Nitro Explosives: A Practical Treatise by P. Gerald Sanford

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Minor modifications have from time to time also been made, in order to
meet the gradual alteration which has taken place during this long period
in the manufacture of sporting guns and cartridge cases to be used with
this powder, but through all its evolution this Company has adhered to the
first idea of using woody fibre in preference to cotton as the basis of
their smokeless powder, as experience has confirmed the original opinion
that a powder can be thus made less sensitive to occasional differences in
loading, and more satisfactory all round than when made from the cotton
base. The powder has always been regulated so that bulk for bulk it
occupies the same measure as the best black powder, and as regards its
weight, just one half of that of black.

The process of manufacture of this powder is briefly as follows:--

Wood of clean growth is treated by the well-known sulphite process for
producing pure woody fibre, which is very carefully purified, and this,
after drying, is steeped in a mixture of nitric and sulphuric acids, to
render it a nitro-compound and the explosive base of the powder. This
nitro compound is carefully purified until it stands the very high purity
requirements of the Home Office, and is then ground with oxygen-bearing
salts, &c., and the whole is formed into little irregular-shaped grains of
the desired size, which grains are dried and hardened by steeping in a
suitable solvent for the nitro compound, and after finally drying,
sifting, &c., the powder is stored in magazines for several months before
it is issued. When issued, a very large blend is made of many tons weight,
which ensures absolute uniformity in the material.

There is in England a standard load adopted by every one for testing a
sporting powder; this charge is 42 grains of powder and 1-1/8 oz. No. 6
shot--this shot fired from a 12-bore gun, patterns being taken at 40
yards, the velocity at any required distance.

The standard muzzle velocity of Schultze gunpowder is 1,220 feet per
second.

The mean 40 yards ditto is 875 feet per second.

The mean 20 yards ditto is 1,050 feet per second.

The internal pressure not to exceed 3.5 tons.

This Company also manufactures a new form of powder, known as Imperial
Schultze. It is a powder somewhat lighter in gravity; 33 grains occupies
the bulk charge, as compared with the 42 grains of the old. It follows in
its composition much the lines of the older powder, but it is quite free
from smoke, and leaves no residue whatever.

~The E.G. Powder.~--This is one of the oldest of the nitro powders. It was
invented by Reid and Johnson in 1882. It is now manufactured by the E.G.
Powder Company Limited, at their factory near Dartford, Kent, and in
America by the Anglo-American E.G. Powder Company, at New Jersey. The
basis of this powder is a fine form of cellulose, derived from cotton,
carefully purified, and freed from all foreign substances, and carefully
nitrated. Its manufacture is somewhat as follows:--Pure nitro-cotton, in
the form of a fine powder, is rotated in a drum, sprinkled with water, and
the drum rotated until the nitro-cotton has taken the form of grains. The
grains are then dried and moistened with ether-alcohol, whereby the
moisture is gelatinised, and afterwards coloured with aurine, which gives
them an orange colour. They are then dried and put through a sieve, in
order to separate the grains which may have stuck together during the
gelatinising process.

Since its introduction soon after 1881, E.G. powder has undergone
considerable modifications, and is now a distinctly different product from
a practical point of view. It is now and has been since 1897 what is known
as a 33-grain powder, that is to say, the old standard charge of 3 drams
by measure for a 12-bore gun weighs 33 grains, as compared with 42 grains
for the original E.G. and other nitro powders. This improvement was
effected by a reduction of the barium nitrate and the use of nitro-
cellulose of a higher degree of nitration, and also more gelatinisation in
manufacture. The granules are very hard, and resist moisture to an extent
hitherto unattainable by any "bulk" powder.

