When tested in a gallery with an explosive gas mixture I. proved to be safer than the other two. =GIANT COAL-MINE POWDERS= are American coal-mine explosives on the Permissible List. No. 5 is an ammonium nitrate explosive, whereas Nos. 6, 7 and 8 are low-grade dynamites mixed with hydrated salts. =GIANT POWDER= is a name given in America to dynamite. No. 1 is a kieselguhr dynamite containing about 75 per cent. of nitroglycerine. Many varieties, however, do not contain kieselguhr, but consist of nitroglycerine mixed with wood pulp, sodium or potassium nitrate, resin, sulphur or other combustible matter. The nitroglycerine is sometimes gelatinised with collodion cotton, or in the “Extra” varieties is partially replaced by ammonium nitrate. =GLONOINE= was an early name for nitroglycerine. =GLUECKAUF.=--A German explosive of the Grisounite type consisting of ammonium nitrate and vegetable meal, to which might be added any of the following: sugar, resin, fatty oil, potassium nitrate, sodium nitrate, dinitro-benzene, ammonium oxalate, copper oxalate, copper nitrate ammonia, or sodium chloride. It was used for a time by several potash mines; was given up again by most of them. =GOOD LUCK= was an explosive made by the Sprengstoffwerke Glueckauf A.-G., and was on the old British Permitted List for coal-mine explosives. It had the composition-- Ammonium nitrate 82·5 Dinitro-benzene 1 Turmeric 10·5 Copper oxalate 6 =GRANATFUELLUNG= (_i. e._ Shell-filling) is a name given by the Germans to certain high explosives used for filling shell. Granatfuellung C/88 is picric acid, and C/02 is trinitro-toluene. See Fuellpulver. Other substances used in German shell and bombs are trinitro-anisole, dinitro-benzene, hexanitro-diphenylamine and hexanitro-diphenyl sulphide, otherwise picryl sulphide. =GRISOUNITE.=--A French coal-mine explosive. See =FAVIER= Explosives. =GRISOUTINE= or =GRISOU-DYNAMINE= is the only explosive except Grisounite allowed in the more dangerous French coal mines. It consists of ammonium nitrate mixed with blasting gelatine. As the State monopoly does not extend to explosives containing nitroglycerine, it is made by private firms, but the compositions are regulated by the “Commission des Substances Explosives,” which in 1911 resolved that they should be uniformly as follows-- Couche au Roche au Couche. Salpêtre. Roche. Salpêtre. Nitroglycerine 12 12 29 29 Collodion cotton 0·5 0·5 1 1 Ammonium nitrate 87·5 82·5 70 65 Potassium nitrate -- 5 -- 5 The calculated temperatures of explosion of the Grisoutines couches are below 1500°, and those of the Grisoutines roches below 1900°. The addition of 5 per cent. of potassium nitrate is found to increase the safety.