Dr Will's apparatus has been modified by Dr Robertson,[A] of the Royal Gunpowder Factory, Waltham Abbey. The form of the apparatus used by him is shown in Fig. 51.
~CO_{2} Holders.~—Although objection has been taken to the use of compressed CO_{2} in steel cylinders on account of the alleged large and variable amount of air present, it has, nevertheless, been found possible to obtain this gas with as little as 0.02 per cent. of air. Frequent estimations of the air present in the CO_{2} of a cylinder show that even with the commercial article, after the bulk of the CO_{2} has been removed, the residual gas contains only a very small amount of air, which decreases in a gradual and perfectly regular manner. For example, one cylinder which gave 0.03 per cent. of air by volume, after three months' constant use gave 0.02 per cent. The advantage of using CO_{2} from this source is obvious when compared with the difficulty of evolving a stream of gas of constant composition from a Kipps or Finkener apparatus. A micrometer screw, in addition to the main valve of the CO_{2} cylinder, is useful for governing the rate of flow. A blank experiment should be made to ascertain the amount of air in the CO_{2} and the correction made in the readings afterwards.
[Footnote A: Jour. Soc. Chem. Ind., June 30, 1902, p. 819.]
[Illustration: Fig 51.—Will's Apparatus for Testing Nitro-cellulose]
~Measurement of Pressure and Rate of Flow.~—Great attention is paid to the measurement of the rate of flow of gas, which is arrived at by counting with a stop-watch the number of bubbles of gas per minute in a small sulphuric acid wash bottle. A mercury manometer is introduced here, and is useful for detecting a leak in the apparatus. The rate of flow that gives the most satisfactory results is 1,000 c.c. per hour. If too rapid it does not become sufficiently preheated in the glass spiral, and if too slow there is a more rapid decomposition of the nitro-cellulose by the oxides of nitrogen which are not removed.
~Decomposition Tube.~—This is of the form and dimensions given by Dr Will (15 mm. wide and 10 cm. high), the preheating worm being of the thinnest hydrometer stem tubing. The ground-in exit tube is kept in position by a small screw clamp with trunnion bearings.
~Bath.~—To permit of two experiments being carried on simultaneously, the bath is adapted for two decomposition tubes, and is on the principle of Lothar Meyer's air bath, that is, the bath proper filled with a high- flashing hydrocarbon oil, and fitted with a lid perforated with two circular holes for the spiral tubes, is surrounded by an asbestos-covered envelope, in the interior of which circulate the products of combustion of numerous small gas jets. The stirrer, agitated by a water motor, or, better still, a hot-air engine, has a series of helical blades curved to give a thorough mixing to the oil. Great uniformity and constancy of temperature are thus obtained. The bath is fitted also with a temperature regulator and thermometer.
~Reduction Tube~—This is of copper, and consists of two parts, the outer tube and an inner reaching to nearly the bottom of the former. Into the inner tube fits a spiral of reduced copper gauze, and into the annular space between the tubes is fitted a tightly packed reduced copper spiral. At the bottom the inlet tube dips into a layer of copper oxide asbestos, on the top of which is a layer of reduced copper asbestos. Through the indiarubber cork passes a glass tube, which leads the CO_{2} and nitrogen out of the reduction tube. As the portion of the tube containing the spirals is heated to redness, water jackets are provided on both inner and outer tubes to protect the indiarubber cork.
~Nitrogen Measuring Apparatus.~—The measuring tube with zigzag arrangement is used, having been found very economical in potash. It is most convenient to take readings by counterbalancing the column of potash solution and reading off the volume of gas at atmospheric pressure. For this purpose the tap immediately in front of the measuring tube is momentarily closed, this having been proved to be without ill effect on the progress of the test. In all experiments done by this test the air correction is subtracted from each reading, and the remainder brought to milligrams of nitrogen with the usual corrections. As objection has frequently been taken to the test on the ground of difficulty in interpreting the results obtained, Dr Robertson made a series of experiments for the purpose of standardising the test, and at the same time of arriving at the condition under which it could be applied in the most sensitive and efficient manner. A variety of nitro-celluloses having been tested, there were chosen as typical, of stable and unstable products, service gun-cotton on the one hand, and an experimental gun- cotton, Z, on the other. The first point brought out by these experiments was the striking uniformity of service gun-cotton, first in regard to the rectilinear nature of the curve of evolution of nitrogen, and secondly in regard to the small range within which a large number of results is included, 15 samples lying between 6.6 and 8.7 mgms. of nitrogen evolved in four hours. In the case of service gun-cotton, little difference in the rate of evolution of nitrogen evolved is obtained on altering the rate of passage of CO_{2} gas through the wide range of 500 c.c. per hour to 2,500 c.c. per hour. With Z gun-cotton (see Fig. 52), however, the case is very different. Operating at a rate of 1,000 c.c. of CO_{2} per hour, a curve of nitrogen evolution is obtained, which is bent and forms a good representation of the inherent instability of the material as proved to exist from other considerations. Operating at the rate of 1,500 c.c. per hour, as recommended by Dr Will, the evolution of nitrogen is represented by a straight line, steeper, however, than that of service gun-cotton. The rate of passage of CO_{2} was therefore chosen at 1,000 c.c. per hour, or two-thirds of the rate of Dr Will, and this rate, besides possessing the advantage claimed of rendering diagnostic the manner of nitrogen evolution in Z gun-cotton, has in other cases been useful in bringing out relationships, which the higher rate would have entirely masked.
[Illustration: Fig. 52.—Dr. Robertson's results.]
[Illustration: Fig. 53.—Service Guncotton for Cordite made at a Private
Factory.]
Readings are taken thirty minutes from the time the nitro-cellulose is heated, and are taken at intervals of fifteen minutes for about four hours; fresh caustic potash is added every thirty minutes or so. It is convenient to plot the results in curves. The curves given in Fig. 53 are from gun-cotton manufacturers in England at a private factory. The rate of evolution of nitrogen is as follows:—
In 1 hour. In 2 hours. In 3 hours. In 4 hours. N. N. N. N. in milligrammes. 1.25 2.55 4.5 5.75 1.5 3.25 5.25 6.75 These results are very satisfactory, the gun-cotton was of a very good quality. Several hours are necessary to remove all the air from the apparatus. Dr Will stated fifteen minutes in his original paper, but this has not been found sufficient. It has not been satisfactorily proved that Will's test can be applied to gelatinised nitro-cellulose powders. It is convenient to plot the results in curves; the nitrogen is generally given in cubic centimetres or in milligrammes, and readings taken every fifteen minutes. The steepness of the curve is a measure of the stability of the nitro-cellulose which is being examined. The steeper the curve the more nitrogen is evolved per unit of time, and the less stable the nitro- cellulose. In the case of unstable nitro-celluloses heated under the conditions described, the separation of nitrogen is much greater at first than at a later period. If the nitro-cellulose be very unstable, explosions are produced. If the separation of nitrogen is uniform during the prolonged heating, then the nitro-cellulose may be regarded as "normal." If it be desired to determine the absolute amount of nitrogen separated from a nitro-cellulose, the following conditions must be observed:—(1.) Accurate weighing of the nitro-cellulose; (2.) Determination of the amount of air in the CO_{2}, and deduction of this from the volume of gas obtained; (3.) Reduction of the volume of the gas to the volume at 0° C. and 760 mm. pressure.[A]
[Footnote A: See also Jour. Soc. Chem. Ind., Dec. 1902, pages 1545-1555, on the "Stability of Nitro-cellulose" and "Examination of Nitro- cellulose," Dr Will.]
