The San Francisco call., 1898-03-20

Edward Simpson, U. S. N., WHO
 is an authority, writes that the
 term explosive is one applied to those substances, solid or liquid, which upon the application of heat or shock are converted either by combustion or decomposition into gases having many times the volume or the original substance. A low explosive, like gunpowder, is one which can be exploded by ignition. Further, the rate of this combustion can be regulated by mechanical treatment Thus, black gunpowder goes off quickly, like flash, whereas brown gunpowder burns as slowly as punk. Gunpowder is a me chanical mixture, as are all low ex- plosives; but high explosives, with which this article has to deal, are chemical compounds
 Gunpowder is the best known repre- sentative of the former, nitro -glycerine of the latter. High explosives are used where shattering and rending effects are to be produced, and they can be made to explode only by what is called deto- nation-that is, by s%suddenly shock ing or heating the surrounding high explosive that the mass is instantly chemically changed into gases many times greater than the original volume of the explosive, and this gas in its efforts to escape rips, tears, destroys annihilates anything and everything around or about it. The havoc it can work is terrific and irresistible.
 A great many kinds of high explo- sives have been compounded; in all those used for commercial purposes n1- tro-glycerine furnished the active prin- ciple. Nitro glycerine is formed by the action of concentrated nitric acid upon glycerine. It is a colorless, oily liquid having a pungent aromatic taste. It produces a violent temporary head ache if taken into the human system, either by placing a drop upon the tongue or on the skin, but when per sons habitually handle it they lose their susceptibility to this action.
 At temperature of 40 degrees Fah- renheit nitro glycerine freezes to a white crystalline mass, and 1t Is uSu- ally kept in this condition until ready to be used; it can be thus transported easily and safely. In it's liquid form it is dangerous to handle in any way. To bring it from its frozen state into the liquid form, the cans containing it are placed in hot water of a tempera- ture of 100 degrees. The point of firing Is 356 degrees.
 Nitro glycerine is the most powerful explosive agent in use; it can be fired by a fuse charged with illuminate of mercury. However, nitro glycerine in its pure state is rarely used for eXplo- sive purposes, principally because of it's dangerous nature. Three essentials are required in a high explosive, strength or disruptive power. safety in handling, and keeping qualities, and in their ef- forts to secure these many scientists have brought out different explosives.
 Dynamite, perhaps, is the name most familiar to people; it has become to a great extent generic, and means high explosive without consideration of the ingredients of which the compound may be manufactured. Dynamite, the gen. uine article to which the name was first given and by which in the army and navy 1t is still called, is a preparation made by mixing nitro glycerine with a natural silicious earth called kieselguhr or rotten stone, from which the water and organic substances have been driven out. The proportion of the mix ture is 75 per cent of nitro glycerine and 25 of rotten stone. The resulting compound is soft, of a pale brown col or, in general appearance and consist ency not unlike damp brown sugar.
 The rotten stone in dynamite proper Is replaced in other high explosives by some other substance which inventors claim adds certain specific qualities to the resultant. This absorbent is called g dope. It is this employment of this dope that renders dynamite safer to