iv. From his observing station the battery commander, having fixed the

compass on the No. 3 director, measures the angle which the direction of the target makes with magnetic North, and after making the necessary correction for displacement sends this angle down to the battery as ... degrees Right or Left of magnetic North.

The officer working the battery director, having fixed his compass to the director, sets the director at the angle ordered with reference to magnetic North and the subsequent procedure is as in i or ii.[19]

[19] At present this procedure is only possible with batteries provided with two No. 3 directors.

3. In each method the aiming point is laid on, either through the No. 7 dial sight or over the No. 1 dial sight, or else auxiliary aiming points are picked up and laid on, from round to round. Should aiming posts be used, they are planted in line with the No. 7 dial sight, or the rocking bar, or gun sights set at zero.

4. To obtain parallel lines of fire to that of a gun whose line is correct, the battery commander gives the order “PARALLEL LINES TO NO ________” The dial sight of the named gun is used as a director, and lines obtained as in method i.

5. In the case of guns which are not provided with dial or panoramic sights, but with gun arcs, or the shields graduated as gun arcs, slight modifications of the three methods mentioned above are necessary.