Page:Popular Science Monthly Volume 6.djvu/738

718 cargo, packed in such a manner, and containing such elements, that the barge was really a very efficient kind of torpedo. In her hold there were about five tons of gunpowder and a quantity of benzoline in kegs. This benzoline may be described as a very volatile species of petroleum. At ordinary temperatures it gives off a highly-inflammable vapor, and this, when mingled with the air in certain proportions, becomes explosive—the explosion running through it at the rate of about two feet per second when it is confined in a tube. In the case of the barge on the Regent's Canal, the cargo was closely covered with a tarpaulin, to protect it from the weather. From the moment, then, that this covering was put on by the bargemen, the vapor given off by the benzoline began to accumulate in the hold, and mingle with the air confined in the spaces between the various packages of the cargo. Thus the hold gradually became filled with a fiery explosive atmosphere, and all that was wanted to produce an explosion was contact with flame. In the little cabin, at the stem of the barge a fire was burning, and there was an aperture in the bulkhead, or partition, which divided the cabin from the hold. Through this the benzoline vapor entered the cabin, and the air in it was soon as vitiated as that under the tarpaulin in the hold. It was ignited by the fire; the explosion, beginning in the cabin, ran forward in a few seconds to the bow, and fired the gunpowder stowed there.

Every one knows what followed. Half London was awakened by the report, which was heard for miles around—to the northward as far as Finchley and Enfield, to the southward as far as Blackheath and Woolwich. Within a radius of from half a mile to a mile from the scene of the explosion houses were wrecked, windows blown in, doors burst open, ceilings shaken down, ornaments and furniture dashed to pieces. A massive bridge over the canal was destroyed, for hundreds of yards its embankment was displaced, and the house which stood nearest to it was so shaken that it had to be pulled down next day. The effect was more like that of a severe shock of an earthquake than any thing else. Fortunately no lives were lost except those of the crew of the barge, but the destruction of valuable property was enormous.

Much alarm has been caused not only in London but throughout the kingdom by this explosion in the heart of the metropolis, and it will have a useful effect in calling attention to the dangerous character of a material so largely employed as gunpowder, and the consequent necessity of carefully regulating its manufacture, storage, and transport, and seeing that these regulations are strictly enforced; for, no matter how perfect our precautions may be in theory, they are worse than useless if we cannot secure their practical efficiency. Without this, their only result must be to lull us into a false security. Gunpowder, and its manufacture and transport, are now subjects in which nearly every one is interested; and we purpose to devote the following