These trench mortars are used to hurl charges of high explosives varying from 25 to 100 pounds into the enemy's lines. They have a range of from 300 to 1,800 yards.
Plate 25b.—Improvised catapult.
Cover for Supports
At a variable distance to the rear of the first line fire trench is located the cover for supports, which is organized much in the same manner as the first line system of trenches and affords a second position in the system to fall back to in case of necessity. These trenches are provided with overhead cover and numerous dugouts for the protection of the men.
Machine Guns
At every available place throughout the defensive position machine guns are located, typical positions of which are shown in Plate 1.
The typical types of cover are shown in Plates 26 and 27.
Machine guns are a very potent factor in trench warfare. They are now being employed to a far greater extent than ever before, and the number is increasing on all the battle fronts as fast as they can be manufactured. The machine-gun positions are carefully concealed from the enemy, and fire is not opened until it is certain that it will be effective.
