IMPROVEMENTS IN THE MANUFACTURE OF EXPLOSIVE COMPOUNDS
Year: 1879

page_text: LETTERS PATENT to Henry Edward Newton, of the Office for Patents, 66;
Chancery Lane, in the County of Middlesex, Civil Engineer, for the Invention
A
of "IMPROVEMENTS IN THE MANUFACTURE OF EXPLOSIVE COMPOUNDS."
communication from abroad by Alfred Nobel, of Paris, in the Republic of
France.
Sealed the 2nd December 1879, and dated the 17th June 1879.
PROVISIONAL SPECIFICATION left by the said Henry Edward Newton at
the Office of the Commissioners of Patents on the 17th June 1879.
HENRY EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane, in the
County of Middlesex, Civil Engineer. "IMPROVEMENTS IN THE MANUFACTURE
OF EXPLOSIVE COMPOUNDS." [A communication from abroad by Alfred Nobel, of
Paris, in the Republic of France.]
There are three classes of compressed gunpowder known, viz., 1, that which is
compressed while in a moist condition; 2, that which is compressed when heated up
to about 212° Fahrenheit, at which temperature the sulphur contained therein
becomes soft and yielding; and 3, that which is compressed at a still higher, tein-
perature when the sulphur melts and fills up the pores in the powder. Those
powders are all of slower combustion than grained gunpowder, the last above
named being by far the slowest of all.
In order to utilize compressed gunpowder of the first kind here named (com-
pressed when moist) for artillery purposes, various expedients have been resorted to,
such as perforating it in order to increase the surface of combustion, and thereby
quicken its too slow explosive action.
In order to make it useful for blasting purposes, for which it is also too slow, it
has been compressed in a granular instead of mealed condition, but although its
specific gravity is thereby increased, the advantage of a denser explosive so

page_text: important to the miner is only apparent in as much as the rigid form of the com-
pressed powder cylinder wastes in wirdage what is gained in density.
As regards the third kind of compressed powder herein named (compressed when
the sulphur is melted), it is so slow that it has been found necessary to break it
up into small fragments in order to be able to utilize it for guns.
Having thus described how compressed gunpowder has been utilized hitherto,
I now proceed to describe the nature of improvements therein, which constitute the
subject of the present Invention.
Instead of perforating compressed gunpowder of prismatic or other form when it
is to be used for guns, its combustion is quickened by adding to the charge a
quantity of ordinary grained quick gunpowder, or other suitable explosive sub-
stance of quick action. The relative quantity of the two kinds of powder to be
used will depend on the quickness of combustion of each, and in a great measure
also on the caliber of the gun for which it is to be used, and the weight of the
charge which it has to sustain, it being understood that the heaviest gun is most
likely to burst, and requires therefore the lowest pressure and consequently the
greatest relative quantity of compressed and the least of grained powder.
compressed gunpowder prefered for use in cannon is the third kind above named
(compressed while the sulphur is melted) on account of its non-porosity, which
causes it to burn only from the surface. It is preferred to use it in cylinders or
cubes of such size as may be needed, and the charge is formed as already stated by
adding more or less of grained (quick) gunpowder, which activates the combustion
of the compressed powder without overstraining the gun. By judiciously varying
the relative portions between the two kinds of powder, the pressure which the
gun is intended to sustain will never be exceeded.
The
In order to utilize compressed gunpowder for blasting purposes, it is formed when
mealed into cylinders of sizes suitable for the niner's use, with a small hole right
through in its centre. Into the hole when the compressed cylinder is to be fitted
for immediate use an exploder as well as a Bickford fuse is inserted. The exploder
consists of a small tube or cap containing a strong charge of some violent explosive
substance, such as mercury, fulminate, picrate of potash, picrate of lead, or
analogous substances, or mixtures of such with chlorates or nitrates. The tube
or cop to contain the fulminate may be made of lead, copper, paper, or any other
suitable material. A very easy and practical way of preparing such exploders is to
draw out leaden tubes filled with fulminate to the diameter intended, and then cut
such tubes up into suitable lengths, taking care to fix with a little collodion
solution the exposed fulminate at each end. The exploder as herein described
serves a very different purpose from that assigned to the detonators used for
dynamite guncotton. The former indeed causes no detonation to take place, and is
only intended to break up the cylinder of compressed gunpowder wherein it is
lodged into numerous fragments, thereby vastly increasing the surface of explosive
combustion, and producing besides a dense and highly heated atmosphere in the
Lore hole, which also quickens the explosion.
Such is the quickening influence of the aforesaid exploder, that the most densely
compressed gunpowder will exercise its full power even in fissured rock
When the compressed cylinders above described are intended for blasting hard
and solid rock, they may be compressed at a temperature at which the sulphur
therein contained melts. They are thus very dense and imporous, and resist for
a considerable time the action of water. But as powder compressed while its
sulphur is in a melted state is of slow combustion, it is prefered to employ in
loose or fissured ground powder, compressed while moist at the ordinary tem-
perature, and then exposed for a short time to a heated atmosphere not exceeding
300° Fahrenheit, when the sulphur contained in the powder melts at least at the
surface, and in some measure makes it resist dampness and water.
To prepare the compressed blasting cylinders herein described for use in wet
ground, they are steeped in a bath of stearine, paraffine, wax, or mixture of such

