The gun-recoil carriage, as the new invention was called, increases the rate of fire, since there is no delay in running up. The French were quick to develop this new feature, and set to work to make the rate of fire as high as possible. Up till then the ammunition fired from a field-gun had consisted of a shell, a bag of powder, and a friction-tube introduced through the vent to fire the charge. This was called a round of ammunition, and its complexity was increased by the fuse, which was carried separately and screwed into the shell when the round was prepared for loading, and afterwards set with a key to burst the shell at the required distance. The French combined the whole of these separate parts into one, so that a round of “fixed” ammunition, as now used, looks exactly like an enlarged rifle cartridge. (See Fig. 2.) Further, they did away with the cumbrous process of setting the fuse by hand, and introduced a machine which sets fuses as fast as the shell can be put into it. One of these machines is shown in Fig. 4. It is of a later pattern than that of the French service gun, being the one used by the Servians with their new gun made by the famous firm of Schneider of Creusot. The machine is set to the range ordered by the battery commander, the shell is dropped into it, and a turn of the handle sets the fuse. HOW A BIG GUN IS AIMED The independent line of sight is another modern device for facilitating the service of a gun. With this the gear for giving the gun the elevation necessary to carry a shell to the required distance is kept entirely separate from that used for pointing the gun at the target. The gun-layer has merely to keep his sighting telescope on the target, while another man puts on the range-elevation ordered by the battery commander. The result of all these improvements is that the best quick-firing guns (among which the French gun is still reckoned) are capable of firing twenty-five rounds a minute. The German field-gun is hardly capable of twenty rounds a minute, being an inferior weapon converted from the old breech-loader. But these high rates of fire are used only on emergency, as a gun firing twenty-five rounds a minute would exhaust the whole of the ammunition carried with it in the battery in three minutes.