~Bergrnann and Junk~[A] describe a test for nitro-cellulose that has been in use in the Prussian testing station for some years. The apparatus consists of a closed copper bath provided with a condenser and 10 countersunk tubes of 20 cm. length. By boiling amyl-alcohol in the bath, the tubes can be kept at a constant temperature of 132° C. The explosive to be tested is placed in a glass tube 35 cm. long and 2 cm. wide, having a ground neck into which an absorption bulb is fitted. The whole apparatus is surrounded by a shield, in case of explosion. In carrying out the test, 2 grms. of the explosive are placed in the glass tube and well pressed down. The absorption bulb is half filled with water, and fitted into the ground neck of the glass tube, which is then placed in one of the tubes in the bath previously brought to the boiling point (132° C.). The evolved oxides of nitrogen are absorbed in the water in the bulb, and at the end of two hours the tubes are removed from the bath, and on cooling, the water from the bulb flows back and wets the explosive. The contents of the tube are filtered and washed, the filtrate is oxidised with permanganate, and the nitrogen determined as nitric oxide by the Schultze-Tieman method. The authors conclude that a stable gun-cotton does not evolve more than 2.5 c.c. of nitric oxide per grm. on being heated to 132° C. for two hours, and a stable collodion-cotton not more than 2 c.c. under the same conditions. The percentage of moisture in the sample to be tested should be kept as low as possible. A sample of nitro-cellulose containing 1.97% of moisture gave an evolution of 2.6 c.c. per grm., while the same sample with 3.4% moisture gave an evolution of over 50 c.c. per grm. Sodium carbonate added to an unstable nitro-cellulose diminishes the rate of decomposition, but if sodium carbonate be intimately mixed with a stable nitro-cellulose the rate of decomposition will be increased. Calcium carbonate and mercury chloride have no influence. If an unstable nitro- cellulose be extracted with alcohol a stable compound is produced. The percentage solubility of a nitro-cellulose in ether-alcohol rises on heating to 132° C. A sample which before heating had a solubility of 4.7% had its solubility increased to 82.5% after six hours' heating.
[Footnote A: Jour. Soc. Chem. Ind., xxiii., Oct. 15, 1904, p. 953.]
Mr A.P. Sy (Jour. Amer. Chem. Soc., 1903) describes a new stability test for nitro-cellulose which he terms "The Elastic Limit of Powder Resistance to Heat." The test consists in heating the powder on a watch glass in an oven to a temperature of 115° C., after eight hours the watch glass and powder are weighed and the process repeated daily for six days or less. He claims that the powder is tested in its natural state, all the products of decomposition are taken into account, whilst in the old tests only the acid products are shown, and in the Will test only nitrogen, that it affords an indication of the effect of small quantities of added substances or foreign matters on the stability and that it is simple, and not subject to the variations of the old tests.
Obermüller (Jour. Soc. Chem. Ind., April 15, 1905) considers Bergmann and Junk's test is too complicated and occupies too much time; he proposes to heat gun-cotton to 140° C. in vacuo, and to measure continuously by means of a mercury manometer the pressure exerted by the evolved gases, the latter being maintained at constant volume; the rate at which the pressure increases is a measure of the rate of decomposition of the nitro- cellulose.
SPECIFIC GRAVITIES OF EXPLOSIVES, &C.
Nitro-glycerine 1.6
Gun-cotton (dry) 1.06
" (25 per cent. water) 1.32
Dynamite No. 1 1.62
Blasting gelatine 1.54
Gelatine dynamite 1.55
Ballistite 1.6
Forcite 1.51
Tonite 1.28
Roburite 1.40
Bellite 1.2-1.4
Carbo-dynamite 1.5
Turpin's cast picric acid 1.6
Nitro-mannite 1.6
Nitro-starch 1.5
Emmensite 1.8
Mono-nitro-benzene 1.2
Meta-di-nitro-benzene 1.575 at 18° C.
Ortho-di-nitro-benzene 1.590 "
Para-di-nitro-benzene 1.625 "
British gunpowder, E.X.E. 1.80
" " S.B.C. 1.85
Cannonite (powder) 1.60
Celluloid 1.35
Cellulose 1.45
Ammonium nitrate 1.707
Mercury fulminate 4.42
TABLE OF THE TEMPERATURE OF DETONATION.
Blasting gelatine 3220°
Nitro-glycerine 3170°
Dynamite 2940°
Gun-cotton 2650°
Tonite 2648°
Picric acid 2620°
Roburite 2100°
Ammonia nitrate 1130°
RELATIVE SENSITIVENESS TO DETONATION (by Professor C.E. Munroe, U.S. Naval
Torpedo Station).
__________________________________________________________________________ | | Maximum | | Distance | | at which | | Detonation | | occurred. | | CM. | | | Gun-cotton | 10 | Nitro-glycerine 86.5 nitro-cotton | | 9.5, camphor 4 per cent. Explosive gelatine | 20 | NH_{4}NO_{3} 5 parts, (camphorated) | | C_{6}H_{4}(N0_{3}){2} 1 part. Judson powder, R.R.P. | 25 | Emmensite (No. 259) | 30 | Rack-a-rock | 32 | KClO{3} 79 parts, | | C_{6}H_{5}(NO)_{2} 21 parts. Bellite | 50 | Forcite No. 1 | 61 | Kieselguhr dynamite No. 1 | 64 | 75 per cent. nitro-gycerine. Atlas powder No. 1 | 74 | __________________________|____________|_________________________
CHAPTER IX.
DETERMINATION OF THE RELATIVE STRENGTH OF EXPLOSIVES.
Effectiveness of an Explosive—High and Low Explosives—Theoretical
Efficiency—MM. Roux and Sarrau's Results—Abel and Noble's—Nobel's
Ballistic Test—The Mortar, Pressure, or Crusher Gauge—Lead Cylinders—
The Foot-Pounds Machine—Noble's Pressure Gauge—Lieutenant Walke's
Results—Calculation of Pressure Developed by Dynamite and Gun-Cotton—
Macnab's and Ristori's Results of Heat Developed by the Explosion of
Various Explosives—Composition of some of the Explosives in Common Use
for Blasting, &c.
~The Determination of the Relative Strength of Explosives.~—Explosives may be roughly divided into two divisions, viz., those which when exploded produce a shattering force, and those which produce a propulsive force. Explosives of the first class are generally known as the high explosives, and consist for the most part of nitro compounds, or mixtures of nitro compounds with other substances. Any explosive whose detonation is very rapid is a high explosive, but the term has chiefly been applied to the nitro-explosives.
