Page:Popular Science Monthly Volume 85.djvu/588

584 The science of fertilizing achieved the amazing result that Germany's soil, although cultivated for almost two thousand years, is to-day more productive than the virgin soil of the United States and Canada. Deserted farms like those of the New England States and the state of New York are unknown in the Empire. Chemistry is not only educating the farmer in scientific fertilizing but producing the requisite artificial fertilizers, and here again German militarism in its farsightedness has brought about most astonishing revolutions.

Of greatest importance in agriculture are nitrogenous fertilizers, that is, artificial manure which introduces nitrogen into the soil. The chief material for this purpose is nitrate of soda, which, as saltpeter, is imported in large quantities from South America. Unfortunately, this substance is also the sole raw material for the manufacture of nitric acid, and nitric acid is the chief material for the manufacture of all kinds of explosives. The French and English employ picric acid, which is trinitrophenol (lyddite, melinit) and is made by the action of nitric acid on carbolic acid. The Germans are using as their chief explosive trinitrotoluol (tritolyl), which is produced from toluol, a coaltar hydrocarbon, and nitric acid.

German militarism realized that two great dangers might arise from these applications of saltpeter. In time of war the importation of saltpeter might be stopped by the navy of a foreign nation, and it might therefore become impossible to manufacture nitric acid and explosives. The feeding of the nation might be interfered with, inasmuch as the soil could not be properly fertilized, and hence could not produce sufficient food-stuff's. Therefore, it became imperative that the nation must become independent of the importation of saltpeter.

The problem was solved by the utilization of nitrogen from the air, and in this way nitric acid was produced without saltpeter as a starting material. Unfortunately, however, the available processes can be carried out economically only in localities where cheap power is available, which to-day means countries where water power is abundant. Since Germany has hardly any waterfalls, and therefore is very poor in power created in this manner, the plants for the manufacture of nitric acid by utilizing the nitrogen from air were mostly established in Norway—a foreign country. The problem was therefore only half solved. But soon by the direct union of nitrogen and hydrogen, as accomplished by the ingenious synthesis of Haber, an absolutely independent source for nitrogenous fertilizers and nitric acid was created within the German Empire. The raw materials for the Haber synthesis—nitrogen from the atmospheric air and hydrogen from water gas—are obtainable in unlimited quantities in the country. In the Haber synthesis ammonia is first produced which, in the form of the sulphate of ammonium, is as efficient a fertilizing material as saltpeter. This method, however, has