page_text: matters with rosin, so as to produce a watertight coating which can in no way
prevent or retard the explosion since the exploder herein above described, when it
is set off breaks off the charge, thus giving the fire free access to the compressed
powder. The paraffine or stearine inay of course be replaced by some varnish of the
usual kind, but these as a rule are less efficacious,
The nitrate of potassium generally used for gun and blasting powder may
advantageously be replaced by nitrate of barium, or nitrate of sodium.
Since the latter salt is somewhat hygroscopic, the water tight coating or varnish
herein before described will be found a useful protection, failing which the
cylinders of compressed powder should be wrapped in oiled, paraffined, waxed,
asphalted, or india rubbered paper.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Henry Edward Newton in the Great Seal Patent Office on the 17th
December 1879.
HENRY EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane, in the
County of Middlesex, Civil Engineer. "IMPROVEMENTS IN THE MANUFACTURE
OF EXPLOSIVE COMPOUNDS." A communication from abroad by Alfred Nobel, of
Paris, in the Republic of France.
This Invention relates to a method of imparting to highly compressed mealed, in
contradistinction to grained gunpowder, that quickness of explosion which it needs
to become useful as a blasting agent, and which also facilitates its adaptation as a
propelling agent for use in heavy gans Although grained gunpowder when com-
pressed so as to form compact cylinders readily explodes, yet a cartridge or cylinder
of highly compressed mealed gunpowder, when fired in the usual way in a miner's
borehole, only fuses like a rocket without doing any useful work. If exploded
however, it will on account of its great density and highly concentrated power
resulting therefrom, prove a very superior blasting agent.
It is found that cartridges or cylinders of highly compressed mealed gunpowder
can be exploded when charged in miners' boreholes by means of a special exploder,
which in its simplest form consists of a small primer cartridge of some very quick
explosive substance, such as the picrates of potash, baryta, or lead, with or without
the addition of the quantities of nitrate or chloride of potash needed to complete
the combustion of such picrates or dynamite, or other preparation of nitroglycerine
or gun cotton, or analogous compounds. When the exploder used with a charge
of mealed powder compressed into cylinders and under confinement, the combustion
of the powder becomes so much quickened by the hot and dense gas developed by
the exploder, as to set fire to it completely and instantaneously. The quantity of
quick explosive or fulminate needed depends on its quickness and power, and also in
a great measure on the soundness of the rock which has to be blasted; if the latter
is seamy and leaky, the charge of the exploder must be proportionately increased.
An exploder which is found to be very advantageous in practice consists of a sinall
cartridge of dynamite or blasting gelatine weighing ten grammes, and connected
with its detonator and fuse, it carries off the underlying charge of compressed
mealed powder, whatever be the nature of the rock wherein it is lodged. It has
also been found that in very hard and tight ground, three grainmes of dynamite or
analogous compound are amply sufficient to ensure the saine result. But for
practical use the charge should be at least five grammes, in order to secure a
complete explosion in nearly every ground wherein ordinary blasting powder
readily explodes.
The following ingredients will be found to make a very practical exploder, in as
much as it is insensible to percussion and concussion, and therefore readily admits
of hard tamping in mines without danger, viz., forty parts by weight of bibasic
picrate of baryta or tribasic picrate of lead is moistened with three parts by weight
of water, and roughly mixed with sixty parts by weight of quick finely grained
gunpowder. The mass thus obtained is compressed into small cakes or cylinders,
and then dried in a water bath, or otherwise. About six grammes of such a com-
pound wrapped in a paper and connected with a fuse, constitutes an exploder for
setting off compressed mealed gunpowder. The same exploder with the charge
reduced to only three grammes is an excellent substitute for the fulminate
detonators now employed for setting off gun cotton, as well as nitroglycerine
compounds when confined. The grained gunpowder mixed with pieric fulminate
is only added for the purpose of reducing the cost of the exploder.
From the above description it will be understood that the exploder consists of a

