Page:Popular Science Monthly Volume 80.djvu/47

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 The water is brought down 1,450 feet in these two pipes, furnishing 22,000 horsepower.

carbid, when heated in an atmosphere of nitrogen, absorbed the latter forming barium cyanid. But barium cyanid is expensive, so that the same experiment was carried out on the cheaper calcium carbid, now an article of commerce, in hope that calcium cyanid would be formed. Nitrogen was indeed absorbed, but half the carbon of the carbid was lost in the process, giving not calcium cyanid, but calcium cyanamid, which contains for each atom of calcium two atoms of nitrogen but only one of carbon. A study of this new substance revealed the fact that when put in water it was decomposed and all its nitrogen given off as ammonia. Now with the inadequate supply of ammonia from gasworks and the decreasing supply of nitrate from Chili, the world has been staring a fertilizer famine in the face, and every effort has been made to devise some way of combining the nitrogen of the atmosphere for the use of growing crops. Here in this new discovery was a possibility of manufacturing ammonia, needing for raw materials only limestone, coal and air, all cheap, and an electric furnace. The last could be only economically used when the electricity was furnished by water.

A few years ago a calcium carbid plant was established at Odda at the head of the Sör-fjord, one of the most beautiful branches of the Hardanger-fjord. To turn the carbid into cyanamid merely requires heating in an atmosphere of nitrogen, and nitrogen composes four-fifths of the air. But the problem of separating the oxygen and nitrogen of the air is by no means easy of solution on a large scale. Suffice