9. Identifications.
The importance of passing on all identifications as speedily as possible to Corps "I" cannot be too strongly impressed on all concerned. It is essential that special efforts be made to wire at once, as soon as identifications are made and the locality in which obtained.
10. Maps and Photographs.
The following maps are being issued:
(i) A large issue of 1/20,000 No. 62.D. South-East regular series for distribution to all officers.
(ii) 1/20,000 Map Message Form, for distribution down to N.C.O.'s.
(iii) A small issue of 1/10,000 Maps of forward area only.
(iv) 1/20,000 Barrage Map, for distribution down to Company Commanders.
(v) 1/40,000 Organization Map, together with notes on the enemy.
The following special photographs are being issued:
(a) A Mosaic of each Divisional front, squared and contoured and freely annotated, for distribution down to N.C.O.'s.
(b) Oblique Photographs of each Divisional front, for distribution to all officers.
Battle Instructions No. 11
CO-OPERATION OF INFANTRY AND AIRCRAFT
1. Contact Aeroplanes.
(i) Indication of position by flares.
(a) Red ground flares will be used to indicate the infantry positions to contact aeroplanes. They will be lit by infantry in the most advanced line only.
(b) A contact aeroplane will fly along the line of the first objective at zero plus 2 hours 30 minutes. Flares will be called for by the aeroplane sounding a succession of "A's" on the Klaxon horn and by firing a white Very Light. If the aeroplane fails to mark the line accurately, it will repeat its call ten minutes later.
Should the infantry not have reached the line of the objective at the time laid down above, the contact aeroplane will return at half-hour intervals until flares are shown.
(c) A contact aeroplane will fly along the line of the second objective at zero plus 6 hours 30 minutes. It will call for flares, and the same procedure will be followed on this objective as on the first objective until the flares are seen.
(d) A contact aeroplane will fly over third objective at zero plus 7 hours, when the procedure laid down for the first objective will be observed until the flares are shown.
(e) Divisions will organize message-dropping stations in the vicinity of their Headquarters.
(ii) Other means of identifying the position of the Infantry.
(a) Rifles.—Three or four rifles laid parallel across the top of the trench.
(b) Metal Discs.—Metal discs will be used as reflectors by flashing in the sun. This method has been successful even on days which have not been particularly bright.
The disc is most easily carried sewn to the Small Box Respirator, and can be used in this way without inconvenience.
2. Counter-attack Planes.
(a) From zero hour counter-attack planes will be constantly in the air, with the object of observing hostile concentrations or abnormal movement.
(b) In the event of an enemy concentration indicating a counter-attack, the counter-attack aeroplane will signal this information to the Artillery by wireless. In the case of a counter-attack actually developing a white parachute flare will be fired by the aeroplane in the direction of the troops moving for the impending counter-attack, for the information of the Infantry.
3. Ammunition-carrying Aeroplanes.
(a) Aeroplanes will be detailed to transport ammunition from zero plus 2 hours 30 minutes.
(b) Vickers guns will display a white "V" at the point where ammunition is to be dropped. The arms of the "V" to be 6 feet in length and 1 foot in width. The apex of the "V" to point towards the enemy.
(c) Ammunition aeroplanes will have the under-side of the lower planes painted black for a distance of 2½ feet from the tips.