A.—Explosive Mixtures.

Gunpowder.—This explosive mixture is composed of seventy-five parts of nitre (saltpetre), fifteen parts of charcoal, and ten parts of sulphur.

On being ignited, the oxygen which is feebly held by the nitrogen combines with the carbon, forming carbonic oxide gas, whilst the sulphur unites with the potassium of the nitre, the whole combination being accompanied by a great evolution of heat and expansion of gas, and the nitrogen is set free.

Properties, &c.—A spark, friction between hard bodies, or a temperature of 572° F., are any of them sufficient to cause an explosion of gunpowder.

Slight moisture, due to damp air, &c., produces caking and deterioration.

Wetting causes permanent destruction.

Frost does not injure it.

It can be fired by ordinary methods.

It can be transported and handled with safety and great ease.