Part 13 (2/2)

The manner in which picric acid will decompose is thus dependent upon the initial te material absorb heat as fast as it is produced by the decoration If, however, the absorption is not sufficient to prevent deflagration, thisration will then end in explosion Thus, if an explosion were started in an isolated spot, it would extend throughout the eneral explosion

In the manufacture of picric acid the first obvious and most necessary precaution is to isolate the substance froht accidentally come into contact If pure er The finished material, however, must be carefully kept from contact with nitrates, chlorates, or oxides If only a little bit of lime or plaster becoerous A local explosionthe explosion of the whole rain fulminate, and M Turpin patented the use of picric acid, unmixed with any other substance, in 1885 The detonation of a small quantity of dry picric acid is sufficient to detonate aas much as 17 per cent of water

It is chiefly due to French cheel) that picric acid has come to the front as an explosive Melinite,[A] a substance used by the French Govern shells, was due to M Turpin, and is supposed to be little else than fused picric acid un-cotton dissolved in some solvent (acetone or ether-alcohol) Sir FA Abel has also proposed to use picric acid, mixed with nitrate of potash (3 parts) and picrate of a for shells This substance requires a violent blow and strong confinement to explode it I am not aware, however, that it has ever been officially adopted in this country

Messrs Designolles and Brugere have introducedof mixtures of potassiunolles introduced three kinds of picrate powders, composed as follows:--

___________________________________________________________________ | | | | | | | For Torpedoes | For Guns | For Small | | | and Shells | Ordinary Heavy | Arms | |___________________|_______________|___________________|___________| | | | | | | | Picrate of Potash | 55-50 | 164- 96 | 9 | 286-229 | | Saltpetre | 45-50 | 744-797 | 80 | 650-694 | | Charcoal || 92-107 | 11 | 64- 77 | |___________________|_______________|___________|_______|___________|

They were unpowder, 6 to 14 per cent of es claireater ballistic or disruptive effect, comparative absence of suns, owing to the absence of sulphur Brugere's powder is co 54 per cent

picrate of ammonia and 46 per cent potassic nitrate It is stable, safe to ood results in the Chassepot rifle, very little smoke, and its residue is small, and consists of carbonate of potash It is stated that 26 grrunpowder

[Footnote A: The British Lydite and the japanese shi+mose are said to be identical with Melinite]

Turpin has patented various um-arabic, oils, fats, collodion jelly, &c When the last-named substance is diluted in the proportion of from 3 to 5 per cent in a mixture of ether and alcohol, he states that the blocks of picric acid moulded with it will explode in a closed charammes of fulminate He also casts picric acid into projectiles, the cast acid having a density of about 16 In this state it resists the shock produced by the firing of a cannon, when contained in a projectile, having an initial velocity of 600way:--The acid is fused in a vessel provided with a false bottom, heated to 130 to 145 C by a current of steam under pressure, or simply by the circulation under the false bottolycerine, &c, heated to the same temperature Theto that of the blocks required, or it may be run into projectiles, which should be heated to a temperature of about 100 C, in order to prevent too rapid solidification

When cresylic acid (or cresol, C_{6}H_{4}(CH_{3})OH) is acted upon by nitric acid it produces a series of nitro compounds very similar to those formed by nitric acids on phenol, such as sodium di-nitro-cresylate, known in the arts as victoria yellow Naphthol, a phenol-like body obtained from naphthalene, under the same conditions, produces sodium di-nitro- naphthalic acid, C_{10}H_{6}(NO_{2})_{2}O The explosive known as ”roburite” contains chloro-nitro-naphthalene, and romit, a Swedish explosive, nitro-naphthalene

~Tri-nitro-cresol~, C_{7}H_{4}(NO_{2})_{3}OH--A body very similar to tri- nitro-phenol, crystallises in yellow needles, slightly soluble in cold water, ratherwater, alcohol, and ether It melts at about 100 C In France it is known as ”Cresilite,” andshells By neutralising a boiling saturated solution of tri-nitro-cresol with ammonia, a double salt of a, which is similar to ammonium picrate This salt is known as ”Ecrasite,” and has been used in Austria for charging shells It is a bright yellow solid, greasy to the touch, nites when brought into contact with an incandescent body or open flaly confined, and is insensitive to friction or concussion It is claith of dynar the excellent properties attributed to this explosive, Lieut W Walke (”Lectures on Explosives,”

p 181) says, ”Several imperfectly explained and unexpected explosions have occurred in loading shells with this substance, and have prevented its general adoption up to the present time”

~The Fulminates~--The fulminates are salts of fulminic acid, C_{2}N_{2}O_{2}H_{2} Their constitution is not very well understood Dr E Divers, FRS, and Mr Kawakita (_Cheive the forOC = N / | | Hg | O and | O | / | / -C = N AgC = N

whereas Dr HE Ar, FRS, would prefer to write the formula of fulminic acid

ONCOH

| C(NOH),

and AF Hollens to| | C:NO,

and R Schol (_Ber_, v xxiii, p 3505),

C:NO || Hg

C:NO

They are very generally regarded as iso-nitroso compounds

The principal compound of fulalcohol to the solution, 1 part of ravity 136, and 5-1/2 parts of 90 per cent alcohol being used As soon as the mixture is in violent reaction, 6 parts more of alcohol are added slowly to moderate the action At first the mixture blackens from the separation of mercury, but this soon vanishes, and is succeeded by crystalline flocks of mercury ful the reaction, large quantities of volatile oxidation products of alcohol, such as aldehyde, ethylic nitrate, &c, are evolved frolycollic acid, remain in solution The mercury fulminate is then crystallised from hot water It forms white silky, delicate needles, which are with difficulty soluble in cold water In the dry state it is extre, or by friction or percussion, as also on contact with concentrated sulphuric acid The reaction that takes place upon its deco + 2CO + N_{2} (284)

According to this equation 1 grm of the fulrms) Berthelot and Vicille have obtained a yield of 2342 cc, equal to 667 litres for one equivalent 284 grms

Dry fulminate explodes violently when struck, compressed, or touched with sulphuric acid, or as an incandescent body If heated slowly, it explodes at 152 C, or if heated rapidly, at 187 C It is often used mixed with potassium chlorate in detonators The reaction which takes place in this case is 3C_{2}N_{2}O_{2}Hg + 2KClO_{3} = 3Hg + 6CO_{2} + 3N_{2} + 2KCl

On adding copper or zinc to a hot saturated solution of the salt, fulhly explosive green crystals There is also a double fulminate of copper of ammonia, and of copper and potassiu_{2}, is prepared in a similar manner to the mercury salt It separates in fine white needles, which dissolve in 36 parts of boiling water, and are with difficulty soluble in cold water At above 100 C, or on the weakest blow, it explodes with fearful violence Even when covered ater it is more sensitive than the mercury salt It forms a very sensitive double salt with ammonia and several other metals