The effectiveness of an explosive depends upon the volume and temperature of the gases formed, and upon the rapidity of the explosion. In the high explosives the chemical transformation is very rapid, hence they exert a crushing of shattering effect. Gunpowder, on the other hand, is a low explosive, and produces a propelling or heaving effect.
The maximum work that an explosive is capable of producing is proportionate to the amount of heat disengaged during its chemical transformation. This may be expressed in kilogrammetres by the formula 425Q, where Q is the number of units of heat evolved. The theoretical efficiency of an explosive cannot, however, be expected in practice for many reasons.
In the case of blasting rock, for instance:[A]—1. Incomplete combustion of the explosive. 2. Compression and chemical changes induced in the surrounding material operated on. 3. Energy expended in the cracking and heating of the material which is not displaced. 4. The escape of gas through the blast-hole, and the fissures caused by the explosion. The proportion of useful work has been estimated to be from 14 to 33 per cent. of the theoretical maximum potential.
[Footnote A: C.N. Hake, Government Inspector of Explosives, Victoria, Jour. Soc. Chem. Ind., 1889.]
For the purposes of comparison, manufacturers generally rely more upon the practical than the theoretical efficiency of an explosive. These, however, stand in the same relation to one another, as the following table of Messrs Roux and Sarrau will show:—
MECHANICAL EQUIVALENT OF EXPLOSIVES.
Theoretical Work Relative
in Kilos. Value.
Blasting powder (62 per cent. KNO_{3}) 242,335 1.0
Dynamite (75 per cent. nitro-glycerine) 548,250 2.26
Blasting gelatine (92 per cent. nitro-glycerine) 766,813 3.16
Nitro-glycerine 794,563 3.28
Experiments made in lead cylinders give—
Dynamite 1.0
Blasting gelatine 1.4
Nitro-glycerine 1.4
Sir Frederick Abel and Captain W.H. Noble, R.A., have shown that the maximum pressure exerted by gunpowder is equal to 486 foot-tons per lb. of powder, or that when 1 kilo, of the powder gases occupy the volume of 1 litre, the pressure is equal to 6,400 atmospheres; and Berthelot has calculated that every gramme of nitro-glycerine exploded gives 1,320 units of heat. MM. Roux and Sarrau, of the Depôt Centrales des Poudres, Paris, by means of calorimetric determinations, have shown that the following units of heat are produced by the detonation of—
Nitro-glycerine 1,784 heat units.
Gun-cotton 1,123 "
Potassic picrate 840 "
which, multiplied by the mechanical equivalent per unit, gives—
Nitro-glycerine 778 metre tons per kilogramme.
Gun-cotton 489 " "
Picrate of potash 366 " "
~Nobel's Ballistic Test.~—Alfred Nobel was the first to make use of the mortar test to measure the (ballistic) power of explosives. The use of the mortar for measuring the relative power of explosives does not give very accurate results, but at the same time the information obtained is of considerable value from a practical point of view. The mortar consists of a solid cylinder of cast iron, one end of which has been bored to a depth of 9 inches, the diameter of the bore being 4 inches. At the bottom of the bore-hole is a steel disc 3 inches thick, in which another hole has been bored 3 inches by 2 inches. The mortar (Fig. 54) itself is fitted with trunnions, and firmly fixed in a very solid wooden carriage, which is securely bolted down to the ground. The shot used should weigh 28 lbs., and be turned accurately to fit the bore of the mortar. Down its centre is a hole through which the fuse is put.
The following is the method of making an experiment:—A piece of hard wood is turned in the lathe to exactly fit the hole in the steel disc at the bottom of the bore. This wooden cylinder itself contains a small cavity into which the explosive is put. Ten grms. is a very convenient quantity. Before placing in the mortar, a hole may be made in the explosive by means of a piece of glass rod of such a size that the detonator to be used will just fit into it. After placing the wooden cylinder containing the explosive in the cavity at the bottom of the bore, the shot, slightly oiled, is allowed to fall gently down on to it. A piece of fuse about a foot long, and fitted with a detonator, is now pushed through the hole in the centre of the shot until the detonator is embedded in the explosive. The fuse is now lighted, and the distance to which the shot is thrown is carefully measured. The range should be marked out with pegs into yards and fractions of yards, especially at the end opposite to the mortar. The mortar should be inclined at an angle of 45°. In experimenting with this apparatus, the force and direction of the wind will be found to have considerable influence.
[Illustration: FIG. 54.—MORTAR FOR MEASURING THE BALLISTIC POWER OF
EXPLOSIVES. A, Shot; B, Steel Disc; C, Section of Mortar (Cast
Iron); D, Wooden Plug holding Explosive (E); F, Fuse.]
Mr T. Johnson made some ballistic tests. He used a steel mortar and a shot weighing 29 Ibs., and he adopted the plan of measuring the distance to which a given charge, 5 grms., would throw the shot. He obtained the following results:—
Range in Feet.
Blasting gelatine (90 per cent. nitro-glycerine and nitro-cellulose) 392
Ammonite (60 per cent. Am(NO_{3}) and 10 per cent. nitro-naphthalene) 310
Gelignite (60 per cent. nitro-gelatine and gun-cotton) 306
Roburite (AmNO_{3} and chloro-nitro-benzol) 294
No. 1 dynamite (75 per cent. nitro-gelatine) 264
Stonite (68 per cent. nitro-gelatine and 32 per cent. wood-meal) 253
Gun-cotton 234
Tonite (gun-cotton and nitrates) 223
Carbonite (25 per cent. nitro-gelatine, 40 per cent. wood-meal,
and 30 per cent. nitrates) 198
Securite (KNO_{3} and nitro-benzol) 183
Gunpowder 143
~Calculation of the Volume of Gas Evolved in an Explosive Reaction.~—The volume of gas evolved in an explosive reaction may be calculated, but only when they are simple and stable products, such calculations being made at 0° and 760 mm. Let it be required, for example, to determine the volume of gas evolved by 1 gram-molecule of nitro-glycerine. The explosive reaction of nitro-glycerine may be represented by the equation.
C_{3}H_{5}O_{3}(NO_{2}){3} = 3CO{2} + 2-1/2H_{2}O + 1-1/2N_{2} + 1/4O_{2}
By weight 227 = 132 + 45 + 42 + 8
By volume 2 = 3 + 2-1/2 + 1-1/2 + 1/4
The weights of the several products of the above reactions are calculated by multiplying their specific gravities by the weight of 1 litre of hydrogen at 0° C. and 760 mm. (0.0896 grm). Thus,
One litre of CO_{2} = 22 x .0896 = 1.9712 grm.
" H_{2}O = 9 x " = 0.8064 "
" N_{2} = 14 x " = 1.2544 "
" O_{2} = 16 x " = 1.4336 "
The volume of permanent gases at 0° and 760 mm. is constant, and assuming the gramme as the unit of mass, is found to be 22.32 litres. Thus:—
Volume of 44 of CO_{2}, at 0° and 760 mm. = 44/1.9712 = 22.32 litres. 18 " H_{2}O " " = 18/0.8044 = 22.32 " 28 " N_{2} " " = 28/1.2544 = 22.32 " 32 " O_{2} " " = 32/1.4366 = 22.32 "
Therefore
132 grms. of CO_{2} at 0° C and 760 mm. = 22.32 x 3 = 66.96 litres.
