IMPROVEMENTS IN THE MANUFACTURE OF EXPLOSIVE COMPOUNDS."
Year: 1880

page_text: LETTERS PATENT to Samuel Joseph Mackie, of Linden Grove, Peckham, in
the County of Surrey, Civil Engineer, for an Invention of "IMPROVEMENTS
IN THE MANUFACTURE OF EXPLOSIVE COMPOUNDS."
PROVISIONAL SPECIFICATION left by the said Samuel Joseph Mackie at
the Office of the Commissioners of Patents on the 18th October 1880.
SAMUEL JOSEPH MACKIE, of Linden Grove, Peckham, in the County of
Surrey, Civil Engineer. "IMPROVEMENTS IN THE MANUFACTURE OF EXPLOSIVE
COMPOUNDS."
The nitration of gun-cotton has hitherto been effected by saturating the gun-
cotton more or less with solutions of ordinary commercial or ordinary refined
nitrate of potash or nitrate of soda; but from imperfect refinement by the usual
process, and the presence of impurities in these salts, the conditions of their com-
pounds with gun cotton as heretofore made, especially those of nitrate of soda,
have been so changeful, deliquescent, and unsatisfactory, that any commercial
products have failed to result.
Now, my Invention consists in the production of a very safe and powerful
explosive-compound which can be manufactured, stored, and transported with safety
in a damp uninflammable state, and yet can be exploded without the use of a dry
primer, by means of a special detonator or fulminating cap of extraordinary power,
when required for blasting or similar purposes.
For the compounds with gun-cotton, the nitrate of soda is chemically prepared
in a perfectly dry state by the elimination of the chlorides. It is then finely ground
and intimately and uniformly incorporated in an incorporating mill with heavy
rolls, in the proportions of from 30 to 50 per cent. or more with the gun-cotton,
which is wetted or damped to the extent of from 8 to 30 per cent. of water. In
this state of damp meal, the compound is moulded into form and pressed into solid
cubes, discs, slabs, and other convenient shapes by hydraulic or mechanical power.
In this state the compound is uninflammable, but it can be exploded by a very
powerful detonating cap containing twenty grains or more of fulminating com-
position or of fulminate of mercury, according to the requirements of the particular
explosive-compound.

