Part 13 (1/2)

The aes by h a brass tube, pushi+ng off the cartridges as the explosive is fed into theht back pressure; a cover is screwed on, and they then go to the dipping room, where they are dipped in hot wax to seal the ends; they are then packed in boxes of 5 lbs each and are ready for delivery The di-nitro-naphthalene is made at the factory Mono-nitro-naphthalene is first round to a fine powder, and further ground with the addition of 15 parts of refined naphthalene until thoroughly incorporated; it is then placed in an earthenware pan, and 30 parts of sulphuric acid of 66 B added, 2 parts at a ti H_{2}SO_{4} depends on the condition of the charge, and keeping it in a fluid state), with frequent agitation, day and night, during the first three or four days, afterwards three or four times a day In all fourteen days are occupied in the nitration process It is then strained through an earthenware strainer, washed ater, drained, and dried For the purpose of producing this ranulated condition, which is found , and further nitrification, it is placed in a tub, and live stea point (the tub should be about half full), cold water is then run in whilst violently agitating the contents until the naphthalene solidifies; it can then be easily drained and dried For the further treatment to make di-nitro-naphthalene, 18 parts of nitro-naphthalene are placed in an earthenware pan, together with 39 parts of sulphuric acid of 66 B, then 15 parts of nitric acid of 40 B are added, in s theof nitric acid is controlled by the fu, which should be kept down as much as possible The operation takes ten to twelve days, when 100 tirammes, are taken At the end of the nitration the di-nitro-naphthalene is removed to earthenware strainers, allowed to drain, washed with hot water and soda until all acid is removed, washed ater and dried The di-nitro- naphthalene gives so, as some acid is held in the crystals which is liable to round and washed with carbonate of soda before drying; an excess of carbonate of soda should not, however, be used

~Electronite~--This is a high explosive designed to afford safety in coal getting This iredients, and so proportioning theree of heat insufficient under the conditions of a ”blown-out” shot, to ignite fire damp or coal dust It is of the nitrate of ammonium class of permitted explosives It contains about 75 per cent of nitrate of ammonium, with the addition of nitrate of bariu froen, and a little carbon dioxide It is granulated with the object of preventing , to which nitrate of ammonium explosives are somewhat susceptible This explosive underwent soan in 1895, when 8 oz or 12 oz charges were fired unsteas, without any ignition taking place It is manufactured by Messrs Curtis's & Harvey Ltd at their factory, Tonbridge, Kent

~Sprengel's Explosives~--This is a large class of explosives The essential principle of theent at the ti required for use, the constituents of thevery often non-explosive bodies

This type of explosive is due to the late Dr Her up the idea that an explosion is a sudden co and coents to the violent shock of a detonator of fulminate These mixtures were made in such proportions that the mutual oxidation or de-oxidation should be theoretically co:--

1 One chemical equivalent of nitro-benzene to equivalents of nitric acid

2 Five equivalents of picric acid to 13 equivalents of nitric acid

3 Eighty-seven equivalents of nitro-naphthalene to 413 equivalents of nitric acid

4 Porous cakes, or lumps of chlorate of potash, exploded violently with bisulphide of carbon, nitro-benzol, carbonic acid, sulphur, benzene, and mixtures of these substances

No 1 covers the explosive known as _hellhoffite_, and No 2 is really oxonite, and No 4 resembles rack-a-rock, an explosive invented by Mr SR

Divine, and consisting of a mixture of chlorate of potash and nitro- benzol Roburite, bellite, and securite should perhaps be regarded as belonging to the Sprengel class of explosives, otherwise this class is not land The principalof a mixture of nitro-petroleum or nitro-tar oils and nitric acid, or ofof picric and nitric acids; and _Panclastite_, a naiven to various mixtures, proposed by M Turpin, such as liquid nitric peroxide, with bisulphide of carbon, benzol, petroleum, ether, or mineral oils

~Picric Acid, Tri-nitro-Phenol, or Carbazotic Acid~--Picric acid, or a tri-nitro-phenol (C_{6}H_{2}(NO_{2})_{3}OH)[2:4:6], is produced by the action of nitric acid on o, wool, aniline, resins, &c At one tium from Botany Bay (_Xanthorrhoea hastilis_) was chiefly used One part of phenol (carbolic acid), C_{6}H_{5}OH, is added to 3 parts of strong fuhtly warmed, and when the violence of the reaction has subsided, boiled till nitrous fuer evolved The resinouspicric acid is converted into a sodium salt by a solution of sodium carbonate, which thron sodium picrate in crystals