45 " H_{2}O " " = 22.32 x 2-1/2 = 55.80 "
42 " N_{2} " " = 22.32 x 1-1/2 = 33.48 "
8 " O_{2} " " = 22.32 x 1/4 = 5.58 "
____________
161.82 " Therefore 1 gram-molecule or 227 grms. of nitro-glycerine when exploded, produces 161.82 litres of gas at 0° C and 760 mm.
To determine the volume of gas at the temperature of explosion, we simply apply the law of Charles.[A] Thus—
V : V' :: T : T' or V' = VT'/T
in which V represents the original volume.
V' " new volume.
T " original temperature on the absolute scale.
T' " new temperature of the same scale
In the present case T' = 6001°.
Therefore substituting, we have
V' = 161.82x6001/273 = 3557 litres
or at the temperature of explosion 1 gram-molecule of nitro-glycerine produces 3,557 litres of permanent gas.
[Footnote A: According to the law of Charles, the volume of any gas varies directly as its temperature on the absolute scale, provided the pressure remains constant. Knowing the temperature on the centigrade scale, the corresponding temperature on the absolute scale is obtained by adding 273 to the degrees centigrade.]
~Pressure or Crusher Gauge.~—There are many forms of this instrument. As long ago as 1792 Count Rumford used a pressure gauge. The so-called crusher gauge was, however, first used by Captain Sir Andrew Noble in his researches on powder. Other forms are the Rodman[A] punch Uchatius Eprouvette, and the crusher gauge of the English Commission on Explosives. They are all based either upon the size of an indent made upon a copper disc by a steel punch fitted to a piston, acted upon by the gases of the explosive, or upon the crushing or flattening of copper or lead cylinders.
[Footnote A: Invented by General Rodman, United States Engineers.]
[Illustration: FIG. 55.—PRESSURE GAUGE.]
Berthelot uses a cylinder of copper, as also did the English Commission, but in the simpler form of apparatus mostly used by manufacturers lead cylinders are used. This form of apparatus (Fig. 55) consists of a base of iron to which four uprights a are fixed, set round the circumference of a 4-inch circle; the lead plug rests upon the steel base let into the solid iron block. A ring c holds the uprights d together at the top. The piston b, which rests upon the lead plug, is a cylinder of tempered steel 4 inches in diameter and 5 inches in length; it is turned away at the sides to lighten it as much as possible. It should move freely between the uprights d. In the top of this cylinder is a cavity to hold the charge of explosive. The weight of this piston is 12-1/4 lbs. The shot e is of tempered steel, and 4 inches in diameter and 10 inches in length, and weighs 34-1/2 lbs. It is bored through its axis to receive a capped fuse.
The instrument is used in the following manner:—A plug of lead 1 inch long and 1 inch in diameter, and of a cylindrical form, is placed upon the steel plate between the uprights a, the piston placed upon it, the carefully weighed explosive placed in the cavity, and the shot lowered gently upon the piston. A piece of fuse, with a detonator fixed at one end, is then pushed through the hole in the shot until it reaches the explosive contained in the cavity in the piston. The fuse is lighted. When the charge is exploded, the shot is thrown out, and the lead cylinder is more or less compressed. The lead plugs must be of a uniform density and homogeneous structure, and should be cut from lead rods that have been drawn, and not cast separately from small masses of metal.
[Illustration: FIG. 56.—b, STEEL PUNCH; c, LEAD CYLINDER FOR USE WITH
PRESSURE GAUGE.]
The strength of the explosive is proportional to the work performed in reducing the height of the lead (or copper) plug, and to get an expression for the work done it is necessary to find the number of foot-pounds (or kilogrammetres) required to produce the different amounts of compression. This is done by submitting exactly similar cylinders of lead to a crushing under weights acting without initial velocity, and measuring the reduced heights of the cylinders; from these results a table is constructed establishing empirical relations between the reduced heights and the corresponding weights; the cylinders are measured both before and after insertion in the pressure gauge by means of an instrument known as the micrometer calipers (Fig. 57).[A]
[Footnote A: An instrument called a "Foot-pounds Machine" has been invented by Lieut. Quinan, U.S. Army. It consists of three boards, connected so as to form a slide 16 feet high, in which a weight (the shot of the pressure gauge) can fall freely. One of the boards is graduated into feet and half feet. The horizontal board at the bottom, upon which the others are nailed, rests upon a heavy post set deep in the ground, upon which is placed the piston of the gauge, which in this case serves as an anvil on which to place the lead cylinders. The shot is raised by means of a pulley, fixed at the top of the structure, to any desired height, and let go by releasing the clutch that holds it. The difference between the original length and the reduced length gives the compression caused by the blow of the shot in falling, and gives the value in foot-pounds required to produce the different amounts of compression. (Vide Jour. U.S. Naval Inst., 1892.)]
[Illustration: FIG. 57.—MICROMETER CALIPERS FOR MEASURING DIAMETER OF
LEAD CYLINDERS.]
~The Use of Lead Cylinders.~—The method of using lead cylinders to test the strength of an explosive is a very simple affair, and is conducted as follows:—A solid cast lead cylinder, of any convenient size, is bored down the centre for some inches, generally until the bore-hole reaches to about the centre of the block. The volume of this hole is then accurately measured by pouring water into it from a graduated measure, and its capacity in cubic centimetres noted. The bore-hole is then emptied and dried, and a weighed quantity (say 10 grms.) of the explosive pressed well down to the bottom of the hole. A hole is then made in the explosive (if dynamite) with a piece of clean and rounded glass rod, large enough to take the detonator. A piece of fuse, fitted with a detonator, is then inserted into the explosive and lighted. After the explosion a large pear- shaped cavity will be found to have been formed, the volume of which is then measured in the same way as before.
The results thus obtained are only relative, but are of considerable value for comparing dynamites among themselves (or gun-cottons). Experiments in lead cylinders gave the relative values for nitro-glycerine 1.4, blasting gelatine 1.4, and dynamite 1.0. (Fig. 58 shows sections of lead cylinders before and after use.)
[Illustration: FIG. 58.—LEAD CYLINDERS BEFORE AND AFTER USE.]
