ii. When the director is behind the battery the gun layer must lay back

on the director. As the large angles cannot be read on the gun arc the officer laying out the lines of fire will, after clamping the director at zero on the target, align it backsight--foresight on the centre of each breech and give out the angles.

6. If the direction of the target cannot be obtained from a position near that selected for the battery and the distance of the observing station is too great to render any of the above methods available, the battery commander as soon as he has completed his reconnaissance and pointed out the approximate position of the battery to the battery leader, returns to his observing station; where he has previously left his range-takers, signallers, and such other portions of his headquarters as he requires.

Communication is at once opened up, the signallers taking care to keep under cover. The telephone if available is laid between the battery and the observing station. The range-takers take the range to the target, and to the battery (if the “sub-base,” para. 7, is not used), and afterwards to other objects in the field of fire.

The battery commander sets up his director under cover and measures the angle between the battery and the target.

When necessary, a flag is placed on the battery director, but the observing station director should be rendered conspicuous in some other manner.

He then works out by means of the plotter the battery angle (T B O in Fig. 30) and the range from the battery to the target, and communicates them to the battery leader, =taking care that the battery angle is sent down right or left according as the target is right or left of the line joining the battery and the observing station= (B O in Fig. 30). He then calculates the angle of sight and communicates it to the battery leader.

If the dial sight is used, it is set at the battery angle, and when laid on the observing station director the gun is in the line of fire. If the director is used, it is set at the battery angle and laid on the observing station director; the direction of the target is shown, when the arrow head is brought to zero.

The direction of the target having been obtained at the battery, lines of fire for the guns can be given by one of the methods described above.

7. The distance from the observing station to the battery can be rapidly measured by the use of a sub-base at the battery. An aiming post or signalling flag, F (_see_ Fig. 30) having been placed at a convenient distance, 20 to 50 yards, from the battery director and at right angles to the line B O, the angle that this base subtends at O is measured with the director and the range deduced from the formula:--

6 Sub-base in yards ---- × --------------------- = Base in hundreds of yards. 10 Apex angle in degrees

8. Should preparations for opening fire be required and no target be visible, a suitable reference point in the enemy’s position is selected and lines of fire laid out to this point.

The switch angles, ranges, and angles of sight to all points on which fire may have to be directed are then ascertained, and all other preparations made which will conduce to fire being opened as quickly as possible when required.

The fire is controlled and the ranging carried out in the ordinary manner by the battery commander.

If the observing station is so far from the battery or the intervening ground so broken that in case of emergency it would be difficult for the commander of the battery to reach the guns in time, it may be necessary for him to remain with the guns and to detail another officer to control the fire. (_See_ Sec. =199=(2).)

(b) _In an open or a semi-covered position._

9. In an open or semi-covered position where the target can be seen by the section commanders standing up, the target and its extent may be indicated:--