EXPLOSIVES. 376 EXPLOSIVES. are typical of only one variety: Alias powder, consisting of nitroglycerin 75 parts, wood-fibre 21 parts, sodium nitrate 2 parts, magnesium carbonate 2 parts; carbonite, consisting of wood- meal 40 1 2 parts, sodium nitrate 34 pails, nitro- glycerin 25 parts, and sodium carbonate one- half part: dunlin, consisting of nitroglycerin 40 parts, sawdust 30 parts, potassium nitrate 20 parts; giant powder, consisting of nitroglycerin 40 parts, sodium nitrate -41 > parts, powdered resin 8 parts, kieselguhr 8 parts, sulphur ti parts; Hercules poioder, consisting of sodium nitrate 45 parts, nitroglycerin 40 parts, wood-pulp 11 parts, sodium chloride 1 part, and magnesium carbonate 1 part; Judson poioder, consisting of sodium nitrate 64 parts, sulphur 16 parts, cannel coal 15 parts, nitroglycerin 5 parts; lithofrac- 1 1 in; consisting of nitroglycerin 54 % parts, kieselguhr 16% parts, barium nitrate 14% parts, sulphur 7 parts, manganese 2 parts, soda 2 parts, wood-meal 2 parts, bran 1 part; meganite, con- sisting of nitroglycerin 60 parts, sodium nitrate 20 parts, nitrated vegetable ivory 10 parts, ni- trated wood 10 parts: rheatite, consisting of nitroglycerin 04 parts, sodium nitrate 18 parts, decayed wood 11 parts, wood-meal 7 part-: safety nitro-powder, consisting of nitroglycerin 68.81 parts, sodium nitrate 18.35 parts, wood- pulp 12.84 parts: stonite, consisting of nitro- glycerin 68 parts, kieselguhr 20 part-, potassium nitrate 8 parts, and wood-meal 4 parts; oigorite, consisting of potassium chlorate 49 parts, nitro- glycerin 68 parts, kieselguhr 20 parts, potassium nitrate 7 parts, magnesium carbonate, moisture, etc., 5 parts; and Vulcan poioder, consisting of sodium nitrate 52.5 parts, nitroglycerin 30 parts, charcoal 10.5 parts, and sulphur 7 parts. Sprengel Explosives or Pakclastites. In 1873 Dr. Hermann Sprengel described a class of explosives consisting of two inexplosive ingredi- ents, which, when mixed together, yielded a com- pound capable of violent detonation. The safety with which such explosives could be transported to the place of action led to their study by the experts on explosives of various governments, and a number of valuable preparations of this class have since been patented in different countries. A number of these have already been described, as rackarock, under Explosive Mixtures of the Chlorates, and ammonites, bellite, roburite, ro- mite, and securite under Explosive Compounds l)e- ric.l by Nitro Substitution, in addition to these there should be mentioned hellhoffite, consisting of nitric acid with a specific gravity of 1.5, 53 parts, and meta-di-nitrobenzine 17 pari-: and panclastite, consisting of nitro tetroxide combined ome combustible substance, such as a hydro- carbon, vegetable", animal, and mineral oils, fats, and their derivatives, but preferably with carbon disulphide. In this class maj be included the picric acid compounds, which consist of tri nitro- phenol or picric acid brought into a dense state by fusion, anil used as a filler for shells. This ilosive, differing only in the details of its manufacture, which arc kepi secrel by the re pectivi ■■■ yernments, i- called lyddite in Eng- land and el '•>!• in France. The ecrasiti of the mi is made by substituting tri- nitroeresol for tri nitrophenol (picric acid) . Fulminates and imi s. The fad i ha1 cer tain nitrates, when heated with alcohol and an i nitric acid, yield peculiar crystalline, i ing precipitati -. has been know n for more than a century, and this property has been taken advantage of in the preparation of ex- plosives. The best-known member of this el is the mercury fulminate, which is made by dis- solving mercury in nitric acid, to which solution when cool alcohol is added. The gray explosive mercury fulminate is thrown down by the a. Mi tion of water. The precipitate is then carefully washed and air-dried. It is exceedingly sensitive to heat and shock of any kind, and may be det- onated by heat at a temperature variously given from 149° C. to 200° C. The silver fulminate, which is formed by heating an aqueous solution of silver nitrate with strong nitric acid and al- cohol, is of similar nature. Mercury fulminate finds an extensive application in detonators for guncotton and for nitroglycerin compounds; also for cap and detonating compositions. The amides, such as nitrogen chloride and nitrogen iodide, have been referred to under Theory of Explosives, and have no economic interest. Military Uses of Explosives. The principal use of explosives is, of course, for military pur- poses, where they are employed as propelling and as bursting charges for projectiles. An explosive for use as a propelling charge in a gun should give in that gun as low maximum pressures and as high projectile velocity as possible. The older powders were finely pulverized. About 1860 and later, it was customary to press the powder after mixing into a cake, afterwards broken be- tween rollers into irregular grains which were sorted by screens into different sizes, musket, mortar, cannon, and mammoth; the latter from 0.6 inch to 0.9 inch. At this date. 1800, Gen- eral Rodman proposed cylindrical cakes, nearly the diameter of the bore and 3 inches lone. pierced by 14-inch holes % inch apart, reason ing that the burning on the inner surfaces of these holes would give a constantly increasing surface, and therefore an increasing rate of generation of gas, a condition which he recog- nized to be desirable. At the time this form was not deemed preferable to the mammoth, and his principle was adopted only after a number of years, and was preceded by the use of other powders — as the sphero-hexagonal — molded sim- ply for uniformity of size. His grain when adopted was modified to a hexagonal prism about. 1 inch long and wide, pierced by one or several holes. A It BLACK POWDER. A — Sphero-hexagonal grain, B— Hexagonal grain. About 1882 the Germans introduced 'In-own' a' powder in the same form grains, hut u-iiiL' charcoal no1 so much baked, and therefore giving a slower powder. A 'slow bin nine' B powder soon came forward as an improvement I on- continued efforts were made to gel a powder of more power per unit of volume, which would give in the reduced calibre small arm a higher velocitj than gunpowder, with permissible prea -nil-. The high explosives were tried, especially
