Page:Popular Science Monthly Volume 4.djvu/245

Rh has a residence, except by their consent, within the possibility of harm from an explosion in their works.

Thus, while such explosions are more or less frequent, the detonation of one of them, if it be not of special violence, excites only the passing remark of a dweller in the neighboring city of Wilmington, and never injures any one outside the works.

Not only is the general location selected, but the various buildings of these powder-manufactories are placed, in reference to the everpresent danger of an explosion. The works are not connected with one another in one great building, or in a connected series of buildings. They are built along the river-banks for over half a mile on either side, and with so much of distance between them that an explosion in one does not ordinarily communicate itself to another, and its destructive effects do not extend beyond the immediate vicinity of the building in which it occurred.

The buildings themselves are constructed carefully with reference to these accidents. They—at least those where the process of manufacture reaches the stage of danger—are built of stone, with three massive walls of solid masonry some ten or twelve feet thick. The fourth side, that which looks toward the river, is made of light framework. The roof is constructed as simply as possible, and is laid upon the walls, and not built into them.

The design of this method of construction may be readily seen. If an explosion occurs, the boarded roof and side of the building readily yield, and are blown into the river, while the massive walls of the other three sides withstand the shock. The building is like a huge mortar. By this additional precaution, the lateral effects of the explosion are prevented, and the buildings on either side are measurably protected.

These precautionary measures, however, are not always effectual. As a general thing—for explosions of greater or less violence are not infrequent—a single dull, heavy detonation is heard, and it is almost unnoticed by those residing in the neighborhood. If slight, it may readily be taken for the noise of a blast in the quarries near by. As, in certain stages of the manufacture, the machinery is set in motion, and the workman leaves the room when the danger is most imminent, life is not necessarily lost by the accident. The only harm that has occurred is the loss of the simple machinery, the materials, and the lighter portion of the building.

Sometimes the case is very different. I have a very vivid remembrance of one. It was the first and the most severe of which I had any experience.

I was sitting with some friends in the parlor of my house, at about eleven o'clock in the morning, when there came a sudden jar and a fearful shock of some very heavy body falling, as I thought, upon the piazza, which ran along the rear of the house. I started from my