21st Divisional Artillery Instruction June 1916

Cooperation with aeroplanes.

Digest of XV Corps R.A. 15/CA9/10
System suggested.

1. Country be divided into zones 2000 Yds by 6000x these in Map Square F say would be divided thus
1 2 3 4 5 6
7 8 9 10 11 12
13 14 15 16 17 18
19 20 21 22 23 24
25 26 27 28 29 30
31 32 33 34 35 36

2. Country divided into zones 3000x X 3000x

1 2 3 x 4 5 6
A B

C D

Then case 2. If aeroplane sees a target at pt x he sends call F.A. Inf in map F.3.B28 etc. the B.C. knows what country he is covering & so tells operator to work out for calls according to his Square.