In the food crisis which confronted the nations, chemists drew from the very air and the waters of the river and sea, gases and salts to take the place of those which became limited in their supply because of the demands of the belligerents.

The chemist is one of those who fights the battles at home. The resisting steel, the penetrating shell, the poisonous gas, the power-producing oil, the powerful explosive—all these are his contributions to the war's equipment, but he also is the magician who waves the wand and out of the apparently useless weeds and vegetable matter produces edibles. He turns waste products into valuable chemicals or extracts needed chemicals from by-products.

GERMANY'S GREAT PRIVATION.

Germany, deprived of many imports by the sea power of England, first transformed herself into a self-supporting nation through the agency of the chemist. Substitutes had to be provided for food products which the Germans could not get, and it is said that the ability of the Kaiser and his henchmen to withstand the attacks of the Allied forces was due as much to the service rendered by the chemists as by the army and navy.

Not only were artificial foodstuffs manufactured, but natural food products previously neglected were prepared for use. What had been regarded as useless weeds were found to possess food value. A dozen wild-growing plants were found that might be used as a substitute for spinach, while half a dozen others were shown to be good substitutes for salads. Starches were obtained from roots, and cheap grades of oils and fatty wastes of all sorts were turned into edibles.

Up until the advent of the present war cotton formed the base of most of the so-called propellant explosives used in advanced warfare. Such terrible explosives as trinitrotoluene occasionally mentioned in the published war reports, as well as many others, have as the principal agent of destructive force guncotton, which is ordinary raw cotton or cellulose treated with nitric or sulphuric acid, though there are, of course, other chemicals used in compounding the various forms of deadly explosives.

At the same time there are innumerable explosives which are of a distinct class. Lyddite, mentioned occasionally as one of the modern death-dealing explosives, has for a base picric acid. The Lyddite shells referred to occasionally in various articles about the war are shells in which Lyddite is used as the explosive. The largest percentage of explosives used in modern gunnery are those formed of nitrated cellulose—guncotton.

TWO GREAT FACTORS.

Therefore any shortage in the supply of cotton and cellulose is a serious matter in war time, for the country which has the most plentiful supply of ammunition is the one that has the greatest relative advantage. It was, for instance, stated from Washington several times after the war started and the United States commercial and industrial forces were being mobilized, that America could make enough almost unbelievably powerful explosives to blow Germany off the face of the European map, were it possible to transport the dangerous materials. Dozens of new explosive compounds were placed before the Government for consideration and in application for patents. One of the new ones, it was said, was so powerful that little more than a pinch of it exploded beneath such an immense structure as the Woolworth Building, New York, would destroy the entire edifice.

The curtailment of the supply of cotton to Germany when the war started, because of England's blockade, and later when America entered the conflict, threatened disaster to the "Fatherland." The German chemists began working immediately to supply substitutes for cotton, to be used both in the manufacture of explosives and fabrics. They developed the processes of producing cellulose from wood pulp to take the place of cotton for making guncotton, and certain forms of wood fiber and paper were used in the textile trades. Willow bark was one of the substances utilized to a limited degree in making fabrics.