Standard regulations for the preparation of lead cylinders may be found in the Chem. Zeit., 1903, 27 [74], 898. They were drawn up by the Fifth International Congress of App. Chem., Berlin. The cylinder of lead should be 200 mm. in height and 200 mm. in diameter. In its axis is a bore-hole, 125 mm. deep and 25 mm. in diameter. The lead used must be pure and soft, and the cylinder used in a series of tests must be cast from the same melt. The temperature of the cylinders should be 15° to 20° throughout. Ten grms. of explosive should be used and wrapped in tin-foil. A detonator with a charge of 2 grms., to be fired electrically, is placed in the midst of the explosive. The cartridge is placed in the bore-hole, and gently pressed against the bottom, the firing wires being kept in central position. The bore-hole is then filled with dry quartz sand, which must pass through a sieve of 144 meshes to the sq. cm., the wires being .35 mm. diameter. The sand is filled in evenly, any excess being levelled off. The charge thus prepared is then fired electrically. The lead cylinder is then inverted, and any residues removed with a brush. The number of c.c. of water required to fill the cavity, in excess of the original volume of the bore-hole, is a measure of the strength of the explosive. The results are only comparable if made with the same class of explosive. A result is to be the mean of at least three experiments. The accuracy of the method depends on (a) the uniform temperature of the lead cylinder (15° to 20° C. 7); (b) on the uniformity of the quartz sand; (c) on the uniformity of the measurements.
[Illustration: FIG. 59.—NOBLE'S PRESSURE GAUGE.]
~Noble's Pressure Gauge.~—The original explosive vessels used by Captain Sir A. Noble in his first experiments were practically exactly similar to those that he now employs, which consists of a steel barrel A (Fig. 59), open at both ends, which are closed by carefully fitted screw plugs, furnished with steel gas checks to prevent any escape past the screw. The action of the gas checks is exactly the same as the leathers used in hydraulic presses. The pressure of the gas acting on both sides of the annular space presses these sides firmly against the cylinder and against the plug, and so effectually prevents any escape. In the firing plug F is a conical hole closed by a cone fitting with great exactness, which, when the vessel is prepared for firing, is covered with fine tissue paper to act as an insulator. The two firing wires GG, one in the insulated cone, the other in the firing plug, are connected by a very fine platinum wire passing through a glass tube filled with meal powder. The wire becomes red-hot when connection is made with a Leclanché battery, and the charge which has previously been inserted into the vessel is fired. The crusher plug is fitted with a crusher gauge H for determining the pressure of the gases at the moment of explosion, and in addition there is frequently a second crusher gauge apparatus screwed into the cylinder. When it is desired to allow the gases to escape for examination, the screw J is slightly withdrawn. The gases then pass into the passage I, and can be led to suitable apparatus in which their volume can be measured, or in which they can be sealed for subsequent chemical analysis.
The greatest care must be exercised in carrying out experiments with this apparatus; it is particularly necessary to be sure that all the joints are perfectly tight before exploding the charge. Should this not be the case, the gases upon their generation will cut their way out, or completely blow out the part improperly secured, in either case destroying the apparatus. The effect produced upon the apparatus when the gas has escaped by cutting a passage for itself is very curious. The surface of the metal where the escape occurred presents the appearance of having been washed away in a state of fusion by the rush of the highly heated products.
~The Pressure Gauge.~—The pressure is found by the use of a little instrument known as the pressure gauge which consists of a small chamber formed of steel, inside of which is a copper cylinder, and the entrance being closed by a screw gland, in which a piston, having a definite sectional area, works. There is a gas check E (Fig. 60) placed in the gland, and over the piston, which prevents the admission of gas to the chamber. When it is desired to find the pressure in the chamber of a gun, one or more of these crushers are made up with or inserted at the extreme rear end of the cartridge, in order to avoid their being blown out of the gun when fired. This, however, often takes place, in which case the gauges are usually found a few yards in front of the muzzle. The copper cylinders which register the pressure are made 0.5 inch long from specially selected copper, the diameters being regulated to give a sectional area of either 1/12 or 1/24 square inch.
[Illustration: FIG. 60.—CRUSHER GAUGE. E, GAS CHECK.]
Hollow copper cylinders are manufactured with reduced sectional areas for measuring very small pressures. It has been found that these copper cylinders are compressed to definite lengths for certain pressures with remarkable uniformity. Thus a copper cylinder having a sectional area of 1/12 square inch, and originally 1/2 inch long, is crushed to a length of 0.42 inch by a pressure of 10 tons per square inch. By subsequently applying a pressure of 12 tons per square inch the cylinder is reduced to a length of 0.393 inch. Before using the cylinders, whether for experimenting with closed vessels or with guns, it is advisable to first crush them by a pressure a little under that expected in the experiment. Captain Sir A. Noble used in his experiments a modification of Rodman's gauge. (Ordnance Dept., U.S.A., 1861.)
~By Calculation.~—To calculate the pressure developed by the explosion of dynamite in a bore-hole 3 centimetres in diameter, charged with 1 kilogramme of 75 per cent. dynamite, Messrs Vieille and Sarrau employ the following formula:—
P = V_{o}(1 + Q/273.c)/(V - v).
Where V_{o} = the volume (reduced to 0° and 760 mm.) of the gases produced by a unit of weight of the explosive; Q the number of calories disengaged by a unit of weight of the explosive; c equals the specific heat at constant volume of the gases; V the volume in cubic centimetres of a unit of weight of the explosive; v the volume occupied by the inert materials of the explosive. The volume of gas produced by the explosion of 1 kilogramme of nitro-glycerine (at 0° and 760 mm.) is 467 litres.
V_{o} will therefore equal 0.75 x 467 = 350.25.
The specific heat c is, according to Sarrau, .220 (c); and according to Bunsen, 1 kilogramme of dynamite No. 1 disengages 1,290 (Q) calories. The density of dynamite is equal to 1.5, therefore
V = 1/1.5 = .666.
If we take the volume of the kieselguhr as .1, we find from above formula that
P = 350(1 + 1290/(273 x .222))/(.600 - .1) = 13,900 atmospheres,
which is equal to 14,317 kilogrammes per square centimetre. The pressure developed by 1 kilogramme of pure nitro-glycerine equals 18,533 atmospheres, equals 19,151 kilogrammes. Applying this formula to gun- cotton, and taking after Berthelot, Q = 1075, and after Vieille and Sarrau, V_{o} = 671 litres, and c as .2314, and the density of the nitro-cellulose as 1.5, we have (V = O)
P = 671(1 + 1075/(273 x .2314))/.666 = 18,135 atmospheres.
To convert this into pressure of kilogrammes per square centimetre, it is necessary to multiply it by the weight of a column of mercury 0.760 m. high, and 1 square centimetre in section, which is equal to increasing it by 1/30. It thus becomes
P^{k} = (1 + 1/30).
P^{k} = 18,135 x 1.033 = 18,733 kilogrammes.
The following tables, taken from Messrs William Macnab's and E. Ristori's paper (Proc. Roy. Soc., 56, 8-19), "Researches on Modern Explosives," are very interesting. They record the results of a large number of experiments made to determine the amount of heat evolved, and the quantity and composition of the gases produced when certain explosives and various smokeless powders were fired in a closed vessel from which the air had been previously exhausted. The explosions were carried out in a "calorimetric bomb" of Berthelot's pattern.[A]
[Footnote A: For description of "bomb," see "Explosives and their Power,"
Berthelot, trans. by Hake and Macnab, p. 150. (Murray.)]
