VOL.3, No. 9
THGUSE on CHEMISTRY IN O m NATIONAL DERRNSR
1043
When this problem was first brought up the chemists knew that there was a vast supply of free nitrogen in the air if they could only find some way of getting it out and into some usable form. A process was worked out so that when an electric arc was passed through the air a nitrogenoxygen compound and water were formed, which united to form nitric acid. However, this electric arc method is five times as expensive as the cyanamide method which was discovered later. This process is the most practical which has been discovered and is used in the Muscle Shoals plant. The nitrate is formed by first making calcium carbide which acts with the nitrogen of the air to form cyanamide. With this process, evolved by the brains of onr chemists, put into practice a t the great Muscle Shoals plant the United States need never fear a war-time shortage of nitrates. This great supply of nitrates obtainable from the air can be used for many things beside war. The chemists and horticulturists have found that by adding nitrogen to the soil in one form or another the crop yield can be increased about 50 per cent. For this reason the farmers plant alfalfa and clover in worn-out land since both of these crops add nitrogen to the soil instead of taking it away. The supply of nitrates from Chilean deposits form so cheap a source that it is improbable that the present form of extracting nitrates from the air will ever be used to any great extent for crop fertilization, but i t is invaluable as an asset to have this great supply to draw upon in a time of need. This short discussion has been based upon the idea that chemistry has promoted the defense of the nation through military and industrial development. This alone is not all which chemistry has done. Military protection is necessary to industrial development, and on the other hand, prosperity due to the development of the nation's industries is necessary for carrying on military defense. Thus the uses of chemistry in both of these fields act and react with each other until chemistry becomes one of the most important factors in the nation's growth in its industrial and military defense. Fifty Tons of Iodine Made from Seaweed in 1925. The seaweed collected along the Breton coast brings in the tidy sum of 30,000,000francs yearly which at pre-war prices meant 85,000,000 a year. The first factory for the manufacture of iodine, its most valuable iroduct, though seaweed is also an important source for potassium and sodium, was established as long ago as 1829 at Conquet in Brittany. Since it takes a ton of fresh seaweed, approximately, to make a pound of iodine, according to figures given by M. Maurice Deschiens in a recent address before the French Society of Industrial Chemistry, the huge amount of seaweed necessary to make the 50 tons of iodine turned out in Brittany in 1925 causes its collectionand transportation to be one of the heavy factors of cost.-Science Service
