THE CAUSE OF DEADLY EXPLOSIONS.

THE CAUSE OF DEADLY EXPLOSIONS

这并不总是可能的学习是什么原因导致的explosion. It has been argued that a recent fire in Elmira, N. Y., was caused by a gas explosion. Hut it is doubtful if gas alone would cause one so destructive. However, an accumulation of dust exploding with the gas would do just such destructive work. Explosions of dust have been the cause of severe accidents. One of the effects of these calamities has been to recall to observant minds the fact that many materials are in pulverized form explosives of exceedingly high power. Not only coal, as is shown in frequent explosions in mines, but the powder from grain and sawdust will cause destructive explosions, and play great havoc. Thorough understanding of the subject of dust explosion is comparatively new. Cass L. Kenincott, a noted chemist, is one of the authorities on the phenomenon, having treated it exhaustively in papers read before the academics of science, and more popularly in expert testimony once given before a jury.

Any explosive (Mr. Kennicott said) is a rapid combustion of a highty combustible material. The explosion of gunpowder, for instance, is nothing more than this. The consequent expanding tendency is so sudden that impending objects are given a violent impulse; in a gun the load is given a rapid start. As any explosion may be called a rapid combustion, ordinary combustion may, on the other hand, be considered as a slow explosion. The chemical action in the two instances differs only in point of time; in either case it is simply a combustion of the combustible body with the oxygen of the air. Now, it is evident that in general the ispidity of the burning will increase with the number of parts into which the combustible is divided. A log is placed upon a fire; it burns more or less slowly until at length the constituents of the wood have united with the oxygen of the air. If the log had been split into cordwood, the burning would have taken place ina much shorter time. If the cordwood were split into kindling wood and piled so that the air had free access, the burning would take place still more rapidly. If the wood were ground into powder—powder so fine that it would float in the air—combustion would take place so rapidly as to result in an explosion. So powerful is the influence of the division that many substances which in bulk are either relatively non-combustible or to be ignited only with considerable difficulty, are. when in a fine state of division, readily ignitible. As an example of a substance not combustible in the ordinary sense of the term, iron may be taken. When finely divided either into filings or by the process of rusting, it burns readily.