Table Showing Quantity of Heat and Volume and Analysis of Gas Developed per Gramme with Different Sporting and Military Smokeless Powders Now In Use
______________________________________________________________________
| | | | |
Name of Explosive. | Calories | Permanent | Aqueous | Total Volume |
| per grm. | Gases. | Vapour. | of Gas at 0° |
| | | | and 760 mm. |
______________________|__________|___________|_________|______________|
| | cc/grm | cc/grm | cc/grm |
E.C. powder, English | 800 | 420 | 154 | 574 |
S.S. powder | 799 | 584 | 150 | 734 |
Troisdorf, German | 943 | 700 | 195 | 895 |
Rifleite, English | 864 | 766 | 159 | 925 |
B.N., French | 833 | 738 | 168 | 906 |
Cordite, English | 1253 | 647 | 235 | 882 |
Ballistite, German | 1291 | 591 | 231 | 822 |
Ballistite, Italian | 1317 | 58l | 245 | 826 |
and Spanish | | | | |
______________________|__________|___________|_________|______________|
The figures in column headed "Co-efficient of Potential Energy" serve as a measure of comparison of the power of the explosives, and are the products of the number of calories by the volume of gas, the last three figures being suppressed in order to simplify the results.
The amounts of water found were calculated for comparison as volumes of
H_{2}O gas at 0° and 760 mm.
E.C. powder consists principally of nitro-cellulose mixed with barium nitrate and a small proportion of camphor.
S.S. of nitro-lignine mixed with barium nitrate and nitro-benzene.
Troisdorf powder is gelatinised nitro-cellulose; rifleite gelatinised nitro-cellulose and nitro-benzene.
Cordite contains 58 per cent. nitro-glycerine, 37 per cent. gun-cotton, and 5 per cent. vaseline.
Ballistite (Italian) consists of equal parts nitro-cellulose and nitro- glycerine, and 1/2 per cent. of aniline. The German contains a higher percentage of nitro-cellulose.
TABLE SHOWING THE HEAT DEVELOPED BY EXPLOSIVES CONTAINING NITRO-GLYCERINE AND NITRO-CELLULOSE IN DIFFERENT PROPORTIONS.
______________________________________________________________________
Composition of Explosives. | Calories per cent.
_____________________________________________|________________________
Nitro-cellulose | |
(N = 13.3 per cent.). | Nitro-glycerine. |
| |
100 per cent. dry pulp | 0 | 1061
100 " gelatinised | 0 | 922
90 " | 10 per cent. | 1044
80 " | 20 " | 1159
70 " | 30 " | 1267
60 " | 40 " | 1347
50 " | 50 " | 1410
40 " | 60 " | 1467
0 " | 100 " | 1652
__________________________|__________________|________________________
| |
Nitro-cellulose | |
(N=12.24 per cent.) | Nitro-glycerine. |
| |
80 per cent. | 20 per cent. | 1062
60 " | 40 " | 1288
50 " | 50 " | 1349
40 " | 60 " | 1405
| |
__________________________|__________________|________________________|
Nitro-cellulose | |
(N = 13.3 per cent.). | Nitro-glycerine. | Vaseline.
| |
55 per cent. | 40 per cent. | 5 per cent. 1134
35 " | 60 " | 5 " 1280
__________________________|__________________|________________________
TABLE OF RESULTS OBTAINED BY LIEUT. W. WALKE., OF THE ARTILLERY, U.S.A, WITH QUINAN'S PRESSURE GAUGE.
Nitro-glycerine being taken as 100. (From U.S. Naval Inst. Jour.)
__________________________________________________________________________
| | |
| Compression | Order of |
Name of Explosive. | of Lead | Strength. |
| | |
| Inch. | |
Explosive gelatine | 0.585 | 106.17 |
Hellhoffite | 0.585 | 106.17 |
Nitro-glycerine | 0.551 | 100.00 | Standard, N.G.
Nobel's smokeless powder | 0.509 | 92.38 |
Nitro-glycerine | 0.509 | 92.37 |
Gun-cotton | 0.458 | 83.12 | U.S. naval torpedo
| | | gun-cotton
Gun-cotton | 0.458 | 83.12 | Stowmarket.
Nitro-glycerine | 0.451 | 81.85 | Vouges, N.G.
Gun-cotton | 0.448 | 81.31 |
Dynamite No. 1 | 0.448 | 81.31 |
Dynamite de Traul | 0.437 | 79.31 |
Emmensite | 0.429 | 77.86 |
Amide powder | 0.385 | 69.87 |
Oxonite | 0.383 | 69.51 |
Tonite | 0.376 | 68.24 | G.C. 52.5%, and
| | | Ba(NO_{3})_{2}, 47.5%
Bellite | 0.362 | 65.70 |
Rack-a-rock | 0.340 | 61.71 |
Atlas powder | 0.333 | 60.43 |
Ammonia dynamite | 0.332 | 60.25 |
Volney's powder No. 1 | 0.322 | 58.44 | Nitrated naphthalene.
" No. 2 | 0.294 | 53.18 | " "
Melinite | 0.280 | 50.82 | Picric acid 70%, and
| | | sol. nitro-cotton 30%.
Silver fulminate | 0.277 | 50.27 |
Mercury | 0.275 | 49.91 |
Mortar powder | 0.155 | 28.13 |
_________________________|_____________|___________|______________________
~Composition of some of the Explosives in Common Use.~
~Ordinary Dynamite.~
Nitro-Glycerine 75 per cent.
Kieselguhr 25 "
~Amvis.~
Nitrate of Ammonia 90 per cent.
Chloro-di-nitro Benzene 5 "
Wood Pulp 5 "
~Ammonia Nitrate Powder.~
Nitrate of Ammonia 80 per cent.
Chlorate of Potash 5 "
Nitro-Glucose 10 "
Coal Tar 5 "
~Celtite.~
Nitro-Glycerine 56-59 parts.
Nitro-Cotton 2-3.5 "
KNO_{3} 17-21 "
Wood Meal 8-9 "
Ammonium Oxalate 11-13 "
Moisture 0.5-1.5 "
~Atlas Powders.~
Sodium Nitrate 2.0 per cent.
Nitro-Glycerine 75.0 "
Wood Pulp 21.0 "
Magnesium Carbonate 2.0 "
~Dauline.~
Nitro-Glycerine 50 per cent.
Sawdust 30 "
Nitrate of Potash 20 "
~Vulcan Powder.~
Nitro-Glycerine 30 per cent.
Nitrate of Soda 52.5 "
Sulphur 7.0 "
Charcoal 10.5 "
~Vigorite.~
Nitro-Glycerine 30 per cent.
Nitrate of Soda 60 "
Charcoal 5 "
Sawdust 5 "
~Rendrock.~
Nitrate of Potash 40 per cent.
Nitro-Glycerine 40 "
Wood Pulp 13 "
Paraffin or Pitch 7 "
~Ammonia Nitrate Powder.~
Ammonia Nitrate 80 per cent.
Potassium Chlorate 5 "
Nitro-Glucose 10 "
Coal Tar 5 "
~Hercules Powders.~
Nitro-Glycerine 75 to 40 per cent.
Sugar 1 " 15.66 "
Chlorate of Potash 1.05 " 3.34 "
Nitrate of Potash 2.10 " 31.00 "
Carbonate of Magnesia 20.85 " 10.00 "
~Carbo-Dynamite.~
Nitro-Glycerine 90 per cent.
