The narrow beaten zone enables them to fire safely over the heads of advancing infantry from all ranges beyond 800 yards, provided the infantry are at least 200 yards from the enemy fired at. A study of the table of trajectory in the Appendix to _Manual of Military Training_ will enable the machine gunner to decide the circumstances under which the fire is safe in each case. Positions on the flanks and if possible to the front of the advancing infantry will render covering fire most effective, but these positions will rarely be possible. The first consideration is the concealment of the gun from the enemy’s artillery, which can easily silence them if exposed. It is also necessary that the positions selected should be sufficiently commanding to enable the battery commander to see the attacking infantry during the whole advance, so as to fire only when they are moving, while at the same time he must be able to see the position of the enemy’s trenches and thus direct the fire on any part desired. INDIRECT FIRE The best method of using covering fire in the early stages of the attack is by _indirect fire_ from the reverse slopes of a hill or from behind a ridge or other feature. This is not difficult to carry out and in no way lessens the accuracy of the fire or endangers the troops in front, as the following experiment will prove. EXPERIMENT IN INDIRECT FIRE The following is an extract from an article by First Lieutenant A. E. Phillips of the 10th Cavalry, from the _Journal_ of the United States Cavalry Association for July 1909: “To determine how many, if any, of the bullets from the machine gun would strike troops in front of an assumed ‘hill’ over which the gun was to fire, canvas frames were used to represent such objects, the targets being concealed from view. “The target consisted of a strip of target cloth 6 ft. high and 15 yards wide, along the bottom edge of which is pasted a row of kneeling figures with an interval of a yard from centre to centre. Across the target and parallel to its top edge was drawn a narrow black line tangent to the tops of the heads of the figures. Value of hits on any figure = 5; value of hits on the cloth below the line = 3; value of hits on the cloth above the line = 1. Canvas frame, 8 ft. high, placed 200 yards in front of the gun. Rapid fire: _First Experiment_ Range 800 yards -------+-------------------------------+----------------------------- | No. of Hits. | No. of +------+-------+-------+--------+ Remarks. shots. | Figs.| 5’s. | 3’s. | Total. | -------+------+-------+-------+--------+----------------------------- | | | | | 30 | 5 | 10 | 12 | 22 | Line of sight was 5 ft. 30 | 8 | 10 | 9 | 19 | below top of obstruction. | | | | | All shots over. -------+------+-------+-------+--------+-----------------------------