Although it is now widely recognized that coal dust is explosive, the fact that other carbonaceous dusts also are easily ignited and capable of explosion is not so well known. An expert of the Bureau of Chemistry6 in Washington has noted that while most of the dust explosions reported in surface plants occur in mills and elevators handling wheat, oats, corn and their products, it appears that no mill handling carbonaceous material is immune from the possibility of an explosion. The list of known explosions in other kinds of mills includes those handling dextrin, sugar, starch, malt, wood, linseed meal, cottonseed meal, paper, cork, fertilizer, sulphur, cocoa, and spice dusts.
There is a pronounced similarity between the explosion caused by gas and that caused by dust. A flame attains a high velocity in certain gas mixtures in which the oxygen is intimately mixed with the gas molecules. In the case