Irregularities of pressure in loading have also a minimum effect by reason
of the hardness of the grains. The colouring matter used is aurine, and
the small quantity of nitrate used is the barium salt. The powder is
standardised for pressure velocity with Boulenge chronograph,[A] pattern
and gravimetric density by elaborate daily tests, and is continually
subjected to severe trials for stability under various conditions of
storage, the result being that it may be kept for what in practice amount
to indefinite periods of time, either in cartridges or in bulk without any
alteration being feared. The E.C. powders are used in sporting guns. No. 1
and No. 2 E.C. are not at present manufactured, E.C. No. 3 having taken
their place entirely. Since 1890 these powders have been manufactured
under the Borland-Johnson patents, these improved powders being for some
time known as the J.B. powders. The E.C. No. 1 was superseded by the E.C.
No. 2, made under the Borland-Johnson patents, and this in its turn by the
E.C. No. 3 (in 1897).

[Footnote A: Invented in 1869 by Major Le Boulenge, Belgian Artillery. It
is intended to record the mean velocity between any two points, and from
its simplicity and accuracy is largely employed. Other forms have been
invented by Capt. Breger, French Artillerie de la Marine, and Capt.
Holden, R.A.]

~Indurite~ is the invention of Professor C.E. Munroe, of the U.S. Naval
Torpedo Station. It is made from insoluble nitro-cotton, treated in a
particular manner by steam, and mixed with nitro-benzene. The _Dupont_
powder is very similar to _Indurite_. M.E. Leonard, of the United States,
invented a powder consisting of 75 parts of nitro-glycerine, 25 parts of
gun-cotton, 5 parts of lycopodium powder, and 4 parts of urea crystals
dissolved in acetone. The French smokeless powder, Vielle poudre (poudre
B), used in the Lebel rifle, is a mixture of nitro-cellulose and tannin,
mixed with barium and potassium nitrates. It gives a very feeble report,
and very little bluish smoke. The Nobel Company is said to be perfecting a
smokeless powder in which the chief ingredients are nitro-amido- and tri-
nitro-benzene. C.O. Lundholm has patented (U.S. Pat, 701,591, 1901) a
smokeless powder containing nitro-glycerine 30, nitro-cellulose 60, diamyl
phthalate 10 (or diamyl phthalate 5, and mineral jelly 5). The diamyl
phthalate is added, with or without the mineral jelly to nitro-glycerine
and nitro-cellulose.

~Walsrode Powder.~--The smokeless powder known as Walsrode powder consists
of absolutely pure gelatinised nitro-cellulose, grained by a chemical not
a mechanical process, consequently the grains do not need facing with
gelatine to prevent their breaking up, as is the case with many nitro
powders. For this same reason, as well as from the method of getting rid
of the solvent used, the Walsrode has no tendency whatever to absorb
moisture. In fact, it can lie in water for several days, and when taken
out and dried again at a moderate temperature will be found as good as
before. Nor is it influenced by heat, whether dry or damp, and it can be
stored for years without being in the least affected. It is claimed also
that it heats the barrels of guns much less than black powder, and does
not injure them.

The standard charge is 30 grains, and it is claimed that with this charge
Walsrode powder will prove second to none. A large cap is necessary, as
the grains of this powder are very hard, and require a large flame to
properly ignite them. In loading cartridges for sporting purposes, an
extra felt wad is required to compensate for the small space occupied by
the charge; but for military use the powder can be left quite loose. The
gas pressure of this powder is low (in several military rifles only one-
half that of other nitros), and the recoil consequently small; and it is
claimed that with the slight increase of the charge (from 29 to 30 grs.)
both penetration and initial velocity will be largely increased, whilst
the gas pressure and recoil will not be greater.

This powder was used at Bisley, at the National Rifle Association's
Meeting, with satisfactory results. It is made by the Walsrode Smokeless
and Waterproof Gunpowder Company. The nitro-cotton is gelatinised by means
of acetic ether, and the skin produced retards burning. The nitro-cotton
is mixed with acetic ether, and when the gelatinisation has taken place,
the plastic mass is forced through holes in a metal plate into strips,
which are then cut up into pieces the size of grains. The M.H. Walsrode
powder is a leaflet powder, light in colour, about 40 grains of which give
a muzzle velocity of 1,350 feet and a pressure of 3 tons. It is, like the
other Walsrode powders, waterproof and heat-proof.

