[Footnote A:  Roux and Sarran.]

CHAPTER V.

NITRO-BENZOL, ROBURITE, BELLITE, PICRIC ACID, &c.

Explosives derived from Benzene—­Toluene and Nitro-Benzene—­Di- and
Tri-nitro-Benzene—­Roburite:  Properties and Manufacture—­Bellite: 
Properties, &c.—­Securite—­Tonite No. 3.—­Nitro-Toluene—­
Nitro-Naphthalene—­Ammonite—­Sprengel’s Explosives—­Picric Acid—­
Picrates—­Picric Powders—­Melinite—­Abel’s Mixture—­Brugere’s Powders—­
The Fulminates—­Composition, Formula, Preparation, Danger of, &c.—­
Detonators:  Sizes, Composition, Manufacture—­Fuses, &c.

The Explosives derived from Benzene.—­There is a large class of explosives made from the nitrated hydro-carbons—­benzene, C_{6}H_{6}; toluene, C_{7}H_{8}; naphthalene, C_{10}H_{8}; and also from phenol (or carbolic acid), C_{6}H_{5}OH.  The benzene hydro-carbons are generally colourless liquids, insoluble in water, but soluble in alcohol and ether.  They generally distil without decomposition.  They burn with a smoky flame, and have an ethereal odour.  They are easily nitrated and sulphurated; mono, di, and tri derivatives are readily prepared, according to the strength of the acids used.  It is only the H-atoms of the benzene nucleus which enter into reaction.

Benzene was discovered by Faraday in 1825, and detected in coal-tar by Hofmann in 1845.  It can be obtained from that portion of coal-tar which boils at 80 deg. to 85 deg. by fractionating or freezing.[A] The ordinary benzene of commerce contains thiophene (C_{4}H_{4}S), from which it may be freed by shaking with sulphuric acid.  Its boiling point is 79 deg.  C.; specific gravity at 0 deg. equals 0.9.  It burns with a luminous smoky flame, and is a good solvent for fats, resins, sulphur, phosphorus, &c.  Toluene was discovered in 1837, and is prepared from coal-tar.  It boils at 110 deg.  C., and is still liquid at 28 deg.  C.

[Footnote A:  It may be prepared chemically pure by distilling a mixture of benzoic acid and lime.]

The mono-, chloro-, bromo-, and iodo-benzenes are colourless liquids of peculiar odour.  Di-chloro-, di-bromo-benzenes, tri- and hexa-chloro- and bromo-benzenes, are also known; and mono-chloro-, C_{6}H_{4}Cl(CH_{3}), and bromo-toluenes, together with di derivatives in the ortho, meta, and para modifications.  The nitro-benzenes and toluenes are used as explosives.  The following summary is taken from Dr A. Bernthsen’s “Organic Chemistry":—­