Charcoal 10 "
~Geloxite (Permitted List).~
Nitro-Glycerine 64-54 parts.
Nitro-Cotton 5-4 "
Nitrate of Potash 22-13 "
Ammonium Oxalate 15-12 "
Red Ochre 1-0 "
Wood Meal 7-4 "
The Wood Meal to contain not more than 15% and not less than 5% moisture.
~Giant Powder.~
Nitro-Glycerine 40 per cent.
Sodium Nitrate 40 "
Rosin 6 "
Sulphur 6 "
Guhr 8 "
~Dynamite de Trauzel.~
Nitro-Glycerine 75 parts.
Gun-Cotton 25 "
Charcoal 2 "
~Rhenish Dynamite.~
Solution of N.G. in Naphthalene 75 per cent.
Chalk, or Barium Sulphate 2 "
Kieselguhr 23 "
~Ammonia Dynamite.~
Ammonia Nitrate 75 parts.
Paraffin 4 "
Charcoal 3 "
Nitro-Glycerine 18 "
~Blasting Gelatine.~
Nitro-Glycerine 93 per cent.
Nitro-Cotton 3 to 7 "
~Gelatine Dynamite.~
Nitro-Glycerine 71 per cent.
Nitro-Cotton 6 "
Wood Pulp 5 "
Potassium Nitrate 18 "
~Gelignite.~
Nitro-Glycerine 60 to 61 per cent.
Nitro-Cotton 4 " 5 "
Wood Pulp 9 " 7 "
Potassium Nitrate 27 "
~Forcite.~
Nitro-Glycerine 49 per cent.
Nitro-Cotton 1.0 "
Sulphur 1.5 "
Tar 10.0 "
Sodium Nitrate 38.0 "
Wood Pulp 5 "
(The N.-G., &c., varies.)
~Tonite No. 1.~
Gun-Cotton 52-50 per cent.
Barium Nitrate 47-40 "
~Tonite No. 2.~
Contains Charcoal also.
~Tonite No. 3.~
Gun-Cotton 18 to 20 per cent.
Ba(NO_3)_2 70 " 67 "
Di-nitro-Benzol 11 " 13 "
Moisture 0.5 " 1 "
~Carbonite.~
Nitro-Glycerine 17.76 per cent.
Nitro-Benzene 1.70 "
Soda 0.42 "
KNO_3 34.22 "
Ba(NO_3)_2 9.71 "
Cellulose 1.55 "
Cane Sugar 34.27 "
Moisture 0.36 "
________
99.99
~Roburite.~
Ammonium Nitrate 86 per cent.
Chloro-di-nitro-Benzol 14 "
~Faversham Powder.~
Ammonium Nitrate 85 per cent.
Di-nitro-Benzol 10 "
Trench's Flame-extinguishing Compound 5 "
~Favierite No. 1.~
Ammonium Nitrate 88 per cent.
Di-nitro-Naphthalene 12 "
~Favierite No. 2.~
No. 1 Powder 90 per cent.
Ammon. Chloride 10 "
~Bellite.~
Ammonium Nitrate 5 parts.
Meta-di-nitro-Benzol 1 "
~Petrofacteur.~
Nitro-Benzene 10 per cent.
Chlorate of Potash 67 "
Nitrate of Potash 20 "
Sulphide of Antimony 3 "
~Securite.~
Mixtures of Meta-di-nitro-Benzol 26 per cent. and Nitrate of Ammonia 74 "
~Rack-a-Rock.~
Potassium Chlorate 79 parts.
Mono-nitro-Benzene 21 "
~Oxonite.~
Nitric Acid (sp. gr. 1.5) 54 parts.
Picric Acid 46 "
~Emmensite.~
Emmens Acid 5 parts.
Ammonium Nitrate 5 "
Picric Acid 6 "
~Brugère Powder.~
Ammonium Picrate 54 per cent.
Nitrate of Potash 46 "
~Designolle's Torpedo Powders.~
Potassium Picrate 55 to 50 per cent.
Nitrate of Potash 45 " 50 "
~Stowite.~
Nitro-Glycerine 58 to 61 parts.
Nitro-Cotton 4.5 " 5 "
Potassium Nitrate 18 " 20 "
Wood Meal 6 " 7 "
Oxalate of Ammonia 11 " 15 "
The Wood Meal shall contain not more than 15% and not less than 5% by weight of moisture. The explosive shall be used only when contained in a non-water-proofed wrapper of parchment—No. 6 detonator.
~Faversham Powder.~
Nitrate of Ammonium 93 to 87
Tri-nitro-Toluol 11 " 9
Moisture 1 " —
~Kynite.~
Nitro-Glycerine 24-26 parts.
Wood-Pulp 2.5-3.5 "
Starch 32.5-3.5 "
Barium Nitrate 31.5-34.5 "
CaCO_{3} 0-0.5 "
Moisture 3.0-6.0 "
Must be put up only in water-proof parchment paper, and No. 6 electric detonator used.
~Rexite.~
Nitro-Glycerine 6.5-8.5 parts.
Ammonium Nitrate 64-68 "
Sodium Nitrate 13-16 "
Tri-nitro-Tolulene 6.5-8.5 "
Wood Meal 3-5 "
Moisture .5-1.4 "
Must be contained in water-proof case (stout paper), water-proofed with
Resin and Cerasin—No. 6 detonator.
~Withnell Powder.~
Ammonium Nitrate 88-92 parts.
Tri-nitro-Toluene 4-6 "
Flour (dried at 100° C.) 4-6 "
Moisture 0-15 "
Only to be used when contained in a linen paper cartridge, water-proofed with Carnuba Wax, Parrafin—No. 7 detonator used.
~Phenix Powder.~
Nitro-Glycerine 28-31 parts.
Nitro-Cotton 0-1 "
Potassium Nitrate 30-34 "
Wood Meal 33-37 "
Moisture 2-6 "
~SMOKELESS POWDERS.~
~Cordite.~
Nitro-Glycerine 58 per cent. +or- .75
Nitro-Cotton 37 " +or- .65
Vaseline 5 " +or- .25
~Cordite, M.D.~
Nitro-Glycerine 30 per cent. +or- 1
Nitro-Cotton 65 " +or- 1
Vaseline 5 " +or- .25
Analysis of—
By W. Mancab and A.E. Leighton.
~E.C. Powder.~
Nitro-Cotton 79.0 per cent.
Potassium Nitrate 4.5 "
Barium Nitrate 7.5 "
Camphor 4.1 "
Wood Meal 3.8 "
Volatile Matter 1.1 "
~Walarode Powder.~
Nitro-Cotton 98.6 per cent.
Volatile Matter 1.4 "
~Kynoch's Smokeless.~
Nitro-Cotton 52.1 per cent.
Di-nitro-Toluene 19.5 "
Potassium Nitrate 1.4 "
Barium Nitrate 22.2 "
Wood Meal 2.7 "
Ash 0.9 "
Volatile Matter 1.2 "
~Schultze.~
Nitro-Lingin 62.1 per cent.
