Improvements in or relating to Percussion Caps or Fuzes.
Year: 1888

page_text: Date of Application, 22nd Nov., 1888.
Complete Specification Left, 15th Aug., 1889-Accepted, 28th Sept., 1889---
PROVISIONAL SPECIFICATION..
Improvements in or relating to Percussion Caps or Fuzes.
I, HERBERT MANNING CHAPMAN of Sydney Villa, Sydney Road, Waltham Cross
in the County of Essex, Analytical Chemist, do hereby declare the nature of this
invention to be as follows:-
The principal object of the present invention is to effect the ignition of those nitro
explosives generally known as "high" explosives in firearms ordnance and the like
without producing "detonation" which as is well known has frequently resulted in
the bursting of guns. These same caps or fuzes can however be also used with
ordinary black powder if desired.
The detonation appears only to be produced when the nitro explosive is fired by
means of fulminate of mercury alone or mixed with chlorate of potash, and I there-
fore effect iny object by dispensing with these preparations altogether and employing
in their place some material giving a longer flash and greater igniting power. It
will be understood that a very large number of different materials will suit my purpose
but without naming all or nearly all of these it will be sufficient to indicate a few of
them as follows:-
I prefer to combine metallic pulverized zinc Magnesium Antimony or Aluminium
or powdered glass with a suitable composition of the Perchlorates chlorates Picrates
or Nitrates of Barium Copper Lead Potassium Sodium Mercury or Ammonium.
COMPLETE SPECIFICATION.
Improvements in or relating to Percussion Caps or Fuzes.
I, HERBERT MANNING CHAPMAN, of Sydney Villa, Sydney Road, Waltham Cross,
in the County of Essex, Analytical Chemist, do hereby declare the nature of this
invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
The principal object of the present invention is to effect the ignition of those nitro-
explosives generally known as "high" explosives in fire-arms, ordnance and the
like without producing "detonation" which as is well known has frequently resulted
in the bursting of guns. These same caps or fuzes can however be also used with
ordinary black powder if desired.
The detonation appears only to be produced when the nitro-explosive is fired by
means of fulminate of mercury alone or mixed with chlorate of potash, and I there-
fore effect my object by dispensing with the fulminate of mercury altogether and
employing in its place some material giving a longer flash and greater igniting
power. It will be understood that a very large number of different materials will
suit my purpose but without naming all or nearly all of these it will be sufficient to
indicate a few of them as follows:-
I prefer to combine metallic pulverized zinc, magnesium, antimony, or aluminium,
and powdered glass, with a suitable composition of the perchlorates, chlorates,
picrates or nitrates of Barium, Copper, Lead, Potassium, Sodium, Mercury, or

page_text: rnosphorus.
To this list might be added a long list of Hypophosphites Sulphides Oxides Per-
oxides Sulphur and the like.
or
The explosives variously known as " nitro-explosives" "high explosives
shattering explosives" in contradistinction to such explosives or classes of explosives
as gunpowder (which is a mechanical mixture of nitre, sulphur and charcoal) are all
capable of undergoing what may be termed sympathetic explosion or " detonation
if a detonating fuze containing fulminate of mercury in sufficient quantity is
exploded in contact with them.
"
The specific action of detonating bodies like fulminate of mercury upon nitro-
explosives appears to be due to the influence of vibratory motion or sound
sufficiently acute to determine the practically instantaneous decomposition of the
whole mass into gaseous products, it being generally understood that the vibration
imparted to the surrounding medium by detonation is transmitted with the velocity
of sound and that the explosion becomes rapid in proportion, thus accounting for the
extremely destructive effects of nitro-explosives when exploded in this manner.
When heat alone is the cause of the explosion it must be comparatively slow.
That detonation is not produced by heat alone is proved by the well known fact
that a mass of wet gun cotton may be detonated if the initial detonation is set up by
a fulminating fuze imbedded in a primer of dry gun cotton in contact with or in
close proximity to the mass of wet gun cotton.
The pressure developed by the detonation of compressed gun cotton has been
estimated by Berthelot at about 160 tons per square inch, and the same observer
finds that even such stable gases as acetylene, nitric oxide and cyanogen are
decomposed into their elements by the detonation of fulminate of mercury.
In ordinary fire-arms or ordnance in which nitro-explosives are used as the
propelling agents it sometimes happens that an abnormally violent explosion is set
up known as "detonation" resulting in the destruction of the fire-arm and loss of
life or limb to the person using it.
This so-called detonation or instantaneous explosion is believed to be caused by the
sharp initial shock or concussion imparted to the nitro-explosive by the ordinary
percussion cap containing fulminate of mercury or other fulminate usually mixed
with oxidizing agents such as Chlorate or Nitrate of Potash and sometimes with
Sulphide of Antimony or like substances in addition.
This property of imparting a detonative effect to nitro-explosives possessed by the
fulminates renders the use of percussion caps containing them dangerous and
uncertain always in fire-arms or ordnance when nitro-explosives are used as the
propelling agents, and I therefore employ percussion caps that contain no fulminate
but a suitable composition of chemical bodies that will ignite the nitro-explosive or
other propelling agent equally well without the risk of detonation.
To accomplish this I prefer to use such of the substances mentioned in this
specification as may be necessary for any particular composition though I do not
always adhere to the exact proportions and methods of mixing laid down as these may
be varied without impairing the utility of the invention.
Commercial Amorphous Phosphorus sometimes shows an acid re-action and before
using it in these compositions it requires special treatment.
To effect this the Amorphous Phosphorus is put into boiling distilled water and
sufficient pure carbonate of potash or soda added to neutralize the acid present and
to make the liquid alkaline.
The liquid is then filtered from the phosphorus, and the Phosphorus washed on the
filter repeatedly with hot water to remove excess of alkali and other soluble
impurities.
The greater part of the water can be removed by pressure from the Amorphous
Phosphorus and from 2 to 5% of Oxide of Magnesia, or of Carbonate of Lime added
and mixed, or from- 2 to 5% of Carbonate of Potash or Soda: the required pro-
portion of the two latter salts may be dissolved in a little water; the solution added
to and mixed with the Phosphorus and the whole dried.

