Up to the beginning of the summer of 1917 there was little accurate information in this country regarding the tanks. Somewhat hazy specifications then began to come from Europe about the designs of the different tanks at that particular time in use on the battle front, but these specifications were exceedingly rough and sketchy, consisting in the main of merely the fact that the machines should be able to cross trenches about 6 feet wide, that each should carry one heavy gun and two or three machine guns, and that their protection should consist of armor plate about five-eighths of an inch thick. [Illustration: THREE-TON TANK. Weight, 5,800 pounds; crew, two men (one gunner, one driver); power plant, two Ford motors, geared together, each motor driving one track; speed, nine miles per hour; climbing ability, 45°.] [Illustration: SIX-TON TANK. This machine is practically a copy of the French Renault tank and carries two men (one driver, one gunner). About half of these tanks were equipped with 37-millimeter cannon and about half with machine guns. Certain of these tanks also made with wireless apparatus substituted for the turret of the fighting tanks. Power plant, one Buda 4-cylinder motor; speed, five to six miles per hour; grade capacity, 45°; weight, 15,000 pounds.] With these facts as a guide, two experimental machines were decided upon, and work on them was begun immediately. With these machines it was determined to test the relative advantages of a specially articulated form of caterpillar tractor with wheeled traction, making use of very large wheels, and to develop the possibilities between the gas-electric and steam systems of propulsion. In September, 1917, decision had been made to supply the American Army with two types of tanks--one the large size, typical of that used by the British and capable of containing a dozen men, and the other a smaller one patterned after the French two-man model and known as the Renault. In September one of our officers charged with tank production was dispatched to Europe for a more intimate study of the machines used abroad and for the purpose of getting more detailed information respecting the merits of the various types of tanks, as well as to make arrangements for sending specimens here. The decision to equip the American forces in Europe with tanks of two sizes was made only after thorough and somewhat protracted conferences with British, French, and American officers in Europe. Complete drawings and samples of the small tank were obtained from the French and shipped to this country. As all of the drawings were made in accordance with the metric system of measurements, it was necessary before anything could be done toward actual production to remake the drawings, as the machine shops here were not equipped to use the metric system.