Potassium Nitrate 1.8 "
Barium Nitrate 26.1 "
Vaseline 4.9 "
Starch 3.5 "
Volatile Matter 1.0 "
~Imperial Schultze.~
Nitro-Lignin 80.1 per cent.
Barium Nitrate 10.2 "
Vaseline 7.9 "
Volatile Matter 1.8 "
~Cannonite.~
Nitro-Cotton 86.4 per cent.
Barium Nitrate 5.7 "
Vaseline 2.9 "
Lamp Black 1.3 "
Potassium Ferro-cyanide 2.4 "
Volatile Matter 1.3 "
~Amberite.~
Nitro-Cotton 71.0 per cent.
Potassium Nitrate 1.3 "
Barium Nitrate 18.6 "
Wood Meal 1.4 "
Vaseline 5.8 "
~Sporting Ballistite.~
Nitro-Glycerine 37.6 per cent
Nitro-Cotton 62.3 "
Volatile Matter 0.1 "
The following is a complete List of the Permitted Explosives as Defined in the Schedules to the Explosives in Coal Mines Orders of the 20th December 1902, of the 24th December 1903, of the 5th September 1903, and 10th December 1903:—
Albionite.
Ammonal.
Ammonite.
Amvis.
Aphosite.
Arkite.
Bellite No. 1.
Bellite No. 2.
Bobbinite.
Britonite.
Cambrite.
Carbonite.
Clydite.
Coronite.
Dahmenite A.
Dragonite.
Electronite.
Faversham Powder.
Fracturite.
Geloxite.
Haylite No. 1.
Kynite.
Negro Powder.
Nobel's Ardeer Powder.
Nobel Carbonite.
Normanite.
Pit-ite.
Roburite No. 3.
Saxonite.
Stow-ite.
Thunderite.
Victorite.
Virite.
West Falite No. 1.
West Falite No. 2.
INDEX.
Abel's, Sir Frederick, method of manufacturing gun-cotton, 57.
Abel's heat test, 249.
Acid mixture for nitrating nitro-glycerine, 23.
Air pressure in nitrator, 28.
Alkalinity in nitro-cellulose, 217.
Amberite, 189.
Ammonite, 149.
Analyses of collodion-cotton, 81. gelatine dynamites, 123.
Analysis of explosives, 197. acetone, 209. blasting gelatine, 199. cap composition, 241. cordite, 206. celluloid, 230. dynamite, 197. forcite, 202. fulminate, 240. glycerine, 233. gun-cotton, 212. nitric acid, 24. picric acid, 230. tonite, 205. waste acids, 239.
Armstrong on the constitution of the fulminates, 159.
Atlas powder, 119.
Auld on acetone, 211.
Axite, 176.
Ballistite, 179.
Beater or Hollander for pulping gun-cotton, 64.
Bedson, Prof., on roburite explosion gases, 140.
Bellite, 142.
Benzene, explosives derived from, 132.
Benzene, mono-nitro- and di-nitro-benzene, 134.
Bergmann and Junk on nitro-cellulose tests, 268.
Bernthsen summary of nitro-benzenes, 133.
Blasting gelatine, 119.
Blasting charge, preparation of, 166.
B.N. powder, 190.
Boiling-point of N.G., 19.
Boutnny's nitro-glycerine process, 15.
Brown on wet gun-cotton, 56.
Brugère's powder, 195.
Bucknill's resistance coil, 13.
Calculation of volume of gas evolved in an explosive reaction, 276.
Cannonite, 189.
Cellulose, 2, 47.
Celluloid manufacture, 91. analysis, 230. cartridges, 91. uses of, 90. Field's papers on, 93. fibre for, 94. nitration of fibre, &c., 95. formula of, 57.
Champion and Pellet's method of determining nitrogen, 223.
Chenel's modification of Kjeldahl's method, 227.
Collodion-cotton, 79.
Comparative tests of black and nitro-powders, 193.
Compressing gun-cotton, 77.
Composition of waste acids from nitro-glycerine, 43.
Composition of some common explosives, 290.
Conduits for nitro-glycerine, 7.
Cooppal powder, 5, 189.
Cordite manufacture, 169. analysis, 206.
Cresilite, 158.
Cross and Bevan on nitro-jute, 107.
Crusher gauge, 284.
Cundill, Colonel, classification of dynamites, 112.
Danger area, 5.
Dangers in the manufacture of gun-cotton, 85.
Decomposition of cellulose, 54.
Definition of explosives in Order of Council (Explosives Act), 1.
Determination of N_{2}O_{4} in nitric acid, 24.
Determination of strength of H_{2}SO_{4}, 25.
Determination of relative strength of explosives, 272.
Detonators, 163.
Di-nitro-toluene, 138.
Dipping cotton in manufacture of gun-cotton, 60.
Divers and Kawakita on the fulminates, 159.
Dixon, Prof. H.B., on roburite explosions, 139.
Drying house for gun-cotton, 122.
Dynamite, efficiency of, 118. frozen dynamite, 116. gelatine dynamite, 119. properties of kieselguhr dynamite, 116. Reid & Borland's carbo-dynamite, 119. Rhenish dynamite, 119. various kinds of, 119.
E.C. powder, 186.
Electronite, 151.
Emmensite, 195.
Equation of formation of nitro-glycerine, 16.
Equation of formation of nitro-cellulose, 50.
Exploders, electric, 167.
Explosion gases of dynamite, 19. nitro-glycerine, 18. gun-cotton, 55. roburite, 139.
Exudation test gelatines, 257.
Faversham powder, 147.
Favier's explosive, 149.
Field on celluloid, 93, 99.
Firing-point of explosives, 247.
Filite, 180.
Filtering nitre-glycerine, 37.
Flameless explosives, 89, 138, 144.
Formation of white matter in the nitration of N.G., 39.
Forcite, 119.
France, 82.
Free fatty acid in glycerine, 39, 235.
Freeing nitric acid from N_{2}O_{4}, 25.
Freezing-point of N.G., 21.
French Commission on Ammonium Nitrate, 142.
Fulminates constitution, 159.
Fulminate of mercury, 159, 240.
Fulminate of silver, 161.
Fuses, various kinds of, 166.
Gases formed by the decomposition of nitro-glycerine, 18.
Gelatine explosives, analysis of, 199.
Glycerine, analysis of, 233. formula of, 16. nitration of, 23.
Greiner's powder, 190.
Gun-cotton, analysis of, 212. boiling, 64. complete series of, 52, 54. compressing, moulding, and packing, 67, 77, 78. dipping and steeping the cotton, 60. drying the cotton, 58. granulation of, 79. manufacture of, 57. Abel's method, 57. Stowmarket, 57. Waltham Abbey, 71. products of decomposition of, 55. properties of, 54. pulping, 65. washing, 63. as a mining explosive, 56.
Guttmann's nitric acid plant, 45.
Guttmann's heat test, 256.
Handy's method for determining moisture in dynamite, 197.
Hannah, Dr N., on roburite explosion gases, 139.