like you in the world—”

“Don’t be foolish, Jeff, but answer my question.”

“Well, mother, there are indeed some simple elements in creation, but dynamite is not one of them. It is composed of an excessively explosive oil named nitro-glycerine (itself a compound), and an earth called kieselguhr. The earth is not explosive, and is only mixed with the nitro-glycerine to render that liquid less dangerous; but the compound is named dynamite, in which form it is made up and sold in immense quantities for mining purposes. Here is some of it,” I added, pulling from my pocket a cartridge nearly two inches in length, and about an inch in diameter. “It is a soft, pasty substance, done up, as you see, in cartridge-paper, and this little thing, if properly fired, would blow a large boulder-stone to atoms.”

“Bless me, boy, be careful!” exclaimed my mother, pushing back her chair in some alarm.

“There is no danger,” I said, in reassuring tones, “for this cartridge, if opened out and set on fire by a spark or flame, would not, in the first place, light readily, and, in the second place, it would merely burn without exploding; but if I were to put a detonator inside and fire it by means of that, it would explode with a violence that far exceeds the force of gunpowder.”

“And what is this wonderful detonator, Jeff, that so excites the latent fury of the dynamite?”

I was much amused by the pat way in which my mother questioned me, and became more interested as I continued my explanation.

“You must know,” I said, “that many powders are violently explosive, and some more so than others. This violence of explosion is called detonation, by which is meant the almost instantaneous conversion of the ultimate molecules of an explosive compound (i.e. the whole concern) into gas.”

“I see; you mean that it goes off quickly,” said my mother, in a simple way that was eminently characteristic.

“Well, yes; but much more quickly than gunpowder does. It were better to say that a powder detonates when it all explodes at the same instant. Gunpowder appears to do so, but in reality it does not. One of the best detonators is fulminate of mercury. Detonating caps are therefore made of this, and one such cap put into the middle of that cartridge of dynamite and set fire to, by any means, would convert the cartridge itself into a detonator, and explode it with a 

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