_______________________________________________________

____________
|                   |               |                   |           |
|                   | For Torpedoes |      For Guns.    | For Small |
|                   | and Shells.   | Ordinary.   Heavy. |   Arms.   |
|___________________|_______________|___________________|___

________|
|                   |               |           |       |           |
| Picrate of Potash | 55-50         | 16.4- 9.6 |  9    | 28.6-22.9 |
| Saltpetre         | 45-50         | 74.4-79.7 | 80    | 65.0-69.4 |
| Charcoal          | ...           |  9.2-10.7 | 11    |  6.4- 7.7 |
|___________________|_______________|___________|_______|___

________|

They were made much like ordinary gunpowder, 6 to 14 per cent. of moisture being added when being milled.  The advantages claimed over gunpowder are greater strength, and consequently greater ballistic or disruptive effect, comparative absence of smoke, and freedom from injurious action on the bores of guns, owing to the absence of sulphur.  Brugere’s powder is composed of ammonium picrate and nitre, the proportions being 54 per cent. picrate of ammonia and 46 per cent. potassic nitrate.  It is stable, safe to manufacture and handle, but expensive.  It gives good results in the Chassepot rifle, very little smoke, and its residue is small, and consists of carbonate of potash.  It is stated that 2.6 grms. used in a rifle gave an effect equal to 5.5 grms. of ordinary gunpowder.

[Footnote A:  The British Lydite and the Japanese Shimose are said to be identical with Melinite.]

Turpin has patented various mixtures of picric acid, with gum-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 chamber with a priming of from 1 to 3 grammes of fulminate.  He also casts picric acid into projectiles, the cast acid having a density of about 1.6.  In this state it resists the shock produced by the firing of a cannon, when contained in a projectile, having an initial velocity of 600 metres.  It is made in the following way:—­The acid is fused in a vessel provided with a false bottom, heated to 130 deg. to 145 deg.  C. by a current of steam under pressure, or simply by the circulation under the false bottom of a liquid, such as oil, chloride of zinc, glycerine, &c., heated to the same temperature.  The melted picric acid is run into moulds of a form corresponding to that of the blocks required, or it may be run into projectiles, which should be heated to a temperature of about 100 deg.  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.