Nitro-mannite is more dangerous than nitro-glycerine, as it is more sensitive to shock. It is intermediate in its shattering properties between nitro-glycerine and fulminate of mercury. It explodes by the shock of copper on iron or copper, and even of porcelain on porcelain, provided the latter shock be violent. Its heat of formation from its elements is +156.1 calories. It is not manufactured upon the commercial scale. Besides the nitro compounds already described, there are many others, but they are of little importance, and are none of them made upon the large scale. Among such substances are _nitro-coal_, which is made by the action of nitric acid on coal; _nitro-colle_, a product which results from the action of nitric acid on isinglass or gelatine, soaked in water. It is then treated with the usual acids. Another method is to place strong glue in cold water until it has absorbed the maximum amount of the latter. The mixture is solidified by the addition of nitric acid, nitrated in the usual way, and well washed. Abel's _Glyoxiline_ is only nitrated gun-cotton impregnated with nitro- glycerine. Nitro-lignine is only nitro-cellulose made from wood instead of cotton; and nitro-straw is also only nitro-cellulose. The explosive known as _Keil's Explosive_ contains nitro-glucose. Nitro-molasses, which is a liquid product, has also been proposed, and nitro-saccharose, the product obtained by the nitration of sugar. It is a white, sandy, explosive substance, soluble in alcohol and ether. When made from cane sugar, it does not crystallise; but if made from milk sugar, it does. It has been used in percussion caps, being stronger and quicker than nitro-glycerine. It is, however, very sensitive and very hygroscopic, and very prone to decomposition. Nitro-tar, made from crude tar-oil, by nitration with nitric acid of a specific gravity of 1.53 to 1.54. Nitro-toluol is used, mixed with nitro-glycerine. This list, however, does not exhaust the various substances that have been nitrated and proposed as explosives. Even such unlikely substances as horse dung have been experimented with. None of them are very much used, and very few of them are made upon the manufacturing scale. CHAPTER IV. _DYNAMITE AND GELATINES._ Kieselguhr Dynamite--Classification of Dynamites--Properties and Efficiency of Ordinary Dynamite--Other Forms of Dynamite--Gelatine and Gelatine Dynamites, Suitable Gun-Cotton for, and Treatment of--Other Materials used--Composition of Gelignite--Blasting Gelatine--Gelatine Dynamite--Absorbing Materials--Wood Pulp--Potassium Nitrate, &c.-- Manufacture and Apparatus used, and Properties of Gelatine Dynamites-- Cordite--Composition and Manufacture.