1st order.—Detonations.
2nd order.—Simple explosions.
Simple explosions are produced by direct inflammation, or by a small charge of gunpowder.
Detonations are obtained from nitro-glycerine, gun-cotton, &c., by exploding with fulminate of mercury.
They state that fulminate of mercury does not detonate gunpowder; but if the exploding charge is a small amount of nitro-glycerine, itself detonated by fulminate of mercury, then an explosion of the first order is obtained.
The relative effects were approximately measured by determining the quantities necessary to rupture small cast iron shells of supposed equal strength.
Results of their Experiments.—The following are some of the results:—
| Explosive Effect. | ||
| 2nd Order. | 1st Order. | |
| Gunpowder | 1·00 | 4·34 |
| Gun-cotton | 3·00 | 6·46 |
| Nitro-glycerine | 4·80 | 10·13 |
According to the above table, nitro-glycerine is more than ten times, and gun-cotton more than six times, as powerful as gunpowder fired in the ordinary way (2nd order).
The want of reciprocity between two detonating agents is shown in a remarkable degree by the following experiments, carried out by Professor Abel:—