=Dynamite.= Dynamite is the most generally used of any blasting material in the world. It was invented in 1866 by Alfred Nobel. Its principal consisted in using an absorbent commonly called a “dope,” which would take up the nitro-glycerine and hold it after the manner of a sponge. A suitable dope should possess a cellular structure so that the nitro-glycerine may be subdivided into minute globules, each being held separately in its own cell, completely isolated from every other. In this condition its sensitiveness is greatly reduced, depending, of course, on the amount of nitro-glycerine absorbed. Dynamite may be classified, according to the nature of the absorbent used, as follows:-- 1. Dynamites with inert base, (Kieselguhr, Magnesium carbonate.) 2. Dynamite with an active base, (a) Combustible base. (b) Explosive base. The explosives’ bases in (b), as above, may be of the nitro-substitution class, or the nitric-derivative class. In choosing the dopes for inert bases of dynamite where wood pulp or sawdust is employed, it should be of some porous wood such as spruce or basswood. Woods differ considerably in the amount of nitro-glycerine they will absorb, ranging from 60% to 85%. Before introducing the nitro-glycerine they should be thoroughly dried. Good dynamite should not feel greasy. There should be no trace of free nitro-glycerine inside the wrapper of the cartridge. Slowly heated dynamite explodes at a temperature of 356 deg. F. If rapidly heated, it explodes at 446 deg. F. These temperatures apply only to Kieselghur dynamite. The American dynamites containing wood pulp and nitrates will explode with somewhat lower temperatures. Like nitro-glycerine it is most sensitive to shock and friction just above the freezing point. According to the dope used, it freezes at from 42 deg. F. to 46 deg. F. It is nearly, but not quite, insensitive to shock or friction when frozen. (See page 88, Manual of Field Engineering.) =Monobel.= Monobel consists of: Nitro-Glycerine 7-1/2% to 9-1/2% Nitrate of Amm. 66 % to 70 % Wood meal 7 % to 9 % Chloride of Sodium 14 % to 16 % Rem. Moisture 1/2% to 2 %