page_text: Again in No. 1 the cane sugar may be replaced by an equal weight of lamp black
or of charcoal and the magnesium by powdered Aluminium, Antimony, or Zinc, but
whatever alterations are made they must not impair the sensitiveness to percussion
requisite in the percussion cap.
These compositions may be adjusted to almost any required degree of sensitiveness
by varying the proportions of Amorphous Phosphorus and Chlorate of Potash but
there is no practical advantage to be gained by making them unduly sensitive.
A method of mixing either of the compositions set forth (No. 1 for example)
which I have found satisfactory is to weigh out the Amorphous Phosphorus, Resin,
Cane Sugar, Mercuric Oxide, Peroxide of Manganese, Magnesium and the Nitre first
to heap these up on a flat wooden board or sheet of thick india-rubber, then damp
the ingredients with a little water, adding the chlorate of potash last and after the
damping of the other ingredients, and incorporating the whole with a wooden or
vulcanite spatula until the ingredients are thoroughly mixed. The slightly damp
mass should then be flattened out in suitable trays such for example as cardboard,
wooden or paper trays and either allowed to dry or should be dried by the aid of a
gentle heat.
Too much water must not be added or the drying will take an unnecessarily long
time.
The dry composition if cakey may be reduced to powder by gently rubbing small
portions at a time between two india-rubber sheets about of an inch thick but
whatever method is adopted of mixing and preparing the composition by hand, I
prefer not to mix more than four ounces at one time.

page_text: The above method of mixing which may be termed the wet method takes longer
and is more troublesome than dry methods when carefully done, but in mixing by
dry methods care must be taken that all the ingredients are thoroughly dry and
finely powdered or they will not thoroughly mix and all possible chance of percussion
or friction scrupulously avoided.
In mixing dry compositions of this kind 1 prefer to do so in a copper drum or
cylinder of small diameter set at an angle and turning on an axis the cylinder being
rotated at a regular speed by suitable means such as machinery or clockwork in an
isolated place when large quantities are prepared or in a chamber the walls of which
may be earth to deaden the force of explosion should such occur or in pits sunk in the
earth.
The caps may be filled with the improved composition in the well known manner.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed i declare that what I
claim is :-
1. A percussion cap for the ignition of nitro- or similar explosives in fire-arms
and ordnance containing a composition without any fulminate.
2. For the ignition of nitro- or similar explosives the employment of a composition
without any fulminate.
.
3. A composition for percussion caps for use with nitro or similar explosives con-
sisting substantially of the ingredients and in the proportions specified under the
heading No. 1 in this specification.
4. A composition for percussion caps for use with nitro- or similar explosives
consisting substantially of the ingredients and in the proportions specified under the
heading No. 2 in this specification.
5. A composition for percussion caps for use with nitro- or similar explosives con-
sisting substantially of the ingredients herein specified.
Dated this 14th day of August 1889
HERBERT MANNING CHAPMAN.
W. P. Thompson & Boult,
Agents for the Applicant.