Phenol-sulphuric acid is noever,it closely rese nitro-benzol It is alsoit with strong sulphuric acid, then diluting the ”sulpho- carbolic”[A] acid ater, and afterwards running it slowly into a stone tank containing nitric acid This is allowed to cool, where the crude picric acid crystallises out, and the acid liquid (which contains practically no picric acid, but only sulphuric acid, with so poured down the drains The crude picric acid is then dissolved in water by the aid of steam, and allowed to cool when most of the picric acid recrystallises The mother liquor is transferred to a tank and treated with sulphuric acid, when a further crop of picric acid crystals is obtained The crystals of picric acid are further purified by recrystallisation, drained, and dried at 100 F on glazed earthenware trays by the aid of steam It can also be obtained by the action of nitric acid on ortho-nitro-phenol, para-nitro-phenol, and di-nitro-phenol (2:4 and 2:6), but not from meta-nitro-phenol, a fact which indicates its constitution[B]

[Footnote A: O and p phenolsulphonic acids

C_{3}H_{4}(OH)SO_{3}H + 3HNO_{3} = C_{6}H_{2}(NO_{2})_{3}OH + H_{2}SO_{4} + 2H_{2}O (Picric acid)]

[Footnote B: Carey Lea, _Amer Jour Sci_, (ii), xxxii 180]

Picric acid crystallises in yellow shi+ning pris an intensely bitter taste, and is poisonous It melts at 1225 C, sublily in cold water, more easily in hot water, still more in alcohol It stains the skin an intense yellow colour, and is used as a dye for wool and silk It is a strong acid, for well crystallised yellow salts, which detonate violently when heated, some of them also by percussion The potassiu needles very slightly soluble in water The sodium, ammonium, and barium salts are, however, easily soluble in water Picric acid, when heated, burns with a lue quantity without explosion; but the mere contact of certain metallic oxides, with picric acid, in the presence of heat, develops powerful explosives, which are capable of acting as detonators to an indefinite amount of the acid, wet or dry, which is within reach of their detonative influence The formula of picric acid is

C_{6}H_{2}|(NO_{2})_{3} |OH

which shows its for displaced by the NO_{2} group The equation of its formation from phenol is as follows:--

C_{6}H_{5}OH + 3HNO_{3} = C_{6}H_{2}(NO_{2})_{3}OH + 3H_{2}O

According to Berthelot, its heat of formation from its elements equals 491 calories, and its heat of total coen is equal to +6184 cals It hardly contains en necessary for its complete combustion

2C_{6}H_{2}(NO_{2})_{3}OH + O_{10} = 12CO_{2} + 3H_{2} + 3N_{2}

The percentage coen, 4922; hydrogen, 100; and carbon, 3144, equal to 6026 per cent of NO_{2} The products of decoen, and nitrogen, and the heat liberated, according to Berthelot, would be 1306 cals, or 570 cals per kilograases would be 190 litres per equivalent, or 829 litres per kilogramme To obtain a total combustion of picric acid it is necessary to ent, such as a nitrate, chlorate, &c It has been proposed to mix picric acid (10 parts) with sodium nitrate (10 parts) and potassium bi+chromate (83 parts) These proportions would furnish a third of oxygen in excess of the necessary proportion

Picric acid was not considered to be an explosive, properly so called, for a long time after its discovery, but the disastrous accident which occurred at Manchester (_vide_ Gov Rep No LxxxI, by Colonel (now Sir VD) Majendie, CB), and some experiments made by Dr Dupre and Colonel Majendie to ascertain the cause of the accident, conclusively proved that this vierong The experiments of Berthelot (_Bull de la Soc Chim

de Paris_, xlix, p 456) on the explosive deco of attention in this connection If a small quantity of picric acid be heated in a moderate fire, in a crucible, or even in an open test tube, it will ive off vapours which catch fire upon contact with air, and burn with a sooty fla liquid be poured out upon a cold slab, it will soon go out A small quantity carefully heated in a tube, closed at one end, can even be completely volatilised without apparent decomposition It is thus obvious that picric acid is lycerol and nitro-cellulose, and very considerably less explosive than the nitrogen compounds and fulminates

It would, however, be quite erroneous to assume that picric acid cannot explode when simply heated On the contrary, Berthelot has proved that this is not the case If a glass tube be heated to redness, and a minute quantity of picric acid crystals be then thrown in, it will explode with a curious characteristic noise If the quantity be increased so that the temperature of the tube is materially reduced, no explosion will take place at once, but the substance will volatilise and then explode, though with much less violence than before, in the upper part of the tube

Finally, if the amount of picric acid be still further increased under these conditions, it will undergo partial decorate Nitro-benzene, di-nitrobenzene, and mono-, di-, and tri-nitro-naphthalenes behave similarly