~Cooppal Powder~ is manufactured by Messrs Cooppal & Co. at their
extensive powder works in Belgium. It consists of nitro-jute or nitro-
cotton, with or without nitrates, treated with a solvent to form a
gelatinised mass. There are a great many varieties of this powder. One
kind is in the form of little squares; another, for use in Hotchkiss guns,
is formed into 3-millimetre cubes, and is black. Other varieties are
coloured with aniline dyes of different colours.

~Amberite~ is a nitro-cellulose powder of the 42-grain type of sporting
gunpowders, and is manufactured by Messrs Curtis's & Harvey Limited, at
their Smokeless Powder Factory, Tonbridge, Kent. It consists of a mixture
of nitro-cellulose, paraffin, barium, nitrate, and some other ingredients.
It is claimed for this powder that it combines hard shooting with safety,
great penetration, and moderate strain on the gun. It is hard and tough in
grain, and may be loaded like black powder, and subjected to hard friction
without breaking into powder, that it is smokeless, and leaves no residue
in the gun. The charge for 12 bores is 42 grains by weight, and 1-1/8 oz.
or 1-1/16 oz. shot. The powders known as cannonite[A] and ruby powder,
also manufactured by Messrs Curtis's & Harvey Limited, are analogous
products having the same general characteristics.

[Footnote A: For further details of cannonite, see First Edition, p. 181.]

~Smokeless Diamond~, also manufactured by the above mentioned firm, is a
nitro-cellulose powder of the 33-grain type of sporting gunpowders. It was
invented by Mr H.M. Chapman. The manufacture of Smokeless Diamond, as
carried out at Tonbridge, is shortly as follows:--The gun-cotton, which is
the chief ingredient of this powder, is first stoved, then mixed with
certain compounds which act as moderators, and after the solvents are
added, is worked up into a homogeneous plastic condition. It then
undergoes the processes of granulation, sifting, dusting, drying, and
glazing. In order to ensure uniformity several batches are blended
together, and stored for some time before being issued for use.

It is claimed for this powder that it is quick of ignition, the quickness
being probably due to the peculiar structure of the grains which, when
looked at under the microscope, have the appearance of coke. The charge
for a 12 bore is 33 grains and 1-1/16 oz. shot, which gives a velocity of
1,050 feet per second, and a pressure of 3 tons per square inch.

~Greiner's Powder~ consists of nitro-cellulose, nitro-benzol, graphite,
and lampblack.

~B.N. Powder.~--This powder is of a light grey or drab colour, perfectly
opaque, and rough to the touch. It consists of a mixture, nitro-cellulose
and the nitrates of barium and potassium. Its composition is as follows:--

Insoluble nitro-cellulose 29.13 parts
Soluble nitro-cellulose 41.31 "
Barium nitrate 19.00 "
Potassium nitrate 7.97 "
Sodium carbonate 2.03 "
Volatile matter 1.43 "

This powder is a modification of the Poudre B., or Vieille's powder
invented for use in the Lebel rifle, and which consisted of a mixture of
the nitro-celluloses with paraffin.

~Von Foster's Powder~ contains nothing but pure gelatinised nitro-
cellulose, together with a small quantity of carbonate of lime.

The German ~Troisdorf Powder~ is a mixture of gelatinised nitro-cellulose,
with or without nitrates.

~Maximite~ is the invention of Mr Hudson Maxim, and is a nitro-compound,
the base being gun-cotton. The exact composition and method of manufacture
are, however, kept secret. It is made by the Columbia Powder Manufacturing
Company, of New York, and in two forms--one for use as a smokeless rifle
powder, and the other for blasting purposes.

