IMPROVEMENTS IN THE MANUFACTURE OF PYROXYLE OR GUN COTTON, AND FOR APPLICATION THEREOF AS AN EXPLOSIVE, AND IN THE MANUFACTURE OF SAFETY FUSE
Year: 1877

page_text: LETTERS PATENT to Simon Davey, of Rouen (France), Manufacturer, for the
Invention of "IMPROVEMENTS IN THE MANUFACTURE OF PYROXYLE OR GUN
COTTON, AND FOR APPLICATION THEREOF AS AN EXPLOSIVE, AND IN THE
MANUFACTURE OF SAFETY FUSE."
Sealed the 11th January 1878, and dated the 25th July 1877.
PROVISIONAL SPECIFICATION left by the said Simon Davey at the Office of
the Commissioners of Patents on the 25th July 1877.
SIMON DAVEY, of Rouen (France), Manufacturer. "IMPROVEMENTS IN THE MANU-
FACTURE OF PYROXYLE OR GUN COTTON, AND FOR APPLICATION THEREOF AS AN
EXPLOSIVE, AND IN THE MANUFACTURE OF SAFETY FUSE."
This Invention relates,-
Firstly. To oxidizing gun cotton by a supplementary bath or solution of suitable
salts, more especially by a solution of chromates, sesqui-chromates, or bichromates,
with or without the addition of gum or hydrocarbon, or of alkaline carbonate, or of
separate bath to fix the chromate.
Secondly. The application of such oxidized gun cotton to the purposes of explosives
in general, and to the manufacture of safety fuse for blasting purposes.
Ordinary gun cotton consists of cellulose fibres of textile matter, whether cotton,
flax, hemp, jute, or other or of similar material, first pulped into paper and after-
wards treated in the usual manner with nitric acid, or with nitro-sulphuric acid, or
with sulphuric acid, in which a sufficient quantity of nitre has previously been
mixed or dissolved. It is then repeatedly washed to get rid of all traces of free
acid, and is either kept in a wet state or dried for use. But such ordinary gun
cotton does not contain a sufficient quantity of oxygen to secure the thorough com-
bustion of all its elements, that is to say, to secure the full theoretical developement
of its power.

page_text: My Invention consists in adding to the gun cotton so made and washed a further
complement of oxygen to the required extent to give the full theoretical strength,
and this I obtain by passing the gun cotton through a bath or solution of chromate
or bichromate of potash, or other chromate with alkaline base, such as chromate of
soda, of ammonia, or chromate of barytes; or to the solution of chromate, sesqui-
chromate, or bichromate may be added a certain proportion of solution of nitrate or
other soluble salt containing oxygen in abundance; or a certain proportion of gum
or of hydrocarbon, or of carbonate of potash, to counteract any tendency to acid
reaction in the gun cotton.
The chromates may be fixed in the gun cotton by the use of a separate bath or
solution of acetate or other suitable salt, which separate bath may be used either
before or after the chromate solution.
I reserve to myself the right to compress such chromated or oxidized gun cotton
in suitable moulds, so as to form discs, prisms, cubes, or cylinders of such dimensions
and shape as may be most suitable for the changes or work to be done, whether for
war purposes or for mining works.
I also reserve to myself the right to apply such chromated or oxidized gun
cotton to the manufacture of safety fuse instead of the ordinary powder hitherto
generally used.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Simon Davey in the Great Seal Patent Office on the 24th January
1878.
SIMON DAVEY, of Rouen (France), Manufacturer. "IMPROVEMENTS IN THE MANU-
FACTURE OF PYROXYLE OR GUN COTTON, AND FOR APPLICATION THEREOF AS AN
EXPLOSIVE, AND IN THE MANUFACTURE OF SAFETY FUSE."
My Invention consists of an improved production of pyroxyline or gun cotton,
and in the application thereof to the manufacture of fuse for blasting or other
purposes.
The pyroxyline or gun cotton is first prepared in the ordinary manner from
cotton or other suitable cellulose matter, and is afterwards chromated or passed through
a bath or baths containing solutions of chromates or other oxidizing compounds.
The pyroxyline or gun cotton prepared in the ordinary manner, and when used
alone or with the addition of nitrate of potash only for the manufacture of safety
fuse, will not convey fire when under pressure and in a small column or line, as is
the case in a mining fuse when in a tamped hole for blasting; and if chlorate of
potash be added to pyroxyline, a dangerous article is thereby made, which is liable
to take fire from comparatively slight friction, even in my own experience, by
merely cutting it with a penknife, so that the chlorated pyroxyline is not suitable
for mining purposes, nor is it safe to use it or to store it where explosives are used
or stored.
I produce an improved pyroxyline, which is safe in use and suitable for the
manufacture of mining fuse, in the following manner :-I first thoroughly wash the
pyroxyline, so as to deprive it of all free acid, and then saturate it with an oxidizing

