Page:Popular Science Monthly Volume 92.djvu/719

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���This remarkable picture, which looks so much like a glorious sunset or cloud effect, is in reality a great pile of coal in flames at Superior, Wis. It was finally put out with bicarbonate of soda

��Extinguishing Fires in Coal Piles with Bicarbonate of Soda

IT has long been known that as the re- sult of spontaneous combustion fires often originate in the interior of large coal piles, especially when the coal is fine and contains a large percentage of sulphur. Some of the recent coal-pile fires have demonstrated, however, that under favorable conditions spontaneous combustion is liable to take place even in piles composed of coal in large lumps. It depends principally upon the nature of the coal and upon the amount of rain to which the pile is exposed.

John A. Thomas, of Columbus, 0., who made a special study of spontaneous combustion, is the originator of a simple and effective method of extinguishing such coal fires. The application of his method has prevented enormous damage in several instances, where fire had originated in large accumulations of coal.

Mr. Thomas uses a strong solution of bicarbonate of soda, which he tnrows upon the burning coal-pile by means of a force pump. The carbon dioxide, released from the soda puts out the fire. The gas is assist- ed by the water which, by the heat of the burning coal, is transformed into steam.

The illustration shows the burning coal- pile at Superior, Wis. A considerable

��part of the 100,000 tons comprising this pile was saved by Mr. Thomas, after the fire had been raging more than three weeks in the interior of the pile.

Why It Is That Bricks Are Made with Straw

EVERYONE is familiar with the story of how Pharoah commanded his taskmakers to increase the burdens laid on the Israelites by withholding from them the straw wherewith to make bricks; and doubtless many have won- dered wherein the hardship lay. By most people, probably, the view has been held that the straw was added as a binding material, much as hair is used in mortar; but such an explanation is scarcely satis- fying when it is remembered that the straw fiber is a very weak one. Alexander Findlay says in his "Chemistry in the Ser- vice of Man" (Longmans, Green and Co.):

"About fourteen years ago it was found by Dr. E. G. Acheson, to whom we owe the discovery of carborundum and the process of making artificial i^iphite, that when clay is mixed with a cHhite solution of tannin, it becomes much more plastic, and the strength of the dried brick is, moreover, greatly increased. Although straw does not con- tiiin tannin, it was found that when straw is treated with water, the extract obtained has the same action on clay as tannin has, the plasticity of the clay and the hardness of the brick being greatly i!i creased."

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