~Wetteren Powder.~--This powder was manufactured at the Royal Gunpowder
Factory at Wetteren, and used in the Belgian service. Originally it was a
mixture of nitro-glycerine and nitro-cellulose, with amyl acetate as
solvent. Its composition has, however, been altered from time to time. One
variety consists chiefly of nitro-cellulose, with amyl acetate as solvent.
It is of a dark brown colour, and of the consistency of indiarubber. It is
rolled into sheets and finally granulated.

~Henrite~ is a nitro-cellulose powder.

~Normal Powder.~--The Swedish powder known as "Normal" Smokeless Powder,
and manufactured by the Swedish Powder Manufacturing Company, of
Landskrona, Sweden, and used for some years past in the Swiss Army, is
made in four forms. For field guns of 8.4 calibre, it is used in the form
of cylindrical grains of a yellow colour, of a diameter of .8 to .9 mm.
and density of .790--about 840 grains of it go to one gun. For rifles, it
is used in the form of grey squares, density .750, and 1 grm. equals about
1,014 grains. One hundred rounds of this powder, fired in eighteen
minutes, raised the temperature of the gun barrel 284 deg. F. A nitro-
glycerine powder, fired under the same conditions, gave a temperature of
464 deg. F.

This powder is said to keep well--a sample kept 3-1/2 years gave as good
results as when first made--is easy to make, very stable, ignites easily,
not very sensitive to shock or friction, is very light, &c. Eight hundred
rounds fired from a heavy gun produced no injury to the interior of the
weapon. Samples kept for eleven months in the moist atmosphere of a
cellar, when fired gave a muzzle velocity of 1,450 ft. secs. and pressure
of 1,312 atmospheres, and the moisture was found to have risen from 1.2 to
1.6 per cent. After twenty-three months in the damp it contained 2 per
cent. moisture, gave a muzzle velocity of 1,478 ft. sees., and pressure of
1,356 atmospheres. In a 7.5 millimetre rifle, 13.8 grm. bullet, and charge
of 2 grms., it gives a muzzle velocity of 2,035 ft. secs. and a pressure
of 2,200 atmospheres. In the 8.4 cm. field-gun, with charge of 600 grms.,
and projectile of 6.7 kilogrammes, muzzle velocity was equal to 1,640 ft.
secs. and pressure 1,750. A sample of the powder for use in the .303 M.
rifle, lately analysed by the author, gave the following result:--

Gun-cotton 96.21 per cent.
Soluble cotton 1.80 "
Non-nitrated cotton trace.
Resin and other matters 1.99 "
_______

100.00

The various forms of powder invented and manufactured by Mr C.F. Hengst
are chiefly composed of nitrated straw that has been finely pulped. The
straw is treated first with acids and afterwards with alkalies, and the
result is a firm fibrous substance which is granulated. It is claimed that
this powder is entirely smokeless and flameless, that it does not foul the
gun nor heat the barrel, and is at the same time 150 per cent. stronger
than black powder.

The German "Troisdorf" powder consists of nitro-cellulose that has been
gelatinised together with a nitrate. Kolf's powder is also gelatinised
with nitro-cellulose. The powders invented by Mr E.J. Ryves contain nitro-
glycerine, nitro-cotton, castor-oil, paper-pulp, and carbonate of
magnesia. Maxim powder contains both soluble and insoluble nitro-
cellulose, nitro-glycerine, and carbonate of soda. The smokeless powder
made by the "Dynamite Actiengesellschaft Nobel" consists of nitro-starch
70 to 99 parts, and of di- or tri-nitro-benzene 1 to 30 parts.

