He claimed for blasting gelatin that, in addition to being the strongest, it was absolutely the safest explosive known. In proof of this he devised a series of experiments which have been often performed at the factory and which have never failed. They may be seen at any time by a visitor whom the company desires to convince, and as given on a late occasion were as follows:

1. A cube of iron weighing 420 pounds was hoisted on crossed poles above an ordinary packing box containing fifty pounds of dynamite cartridges, the box resting on a board on the ground. The rope was cut by electrically exploding a cartridge against it, and the weight fell twenty-five feet, smashing the box completely and pulverizing some of the cartridges; but there was no explosion.

2. The same experiment was repeated with a box of blasting gelatin cartridges, the fall being twenty-five feet and the iron weight 470 pounds. Box and contents were crushed and scattered, but there was no explosion.

3. A one pound tin of gunpowder was placed on an open five pound box of dynamite cartridges and exploded. The dynamite caught fire and burned up, but did not explode.

4. The same experiment was performed with a five pound box of blasting gelatin cartridges with the same result.

5. A dynamite cartridge was set on fire by a fuse, and burned rather rapidly. It would have burned away completely, but a detonator had been placed in the middle, and when the flames reached this the other half of the cartridge exploded.

6. To show the strictly local force of dynamite, a one pound cartridge was hung eight inches above a three-eighths of an inch boiler-plate, which was lying on two bits of wood and exploded. The plate was only slightly bent.

7. A similar cartridge was laid flat upon the same plate and exploded, the result being a hole torn in the plate about the size of the cartridge.

8. A similar cartridge was then placed on a similar plate and covered with sand. Upon exploding, it tore a large hole in the plate.

Dynamite and blasting gelatin when set on fire will merely burn away without danger. If compressed, both will burn until the heat reaches a point high enough to explode the remainder, but this always requires sufficient time to give bystanders full warning and enable them to reach a point of safety.

Interior of barn-like building where nitro-cotton is made

The explosive force of No. 1 dynamite, weight for weight, is four times that of gunpowder. Bulk for bulk, the dynamite being much heavier, it is over seven times as powerful as gunpowder. Blasting gelatin has nearly six times, weight for weight, and a fraction less than ten times, bulk, the power of gunpowder. Gun-cotton and No.1 dynamite are about equal in explosive strength.

Dynamite is not allowed on passenger trains in England, but is transported with great freedom on the continent, and thirty thousand tons of it have been shipped on the English and Continental railways without accident to date. Of course, every package and case carry explicit instructions, but that the danger is small the immunity from explosions in transport clearly shows.

The moral of which is, that dynamite is safe and blasting gelatin is safer if they are treated with only reasonable care. The accidents do not occur here but in the use of it, says Mr. Johnston. If the company’s explicit printed instructions were followed, accidents would scarcely be known. Accidents often occur in thawing after an explosive has been frozen; but these arise from the incredible recklessness of miners.