_a_ _b_ _c_ Potassium chlorate 95 90 80 } Manganese dioxide 5 10 20 } Oxygen carrier, 92 to 87% 1 2 Nitro-benzene 50 60 } Turpentine 20 15 } Combustible, 8 to 13% Naphtha 30 25 } Any combination of _a_, _b_ or _c_ with 1 or 2 may be used. The amount of liquid combustible taken up may vary from 8 to 13 per cent.: this irregularity is a serious defect, and may cause incomplete detonation. This explosive is also made in Italy. =PROSPERIT= is a German ammonium nitrate explosive, containing also vegetable meal, nitro-compounds and other constituents. It may contain up to 4 per cent. of blasting gelatine. Gelatine-Prosperit contains also up to 20 per cent. of dinitro-chlorhydrin gelatinised with collodion cotton. =PULVÉRIN.=--An ungranulated black powder made in France for use in fireworks, etc. =PULVÉRITE.=--A Belgian coal-mine explosive containing perchlorate-- Ammonium nitrate 30·5 Potassium perchlorate 24 Nitroglycerine 6 Collodion cotton 0·5 Trinitro-toluene 7 Flour 5 Sodium chloride 18 Ammonium sulphate 7 Barium sulphate 2 The “charge limite” is 850 grammes, equivalent to 504 grammes of Dynamite No. 1. =PYROCOLLODION= is a nitrocotton almost entirely soluble in ether-alcohol, and of comparatively high nitration. It contains about 12·5 to 12·7 per cent. of nitrogen, and consequently has about enough oxygen to oxidise all its hydrogen to water, and its carbon to the monoxide. It was first prepared by Mendeléeff for the Russian smokeless powder, and was afterwards adopted by the United States for their present powder. =PYROXILINE= was a name formerly given to nitro-cellulose. =RACK-A-ROCK= is a Sprengel explosive which has been used extensively in America, and also in Siberia and China. It consists of cartridges of potassium chlorate mixed sometimes with oxide of iron, which are dipped shortly before use into a liquid. The latter is nitro-benzene or “dead oil,” a heavy hydrocarbon oil obtained from coal-tar, or a mixture of the two. The chlorate cartridges are enclosed in small cotton bags, and are placed in a wire basket suspended from a spring balance. They are dipped into a vessel containing the liquid until a quarter or a third of the weight of the chlorate has been taken up. =RASCHIT= is a blasting explosive consisting entirely of salts readily soluble in water, invented by F. Raschig. The incorporation is carried out by dissolving the constituents in water, and evaporating the solution rapidly on a rotating steam-heated drum. The oxidising substance is ammonium or sodium nitrate, and the combustible is the sodium salt of an organic sulphonate or the residue obtained from the manufacture of wood cellulose.