Certainly in one respect we had the advantage of the ancients in that we have nowadays at our disposal the modern alloy-steels of great resistance. An alloy of this kind having a thickness of 0.036 of an inch is able to stop at a distance of 10 feet a jacketed, automatic pistol ball, .45 caliber, traveling at the rate of 600 feet a second. This was important not only from the standpoint of helmet production, but from the further inference that body armor of such steel might still be profitably used. The records of the hospitals in France show that 7 or 8 of every 10 wounded soldiers were wounded by fragments of shell and other missiles which even thin armor plate would have kept out. The German troops used body armor in large numbers, each set weighing from 19 to 24 pounds. In this country we believed it possible to produce body armor which would not be difficult to carry and which would resist the impact of a machine-gun bullet at fairly close range. The production of helmets, however, was our first concern; and in order to be sure of a sufficient quantity of these protective headpieces, we adopted the British model for production in the United States and went ahead with it on a large scale. For the metal we adopted after much experimentation a steel alloy with a high percentage of manganese. This was practically the same as the steel of the British helmet. Its chief advantage was that it was easy to work in the metal presses in existence and it required no further tempering after leaving the stamping presses. Its hardness, however, wore away the stamping tools much more quickly than ordinary steel sheets would do. While we adopted the British helmet in design and substantially in metal used, we originated our own helmet lining. The lining was woven of cotton twine in meshes three-eighths of an inch square. This web, fitting tightly upon the wearer's head, evenly distributed the weight of the two-pound helmet, and in the same way distributed the force of any blow upon the helmet. The netting, together with small pieces of rubber around the edge of the lining, kept the helmet away from the head, so that even a relatively large dent could not reach the wearer's skull. It is an interesting fact that the linings for the American helmets were produced by concerns whose ordinary business was the manufacture of shoes. There were 10 of these companies taking such contracts. Steel for the helmet was rolled by the American Sheet & Tin Plate Co. The helmets were pressed and stamped into shape by seven companies which had done similar work before the war. These concerns were: Contractor. Delivered.