STRENGTH.--Work in the Outpost Line is most exhausting. Not a man or a horse should be employed there if their services can be dispensed with, and although the number of troops allotted for the work depends almost entirely upon the nature of the country and the tactical situation, it is laid down in the text-books that if an unnecessarily large proportion of the whole force is so employed the force will suffer in efficiency. It can also be seen that although the work is of the first importance and fraught with the greatest difficulties, it is clearly possible for a comparatively small body of troops to carry it out. Observation requires intelligence and vigilance rather than numbers; Resistance can be provided by the Delaying Action on a wide front of small numbers of skilled troops with the relative advantage conferred upon them in defence by machine guns and small arms, and with the assurance of support from their Main Body close at hand. OBSERVATION.--A force can only be regarded as secure from surprise when every body of the enemy within striking distance is so closely watched that it can make no movement by night or day without its becoming known immediately to the observers of the Outposts. By day the Outpost commander will carry out Reconnaissance some distance ahead of his position by means of Aircraft and Patrols of mounted troops and cyclists, while the commander of each Outpost company keeps the approaches to the position under observation by sentries, so posted as to see and hear unobserved by a hostile force. By night, the Aircraft and mounted troops are unable to render much assistance as moving patrols, and the work of Reconnaissance and Observation falls upon the platoons of the Outpost companies. {131}