(a) The construction of fake shelters and trenches from the material excavated from the "islands of resistance";

(b) The putting in repair of old abandoned trenches and making a show from time to time of activity in them;

(c) And as mentioned above, the location of the fundamental organs of defense outside of the visible trench system.

3. The terrain should be prepared to permit of the carrying out of immediate counter-attacks. In order that counterattacks may be delivered under favorable conditions, it is essential

(a) That the troops charged with their execution should not be exhausted by the artillery preparation. It is therefore necessary that they be provided with bomb-proof shelters. These shelters form the bases for the counterattacks which will be directed toward the "islands of resistance" or rather the intervals between them. These bases will be located, therefore, either in the open or in trenches, behind the "islands of resistance," at such distance as will permit of the prompt delivery of the counterattack, which is an indispensable condition.

(b) Machine guns placed in pits in the open and connected by telephone with the counter-attack base, should support the counter-attack either by a flanking fire or by preventing the enemy from coming out of the part of the works he has captured.

4. The importance of an organization such as has been described, calls for a carefully studied plan. Such a plan, approved by the corps commander and submitted to the army commander should not be subsequently changed without authority from the army commander.

S. M. E. FORTIFICATION CIRCULAR No. 16.

MACHINE GUN EMPLACEMENTS.

The following notes and 5 plates are intended to amplify the information given in "Notes for Infantry Officers on Trench Warfare," and in S. M. E. Fortification Circulars Nos. 11 and 13 on this subject. They are based on material received from overseas.

Siting.

1. The first point to be attended to in laying out a machine gun emplacement is to fix the exact position of the loophole, and the height of the bottom of the loophole above the ground.

2. When the field of fire is at all doubtful, alleys through parapets or other obstructions should be cut in at least two places in the arc of fire, in order that the exact height of the loophole may be verified before any other work is started.

3. Cross fire is better obtained from re-entrants than from salients.

Dimensions.

4. These are laid down in "Notes for Infantry Officers on Trench Warfare," Figs. 18, 19, 20, but doubt has been expressed as to whether the dimension 24 in. from bottom of loophole to ceiling is not excessive. When the Vickers Maxims are withdrawn it is thought that this dimension can be reduced to 15 in., and in any case reduced to 21 in.

5. When the emplacement is required to accommodate the detachment, a floor space of 6 ft. 6 in. by 7 ft. is found to suffice.

Design.

6. The table should be made of wood to suit the tripod mounting and sandbags added to take a muzzle-pivot traversing mounting. The space under the table is valuable for storage purposes.

7. Every strong emplacement should be fitted with a traversing mounting.