page_text: solution by passing it through a bath or baths of solution of chromate of potash or
of bichromate of potash, or of nitrate of sesqui-oxide of chrome, or of other soluble-
chromate, such as chromate of ammonia; and to any of these solutions I can in
certain cases add a solution of nitrate of potash or other soluble salt capable of
supplying oxygen in abundance, with or without the addition of gum or of hydro-
carbon.
The proportion of the various acids absorbed in the first instance by the cellulose
from which the pyroxyline is formed will vary according to the nature of the
cellulose matter, and to the strength of the acids employed, and also to the length
of time the cellulose body is allowed to remain in the acid bath; and the proportion
of chromate or other oxydizing body absorbed will in like manner depend on
the strength of the solution employed, and on the length of time during which the
pyroxyline is allowed to remain in the oxidizing solution.
Weaker pyroxyline than that commonly used for explosive purposes can, when
well chromated, be made to burn under pressure, and can thus serve for the purpose
of making ordinary fuse; but for special qualities of fuse the stronger pyroxyline
thoroughly chromated may be employed.
In ordinary cases one hundred parts by weight of cotton yarn would give a
sufficient strength in about one hundred and fifty parts by weight of pyroxyline,
and in from one hundred and seventy-five parts to two hundred parts by weight of
chromated or super-oxygenated pyroxyline.
I can fix the chromate, or a considerable portion thereof, in the pyroxyline by
passing it through a bath or solution of acetate of lead, or other suitable salt, either
before or after the chromate bath.
I can apply this chromated or super-oxygenated pyroxyline, prepared as above,
in the state of threads, yarns, bands, or cords, or otherwise in the manufacture of
safety fuse as a substitute for the ordinary powder centre of such fuse; and in such
safety fuse I can render the pyroxyline centre waterproof, independently of the
body of the fuse itself, which may or may not be also rendered externally water-
proof by any of the ordinary means.
I can place a waterproof coating or covering upon or around the super-oxygenated
or chromated pyroxyline centre, whether of gutta percha, india-rubber, or collodion,
or surround it with an envelope made waterproof by the application of paraffine,
beeswax, pitch, or other impervious material, spinning if necessary the usual spiral
threads around and outside of such waterproof coating instead of placing, as hereto-
fore, the waterproof coating outside the spiral threads which form the cord or body
of safety fuse.
The waterproof coating applied by my new system will have the advantage of
being protected by the spiral threads placed outside of it from any injury during
carriage from one spot to another, or during the process of tamping or otherwise;
or I can make the fuse to consist merely of a super-oxygenated or chromated
pyroxyline centre (without any chloride of potash) coated, as described, with
a waterproof coating, suppressing altogether the external spiral threads. Or I
can use chromated pyroxyline in the shape of pulp or paste, or in a granulated form,
within a lead tube or other ductile metallic tube, and draw it out to the length
required, so as to form a metallic waterproof safety fuse.
Having thus described the nature of my Invention, and the special application
thereof, I wish it to be understood that I do not claim generally the improving of
the manufacture of pyroxyline by the addition of an oxidizing compound, as I am
aware that such improvement has already been proposed; and I further disclaim
the application as such oxidizing compound, either of nitrate of potash alone, or of
chlorate of potash, for the manufacture of safety fuse; but what I claim is,-
Firstly. Combining gun cotton or pyroxyline to be used for the manufacture of
fuse with soluble chromates or bichromates, or other suitable oxidizing bodies other
than chlorate of potash, and with or without the addition of nitrate of potash.
Secondly. The mode of rendering such chromated or super-oxygenated gun cotton

page_text: or pyroxyline waterproof in the centre of the fuse, such fuse being itself made
again waterproof by an external coating or not.
Thirdly. The manufacture of metallic waterproof safety fuse with a centre of
chromated or super-oxygenated pyroxyline.
In witness whereof, I, the said Simon Davey, have hereunto set my hand
and seal, this Fifteenth day of December, One thousand eight hundred
and seventy-seven,
Witness,
CH. ARMENGAUD,
Civil Engineer,
No. 23, Bd. des Strasbourg,
à Paris.
SIMON DAVEY. (L.S.)