Page:Collier's New Encyclopedia v. 09.djvu/289

LEFT TANKS 245 TANKS BRITISH TANK — HEAVY TYPE together, with joints shielded from dirt and mud, with idler pulleys for laying the shoes down in front and driving sprockets for picking them up in the rear. The uprights on the inner surface of the shoes formed continuous rail-like bands upon which the truck wheels rolled carrying the weight of the machine. The mode of locomotion in the tractor and the tank is the same, each lays down its own rails and rolls over them. The track belts run lengthwise clear around the body, the shape bringing the additional track' surface into contact with the ground, and so distributing it that the pressure of a twelve-ton tractor per square inch is actually less than that of an ordinary man's shoe. The first ex- perimental tank weighed about 40 tons. Its noise and cumbersomeness greatly hindered its effectiveness, but the idea proved to be sound and mechanical experts worked hard to improve it. As time went on and the improvements were effected the personnel so engaged began to be very numerous and a separate tank corps was formed under a general officer. Later on in the war it was seen that the tank was to prove a decisive weapon. In the last phase of the war there was no other instrument that played a greater part in bringing victory to the side of the Allies. In 1916 a total of only 50 were shipped to France from the British FRENCH TANK — HEAVY TYPE