An American wood powder, known as Bracket's Sporting Powder, consists of
soluble and insoluble nitro-lignine, mixed with charred lignine, humus,
and nitrate of soda. Mr F.H. Snyder, of New York, is the inventor of a
shell powder known as the "Snyder Explosive," consisting of 94 per cent.
nitro-glycerine, 6 per cent. of soluble nitro-cotton, and camphor, which
is said to be safe in use. Experiments were made with it in a 6-inch
rifled gun, fired at a target 220 yards away, composed of twelve 1-inch
steel plates welded together, and backed with 12-inch and 14-inch oak
beams, and weighing 20 tons. The shots entirely destroyed it. The charge
of explosive used was 10 lbs. in each shell.

~Comparative Tests of Black and Nitro Powders, from "American Field."~--
The results given in table below were obtained at the German Shooting
Association's grounds at Coepenick, Berlin. Penetration was calculated by
placing frames, each holding five cards of 1 millimetre in thickness
(equals .03937 inch), and 3 inches apart, in a bee-line, at distances of
20 inches. Velocity, pattern, and penetration were taken at 40 yards from
the muzzle of a 12-gauge choke-bore double-barrel gun. Gas pressure was
taken by a special apparatus. All shells were loaded with 1-1/8 oz. of No.
3 shot, equal to 120 pellets, and the number given below represents the
average number in the 30-inch pattern. The number of sheets passed through
gives the average penetration. One atmosphere equals pressure equal to 1
kilogramme (2.2 lbs.) on the square centimetre, hence 1,000 atmospheres
equal 2,200 lbs. on the square centimetre. The E.C., Schultze, and
Walsrode powders were loaded in Elcy's special shells, 2-1/2 inches long.
The averages were taken from a large number of shots, and the same series
of shots fired under precisely the same conditions.

_______________________________________________________________________
| | | | | |
| | Gas | | | |
| | Pressure. | Velocity. | Pattern. | Penetration. |
|__________________|____________|___________|____________|______________|
| | | | | |
| |Atmospheres.| Metres. | | Sheets. |
| | | | | |
|Fine-grained black| | | | |
|powder, standard | | | | |
|charge | 514.2 | 280 | 78.6 = 66% | 19.O |
| | | | | |
|Coarse-grained | | | | |
|black powder, | | | | |
|standard charge | 473.4 | 281.4 | 78.2 = 65% | 19.4 |
| | | | | |
|Schultze powder, | | | | |
|42 grains | 921.0 | 290.0 | 64.2 = 54% | 20.2 |
| | | | | |
|Schultze powder, | | | | |
|45 grains | 1052.8 | 305.8 | 52.2 = 42% | 20.6 |
| | | | | |
|E.G. smokeless, | | | | |
|42 grains | 920.2 | 298.4 | 81.4 = 67% | 18.8 |
| | | | | |
|Walsrode, | | | | |
|29 grains | 586.4 | 280.6 | 83.0 = 69% | 19.0 |
|__________________|____________|___________|____________|______________|

Barometer, 760 mm. Thermometer, 30 deg. C. Hydrometer = 65. Wind, S.W.

~Picric Powders.~--The chief of these is _Melinite_, the composition of
which is not known with certainty. It is believed to be melted picric acid
together with gun-cotton dissolved in acetone or ether-alcohol. Walke
gives the following proportions--30 parts of tri-nitro-cellulose dissolved
in 45 parts of ether-alcohol (2 to 1), and 70 parts of fused and
pulverised picric acid. The ether-alcohol mixture is allowed to evaporate
spontaneously, and the resulting cake granulated. The French claim,
however, that the original invention has been so modified and perfected
that the melinite of to-day cannot be recognised in the earlier product.
Melinite has a yellow colour, is almost without crystalline appearance,
and when ignited by a flame or heated wire, it burns with a reddish-yellow
flame, giving off copious volumes of black smoke. Melinite as at present
used is said to be a perfectly safe explosive, both as regards
manufacture, handling, and storage.

_Lyddite_,[A] the picric acid explosive used in the British service, is
supposed to be identical with the original melinite, but its composition
has not been made public.

[Footnote A: Schimose, the Japanese powder, is stated to be identical with
Lyddite and Melinite (_Chem. Centr._, 1906, 1, 1196).]

