2. The scouts should be sufficiently far in advance of, and on the exposed flanks of, the firing-line, to protect it from surprise. In close or undulating country it will be necessary to provide for connecting links in order that there may be no danger of touch with the advanced scouts being lost, and of reports, verbal or by signal, failing to reach the commanders of the firing-line. In wooded country the distance may be decreased. 3. In close country, and in wood-fighting, the distances between the several bodies into which an attacking force is divided should seldom exceed 200 yards. In open ground greater distances are necessary, except against a badly-armed enemy. 4. The distance of the general reserve should be usually greater than that between the other bodies in order that it may not be prematurely drawn into the fight. 5. The general rule is that the troops in rear should be brought closer to the firing-line, the nearer the moment for the assault approaches. =147.= _Intervals._ An arbitrary rule as regards intervals is undesirable. Each portion of the force engaged will generally be told off to attack a particular section of the enemy’s line, and the frontage to be occupied by each left to the discretion of their commanding officers. It is essential that there should be a clear understanding as to responsbility for searching, and, if necessary, clearing, all dangerous ground which lies between units. This should be notified in the orders for attack. =148.= _Direction and Pace._ 1. Each unit should be given a point to move on. Nevertheless, in moving through woods, or over ground so close that it is impracticable to fix a point to march upon, a unit of direction, which should march by compass bearing, or by some well-defined landmark, such as a road or stream, is the only means of avoiding confusion and delay, S. =131= (3). 2. A change in the direction of the line of march is effected by giving a fresh point or points to move on. 3. When once a firing-line has been formed, a change of direction under fire will be effected either as described in S. =48=, or by forming a new firing-line in the required direction from the troops in rear, the old firing-line being withdrawn. 4. Undue rapidity tends to exhaust the men, and thus impair the accuracy of their fire. During the earlier stages of the attack, the ordinary pace should, therefore, be maintained. 5. When the defender’s fire begins to tell seriously the advance must be continued according to circumstances as laid down in S. =136= (3). =149.= _Machine Guns._ 1. The effective use of a machine gun depends on the promptitude of its commander in utilising opportunities which are, as a rule, very brief.