The terrible gas and liquid fire bombs which the Germans were first reported using contained chemical compounds invented for the purpose by the chemists. Some of the chemicals and the gases produced when the bombs exploded were so powerful that men and animals in the range of the fumes were killed instantly. The effect was to paralyze them in some cases and it was reported that many of the soldiers were found dead standing upright in the trenches or in the attitudes which they had assumed at the moment they were overcome. BASIC PRINCIPLE OF BOMBS. Nitrous-oxide, or chlorine, in some chemical form is supposed to have been the base of the bombs, and concerning the liquid fire it was reported in connection with the dropping of bombs on London from a Zeppelin, that some of the bombs contained what is chemically known as Thermit, which is a mixture of aluminum and iron oxide used in brazing and welding. When ignited the oxygen is freed from the iron and combines with the aluminum with great rapidity. During the chemical reaction an intense heat is produced--a heat so great that it almost equals that of an electric arc. So in the world of agriculture and industry the German chemists, recognized leaders of the world, actually made or produced from the air and other unsuspected sources things without which they could not have withstood the siege against them for a single year. In the absence of concentrated foods for cattle and humans, the chemists produced absolute substitutes. They took the residue or waste from the breweries and extracting the bitter hops taste from the dried yeast produced a substitute for beef extract. So also they secured ammonium sulphate by a direct combination of nitrogen and hydrogen in the air. At the same time they utilized other minerals than those usually available for the manufacture of sulphuric acid and placed the country on an independent footing. But Germany was not alone in its advancement. The United States, which found itself without quantities of dye-stuffs and many other chemically produced things when the war came on, took the lesson unto itself and is today nearer self-supporting than it ever was in the history of the nation. The Department of Agriculture has experimented and produced from yeast, vegetable boullion cubes, which taste like beef extract and contain greater nutriment. DOMESTIC DYE-STUFFS.