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 another as required. Shields should be used with all stationary mountings, but must be detachable, and should not be placed in position until required, as they indicate the situation of the gun and are easily destroyed by artillery.

The positions for machine-gun mountings in a fort must depend on the size and construction of the work, the nature of the outer defences, and particularly on the supporting works in the immediate vicinity. Positions commanding the glacis and the entanglements, on salients of works and enfilading ditches, and any dead ground where the enemy may effect a lodgment, are suitable. Counterscarp galleries at the angles of works flanking the ditch should invariably have machine-gun positions, with a special loop-hole, long and shallow, to enable them to sweep a wide area with fire.

The selection of the positions for machine guns in permanent works belongs to the art of the engineer, and there is little that can be said of their tactical employment. Fire should be reserved until the attack has reached close range, and then only opened when the target is large and vulnerable. Guns must be concealed by every possible device and all the loopholes must be blinded. By night all guns should be mounted and trained to sweep ground by which the enemy must approach; when searchlights are not in use, the elevation should be checked by the use of a clinometer and the amount of traverse may be shown by chalk lines on the