A considerable part of the needs of our co-belligerents for propellants and explosives was being met in the United States when we entered the war and it was necessary that we provide our own supplies without interfering with this production for them. In all, four nitrate plants were constructed or started, and work upon them was rushed as fast as the supply of labor and materials made possible, while extensions and additions were made to existing facilities. Many scientists and technologists constantly carried on experimental and research work upon processes for the fixation of atmospheric nitrogen and other problems connected with the supply of nitrates, and always with the aim in view of developing methods that would have economic as well as military value. The results were such as to make the nation for the first time in its history independent of any foreign country for the charge in the guns of its soldiers and also to bring much nearer the day when the United States would be independent of the nitrate deposits in foreign lands for its commercial and agricultural needs. The toluol for the manufacture of nearly all of the TNT used in loading high explosive shells was recovered as a by-product in the manufacture of illuminating gas. At the works of twenty-eight gas companies in different parts of the country plants were constructed, placed in the charge of experts and skilled workers and kept under the closest and most vigilant guard for the recovery of this important product, of which hundreds of thousands of gallons were necessary. As a result of the measures taken and rushed through, the supply of propellant and explosive material needed by our war associates was not interfered with and the loading of American ammunition was not delayed. The hideousness of war was immeasurably increased during the world conflict by the new uses that were made of chemical science. When these new applications of the death-dealing possibilities of chemistry were first made by the German army the civilized world drew back, horrified and appalled. But when a barbarous foe makes savage use of science those who are fighting him must, in sheer self-defense, meet him with similar weapons. Therefore, when America became a belligerent, averse as all her people were to the use of such weapons, regard for the safety of her troops at the front made it necessary to prepare for this peculiarly hideous and detestable form of war. As with other munitions, the industry to produce the implements of chemical warfare had first to be created. The Government built great plants and the immediate need stimulated scientific investigation, with results that were like a tale of magic, so rapidly did these and contributory chemical industries grow.