ger that attends their use. Here i.
where gunpowder surpasses them all
Gunpowder is safe. No man was cvel
hurt by gunpouder except by his owl
ignorance or carelessness or that OF
some other man. Speak well of ou1
servant gunpowder.