page_text: Newton & proven
small primer cartridge, the form and composition of which may be greatly varied
without departing from the purpose of this Invention, which is to quicken the
combustion of an adjoining sluggish charge of slow explosive.
I am aware that the detonators now used for setting off dynamite and gun
cotton have been tried also for quickening the combustion of gunpowder in-mines;
but such a detonator is not sufficiently strong to act as au exploder for gun powder.
No claim is made to such use of such detonators, or to any use other than with
compressed mealed gunpowder, which will not fire without the aid of a special
exploder in the manner and for the purpose hereinafter set forth.
In adapting mealed powder for use in mines it is compressed in a moist condition
as usual, and is formed into cylinders of such lengths and diameter as best fits the
niner's use. The processes employed for compressing and moulding gunpowder are
too well known to need special description. If the cylinders are formed with a
small central hole as are the cylinders of compressed grained powder now in use,
then the exploder should be so shaped that it can be lodged in the hollow formed
by the central hole, the quantity of quick explosive needed for the exploder can in
that case be reduced to three grammes, and even less, for the explosion which takes
place in the centre of the cartridge shivers it into small fragments, and thereby
quickens its combustion.
Instead of forming the compressed mealed gunpowder into cylinders, it may be
used in the shape of very large grains, which on being pushed home in the miner's
borehole are crushed therein, so as to fill up the powder room completely; the
exploder is then lodged on the top of the charge, and the hole is tamped and fired
in the usual way.
In the compressed mealed gunpowder herein described, nitrate of soda or nitrate
of baryta may be substituted in chemical equivalents for salt petre. But if the
powder contains nitrate of soda, which is hygroscopic, a packing should be provided
which excludes moisture.
The charging of a miner's borehole is effected as follows:-As many cylinders of
compressed gunpowder as may be needed to complete the charge are inserted into
the borehole; an exploder as herein described connected with a fuse, or fuse and
detonator, for explosives requiring the latter is then put in, so as to be in contact
with the charge. The hole on being well tamped or stemined is then ready, and
the fuse may be fired.
When compressed powder as above described is to be used for propelling
projectiles, such powder should be compressed, either as usual in a moist condition,
or else under one of the other two conditions practised, viz., dry, and heated up to
one hundred degrees centigrade, when the sulphur in the powder becomes soft and
yielding, or heated to a still higher temperature, when the sulphur in the powder
melts and completely fills up the pores, converting the powder when cooled into a
very solid nonporous mass. In either ease, but chiefly in the last mentioned, the
compressed powder burns too slowly for cannon, even of large calibre, and various
devices have been adapted for the purpose of increasing the surface of combustion.
This result is effected by making the compressed grains of a uniform bulk, say one
cubic inch each, and adding in the gun a small charge of quick powder or other
The relative
quick explosive, which quickens the combustion of the former.
quantity of quick and slow powder will vary with the calibre of each gun, and
cannot conveniently be fixed without numerous experiments with heavy ordnance;
but one part by weight of quick powder will greatly quicken the combustion of ten
parts by weight of slow powder.
Having thus described the nature of this Invention of "Improvements in the
Manufacture of Explosive Compounds" as communicated to me from abroad by my
foreign correspondent, and explained the manner of carrying the same into effect,
I wish it to be understood that under the above in part recited Letters Patent
5 I claim,-
Winst The manufacture
or use of charges for explosive purposes
made of

page_text: compressed mealed gunpowder, in conjunction with special primers or exploders
which quicken its combustion, substantially in the manner herein set forth.
Secondly. The use of exploders consisting of a small charge of bibasic picrate of
baryta, or tribasic picrate of lead, or analogous fulminate equally insensible to
percussion or concussion, wrapped in a paper or other soft envelope, substantially
as herein set forth and for the purposes herein described.
In witness whereof, I, the said Henry Edward Newton, have hereunto set my
hand and seal, the Seventeenth day of December, in the year of our Lord
One thousand eight hundred and seventy nine.