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 change barrels, and constitutes a considerable weight. If cooling the barrel by means of water were to be dispensed with, the accuracy of the piece would rapidly diminish, and, after 1000 rounds of continuous fire, bullets would tumble even at short ranges. At the present time water is still the most effective means of cooling the barrel.

Machine guns fire ordinary small arms ammunition carried in loops on a canvass belt (weighing 1 kg. when empty), which is generally capable of holding 250 rounds of 8 mm. cartridges weighing 8.315 kg. These belts are very carefully manufactured, the material being shrunk, so as to prevent their shrinking when in use. Two men can refill an empty belt with 8 mm. cartridges in seven minutes, according to Swedish experiments, while a belt filling machine can refill one in a still shorter time. The rate of fire of machine guns is approximately 500 rounds per minute. They are variously mounted, according to circumstances, on sleds (in which the gun rests on a frame similar to that of a wheelbarrow), on tripods, or, for mountain warfare, on basket frames. Although the greatest readiness for firing was obtained with guns mounted on cavalry carriages (two-wheeled carts, similar to limbers, and equipped with shafts), which also permitted the greatest amount of ammunition to be carried along, these guns offered such a high target that their use, in an infantry action, was entirely out of the question, leading only to their being quickly silenced. Another defect was that the guns were unable to follow immediately upon the heels of the organization to which they were attached. Guns mounted on light tripods possess the least readiness for firing, as the gun must be dismounted during each change of position; but tripods are in-*