Picrates are more often used than picric acid itself in powders. One of
the best known is _Brugere's Powder_, which is a mixture of 54 parts of
picrate of ammonia and 45 parts of saltpetre. It is stable and safe to
manufacture. It has been used in the Chassepot rifle with good results,
gives little smoke, and a small residue only of carbonate of potash.

The next in importance is _Designolle's Powder_, made at Bouchon,
consisting of picrate of potash, saltpetre, and charcoal. It was made in
three varieties, viz., for rifles, big guns, and torpedoes and shells.
These powders are made much in the same way as gunpowder. The advantages
claimed for them over gunpowder are, greater strength, comparative absence
of smoke, and freedom from injurious action on the bores of guns.

_Emmensite_ is the invention of Dr Stephen Emmens, of the United States.
The Emmens "crystals" are produced by treating picric acid with fuming
nitric acid of specific gravity of 1.52. The acid dissolves with the
evolution of red fumes. The liquid, when cooled, deposits crystals, stated
to be different to picric acid, and lustrous flakes. These flakes, when
heated in water, separate into two new bodies. One of these enters into
solution and forms crystals unlike the first, while the other body remains
undissolved. The acid crystals are used mixed with a nitrate.

Emmensite has been subjected to experiment by the direction of the U.S.
Secretary for War, and found satisfactory. A sample of Emmensite, in the
form of a coarse powder, was first tried in a pistol, and proved superior
in propelling power to ordinary gunpowder. When tested against explosive
gelatine, it did very good work in shattering iron plates. It is claimed
for this explosive that it enjoys the distinction of being the only high
explosive which may be used both for firearms and blasting. This view is
supported by the trials made by the American War Office authorities, and
shows Emmensite to be a useful explosive both for blasting and as a
smokeless powder. Its explosive power, as tested, is 283 tons per square
inch, and its specific gravity is 1.8.

Abel proposed to use picric acid for filling shells. His _Picric Powder_
consisted of 3 parts of saltpetre, and 2 of picrate of ammonia.
_Victorite_ consists of chlorate of potash, picric acid, and olive oil,
and with occasionally some charcoal. It has the form of a coarse yellowish
grey powder, and leaves an oily stain on paper, and it is very sensitive
to friction and percussion. The composition is as follows:--KClO_{3} = 80
parts; picric acid, 110 parts; saltpetre, 10 parts; charcoal, 5 parts. It
is not manufactured in England. _Tschiner's Powder_ is very similar to
Victorite in composition, but contains resin. A list of the chief picric
powders will be found in the late Colonel J.P. Cundill, R.A.'s "Dictionary
of Explosives."

CHAPTER VII.

_ANALYSIS OF EXPLOSIVES._

Kieselguhr Dynamite--Gelatine Compounds--Tonite--Cordite--Vaseline--
Acetone--Scheme for Analysis of Explosives--Nitro-Cotton--Solubility Test--
Non-Nitrated Cotton--Alkalinity--Ash and Inorganic Matter--Determination
of Nitrogen--Lunge, Champion and Pellet's, Schultze-Tieman, and Kjeldahl's
Methods--Celluloid--Picric Acid and Picrates--Resinous and Tarry Matters--
Sulphuric Acid and Hydrochloric Acid and Oxalic Acid--Nitric Acid--
Inorganic Impurities--General Impurities and Adulterations--Potassium
Picrate, &c.--Picrates of the Alkaloids--Analysis of Glycerine--Residue--
Silver Test--Nitration--Total Acid Equivalent--Neutrality--Free Fatty
Acids--Combined Fatty Acids--Impurities--Oleic Acid--Sodium Chloride--
Determination of Glycerine--Waste Acids--Sodium Nitrate--Mercury
Fulminate--Cap Composition--Table for Correction of Volumes of Gases, for
Temperature and Pressure

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