Schults's Powder.—In Schultz's powder, the cellulose is obtained from wood. The wood ie first sawn into sheets, about s in. thick, and then passed through a machine, which punches it up into grains of a uniform size. These are deprived of their resinous matter by a process of boiling in carbonate of soda, and are further cleansed by washing in water, steaming, and bleaching by chloride of lime. The grains, which are then pure cellulose, are converted into nitro-cellulose in the very same way as cotton, by being treated with a mixture of nitric and sulphuric acids. The nitro-cellulose thus produced is subsequently steeped in a solution of nitrate of potash. Thus the finished compound is similar in character to nitrated guncotton.
Nitro-glycerine Compounds. — Nitro-glycerine, the most powerful explosive used in industry, is formed by the action of narks acid upon glycerine at a low temperature; although the process of manufacture is very simple, still from the dangerous nature of the resulting product particular oars is ueceaaary, in order to conduct it without injury to those employed. The glycerine should be free from the adulteration often found in it, such as fatty acids or British gum, and of the greatest specific gravity possible, say at least 0.88. The nitric acid must be strong and very puro, haviug a specific gravity of not less than 1.45. As acid of this strength cannot ordinarily be obtained in the market, it must be prepared for the purpose by careful distillation from aodium nitrate and sulnburic acid. Before it is used the nitric acid is mixed with twice its weight of strong sulphuric acid. This does not take a direct part in the production of nitro-glycerine, but absorbs the water which is formed during the reaction, thus preventing dilution of the nitric acid.
Liecke prescribes the following formulas for manufacturing the three several preparations, mono-nitro-glycerine, di-nitro-glycerine, and tri-nitro-glycerine :—Mono-nitgo-glycerine ; dissolve 100 grammes of glycerine in 200 grammes of nitric acid, sp. gr. 1.3, and then add 200 cubic centi metres sulphuric acid, the product should be v Di-nitro-glycerine ; sulphuric acid, containing one equivalent of water, two volumes nitric acid, sp. gr. 1.4 one volume, mix the acids, lower the temperature to 0° (32° F.) or below, and drop into it one volume pure glycerine, product C31:1502H Tri-nitro-glycerine ; sulphuric acid 3.5 parts, nitrate of potash 1 part, cool to
2 NO' -18° (0° F.) produces KO + 4 6 HO, from this the concentrated fuming nitric acid is separated by decantation, and being maintained at -18° (0° F.). 0.8 parts pure glycerine is very gradually added, producing 2 NW/ The acids when mixed are placed together, in a receiver from which the mixture can be drawn as it is wanted. The apparatus employed for making nitro-glycerine on a comparatively small scale is shown in Figs. 619 to 621. A A are wooden troughs placed round a brick chimney D, and containing the earthenware pitchers a a, which hold the acid mixture. On the shelf B are arranged bottles b b, which contain the glycerine. These are loosely closed by wooden stoppers with broad rounded tops, having holes through which indiarubber tubes c c are passed, these tubes reaching to the bottom of the bottles, and carrying small glass nipples at their other end ; e e are conical wooden plugs, which are passed through the same holes as the rubber tubes. G is a steam pipe arranged on the shelves bb behind the glycerine bottles. The air main F passes under B, and carries on its lower side a number of small short pipes, two for each pitcher, to which the rubber tubes c Id, which hang over the pitchers, are attached, and in these are inserted glass tubes long enough to extend to the bottom of the pitchers. In the elevation these tubes are out of the pitchers, hut in the section they are in place as if in use.
The troughs are made tight in order to contain ice water, with which the pitchers are surrounded. Partitions with openings at the bottom are arranged at the corners f f of the troughs. These only contain water, and are convenient as affording opportunities for quickly emptying a pitcher into water, should this be come necessary. In one corner of the trough is a pipe, from which the water may be drawn off into the escape 1 when the operation is finished. The pitchers are arranged on narrow wooden strips, which raise them some two inches off the bottom ; thus the cold water has full access all round them, and when in position they are well under the overhanging hoods C C'. The hoods are flat wooden boxes, wide at the bottom but narrow at the top, where they fit into openings in the chimney D. At the lower part of the chimney a grate and fire door, not shown, is placed on the floor below.