It may be said that there were but two nations in the great war which went to the Middle Ages for ideas as to protective armor--ourselves and Germany. The Germans, who applied science to almost every phase of warfare, did not neglect it here. Germany at the start consulted her experts on ancient armor and worked along lines which they suggested. The German helmet used in the trenches was undoubtedly superior to any other helmet given a practical use. The first helmets to be used in the great war were of French manufacture. They were designed by Gen. Adrien, and 2,000,000 of them were manufactured and issued to the French Army. These helmets were the product of hasty pioneer work, but the fact that they saved from 2 to 5 per cent of the normal casualties of such a war as was being fought at once impelled the other belligerents to adopt the idea. Great Britain, spurred by the necessity of producing quickly a helmet in quantity, designed the most simple helmet to manufacture, which could be pressed out of cold metal. [Illustration: INTERIOR AND EXTERIOR VIEWS OF THE STEEL HELMET WORN BY OUR TROOPS.] [Illustration: AVIATOR'S HELMET.] [Illustration: VISOR HELMET FOR SNIPERS AND MACHINE GUNNERS.] When America entered the war she had, naturally, no distinctive helmet; and the English type, being easiest to make, was adopted to fill the gap until we could design a more efficient one ourselves. Consequently 400,000 British helmets were bought in England and issued to the vanguard of the American Expeditionary Forces. Our men wore them, became accustomed to them, and came to feel that they were the badge of English-speaking troops. The British helmet thus became a habit with our men, one difficult to change, a fact which mitigated against the popularity of the more advanced and scientific models which we were to bring out. Now, the British helmet possessed some notable defects. It did not afford a maximum of protective area. The center of gravity was not so placed as to keep the helmet from wobbling. The lining was uncomfortable and disregarded the anatomy of the head. It was vulnerable at the concave surface where bowl and brim joined. It is not an astonishing circumstance that some of the earlier helmets worn by the men-at-arms of the days of knighthood possessed certain of these same defects, notably, that they were apt to be top-heavy and uncomfortable. Only by centuries of constant application and improvement were the armorers of the Middle Ages able to produce helmets which overcame these defects and which embodied all of the principles of defense and strength which science could put into them. The best medieval helmets stand at the summit of the art. It was the constant aim of the modern specialist, aided by the facilities of the twentieth century industries, to produce helmets as perfect technically as those rare models which are the pride of museums and collectors.