page_text: The gun-cotton as above incorporated is very finely pulped or crushed so as to
admit of very intimate incorporation with the nitrate of soda, whereby compounds
of regular proportions of ingredients are accomplished, such as would be unattainable
by mere saturation of the gun-cotton. The gun-cotton used is of the highest
quality, containing not more than 13 per cent. of soluble matter.
The range of proportions of admixture of chemically dry nitrate of soda with the
gun-cotton provides for the varying conditions of manufacture, the purposes to which
the explosive-compounds are to be applied, and the nature of the work to be done.
For special naval and military work, I prefer to use 66 parts of gun-cotton, and
34 parts of nitrate of soda; for general naval and military work, and ordinary
blasting, 55 parts of gun-cotton, and 45 parts of nitrate of soda; and if the quality
of the gun-cotton be inferior to the above, the nitrate of soda must be pro-
portionately varied to furnish the amount of oxygen requisite for complete
combustion.
Acceleration of explosive effects or control of them may also be made by variations
in the proportions of the ingredients.
If the nitrate of potash be substituted for the nitrate of soda, the proportions of the
ingredients in the compounds must be arranged according to known chemical data.
Other compounds of gun-cotton and other explosives in a damp state can be
exploded by special detonators of extraordinary power, similarly to the above.
In order to prevent the evaporation of moisture whilst the charges are in storage,
and to keep them in an uninflammable state, I coat the cubes, discs, slabs, and
other solid forms, with waterproof composition, and which coating serves also to
prevent solution and loss of the nitrate when the charges are used in water or in
wet places. Sometimes I employ paraffin, but preferably I use a composition of
gelatine, rendered impervious by chemical salts.
Hitherto, ordinary refined nitrate of soda has been unfit for gunpowder, rocket-
composition, and the like, but gunpowder can now be made of the chemically dry
nitrate of soda prepared as above, and rocket and other compositions.
For securing the fuze in the charge, I insert a metal tube split or open at the
exposed end, and having a nick turned over on each side, inwards, so that when
the fuze is put in, it can not be drawn back, on account of the grip the nicks have
upon it. I sometimes use for cheapness a simple metal tube or metallic coil, and I
nip the same closely on the fuze which effects the firing.
Further, for the prevention of accidents in loading holes or other spaces in which
the cartridges or charges fit tightly, I perforate the same with a central hole, or I
form the disc, cube, or other solid form, with a groove or flat land on the side,
whereby in case of ignition of the charge by friction, the gas generated in the lower
part of the borehole or space can find vent and escape. This means of safety is
applicable to any solid charge or cartridge of any explosive.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Samuel Joseph Mackie in the Great Seal Patent Office on the
18th April 1881.
SAMUEL JOSEPH MACKIE, of Linden Grove, Peckham, in the County of
Surrey, Civil Engineer. "IMPROVEMENTS IN THE MANUFACTURE OF EXPLOSIVE
COMPOUNDS."
The nitration of gun-cotton has hitherto been. effected by saturating the gun-
cotton more or less with solutions of ordinary commercial or ordinary refined
nitrate of potash or nitrate of soda, but from imperfect refinement by the usual
processes and the presence of impurities in these salts the conditions of their
compounds with gun-cotton as heretofore made, especially those with nitrate of
soda, have been so changeful, deliquescent, and unsatisfactory that any commercial
products have failed to result.
Now my Invention consists in the production of a very safe and powerful
explosive-compound, which can be manufactured, stored, and transported with safety
in a damp uninflammable state, and yet can be exploded without the use of a dry
primer by means of a special detonator or fulminating cap of extra-ordinary power
when required for blasting or other similar purposes.
In
For compounds with gun-cotton the nitrate of soda is chemically prepared in a
perfectly dry state by the elimination of the chloride It is then finely ground
and intimately and uniformly incorporated in an incorporating mill with heavy
rolls in the proportion of from 30 to 50 per cent. or more with the gun-cotton,
which is wetted or damped to the extent of from 8 to 30 per cent. of water.
this state of damp meal the compound is moulded into form and pressed into solid
cubes, discs, slabs, and other convenient shape by hydraulic or mechanical power.
In this state the compound is uninflammable, but it can be exploded by a very
powerful detonating cap containing 20 grains or more of fulminating composition
or of fulminate of mercury, according to the requirements of the particular explosive-
compound. The gun-cotton, as above incorporated, is very finely pulped or crushed
so as to admit of very intimate incorporation with the nitrate of soda, whereby
compounds of regular proportions of ingredients are accomplished, such as would
be unattainable by mere saturation of the gun-cotton. The gun-cotton used
is preferably of the highest quality, containing not more than 13 per cent. of
soluble matter.
The range of proportions of admixture of chemically dry nitrate of soda with
the gun-cotton provides for the varying conditions of manufacture, the purposes
to which the explosive-compound is to be applied, and the nature of the work to
be done. For special naval and military and highly disruptive work I prefer to
use 66 parts of gun-cotton and 34 parts of nitrate of soda; for general naval and
military work and ordinary blasting, 55 parts of gun-cotton and 45 parts of nitrate
of soda, and if the quality of the gun-cotton be inferior to the above, the nitrate of
soda must be proportionately varied to furnish the amount of oxygen necessary
for complete combustion. Acceleration of explosive effects or control of them may
also be made by variations in the proportions of the ingredients.
In order to prevent the evaporation of moisture whilst the charges are in storage
and to keep them in an uninflammable state, I coat the cubes, grains, discs, pellets,
and other solid forms with waterproof composition, and which coating serves also
to prevent solution and loss of the nitrate when the charges are used in water or
in wet places. Sometimes I employ paraffin, also collodion, compound of tar and
rosin, with or without other materials, solution of india-rubber, shellac, &c.; but I
prefer to use a solution of gelatine rendered impervious by bichromate of potash or
other chemical salts.

page_text: For securing the fuze in the charge I insert a metal tube split or open at the
exposed end, and I secure its adhesion to the charge by pressing it firm into it by
a plunger or other mechanical means. This metal tube has a nick turned inwards
on each side, so that when the fuze is put in it cannot be drawn back on account
of the grip the nicks have upon it. I sometimes use, for cheapness, a simple metal
tube or a metallic coil, and nip the same closely on the fuze which effects the firing
by suitable pliers.
The compounds of gun-cotton with chemically dry nitrate of soda can be used in a
dry condition, and the dry charges can be similarly waterproofed to prevent solution
of the nitrate. Absolute gun-cotton, and compounds of gun-cotton with nitrate of.
potash, nitrate of baryta, and chlorate of potash can be exploded in a damp state
by sufficiently powerful detonators.
What I claim is,―
1. The manufacture of an explosive-compound of a superior character by com-
pounding chemically dry nitrate of soda with finely divided, pulped, or crushed
gun-cotton by incorporation effected in an incorporating mill or by other
mechanical means, substantially as herein described.
"
2. The manufacture of my improved explosive-compound in solid forms by
moulding the materials and coating the same in their state of damp solid charges
with waterproof composition in order to prevent the evaporation of the moisture,
as also to prevent loss of the nitrate by solution when the charges are applied in
water or wet places, substantially as herein described.
3. The application of a metal tube or coil to such solid charges prepared as above
for gripping the firing fuze, substantially as described.
In witness whereof, I, the said Samuel Joseph Mackie, have hereunto set
my hand and seal, this Eighteenth day of April, in the year of our Lord
1981
S. J. MACKIE. (L.S.)