Within these limits the arrangements made for reconnaissance should not require fresh dispositions, but merely supplementing as they gradually develop from strategical into tactical measures. This is a matter for consideration when detailing close patrols, as the tendency is to be too prodigal of the scanty force at disposal. When the army cavalry concentrates towards the flank of the army, the detachments of it which have been carrying out the reconnaissance against the enemy's front must be gradually relieved by the divisional cavalry. The army cavalry will only be able to assist the divisional cavalry in the close reconnaissance by the action of those portions of it which may fall back behind the front of their own army. In such a case all should be placed under a single command, to prevent useless expenditure of force and contradictory orders. Whether the divisional cavalry is to be reinforced by the army cavalry or _vice versâ_, or whether a separate sphere of action is to be assigned to each, must depend on circumstances. It will, however, seldom happen that the army cavalry will fall back behind the front of its own army. It will nearly always be most advantageously placed on the flank of the army, and will therefore only have to carry out such reconnaissance as is possible from this position. Such reconnaissance, however, is generally the most important. As already indicated, the reconnoitring squadrons will gradually fall back upon the army cavalry itself, or upon the advancing columns of the main army which will now be approaching them. The reconnoitring squadrons on the outer flank will, however, be well advised not to join themselves at once to the main body of the cavalry. They must rather seek to operate against the rear of the enemy, who is already deployed, or against his lines of advance, in order to be able to report the presence of any approaching hostile reserves as early as possible. As a single example of this, had the French at Mars la Tour acted in this manner they would very soon have discovered the approach of Wedel's Brigade and its approximate strength. They would not then have been surprised by the attack of this brigade nor would they have mistaken it for the advance-guard of the Third Army. One may well assume that after dealing with Wedel's Brigade the French would, under such circumstances, have proceeded to undertake a general offensive, and that the fortunes of the day might have been with them. The close reconnaissance before the decisive battle must seek, above all things, to obtain an idea of the grouping of the hostile forces. Herein lie the conditions of success or failure. To this end endeavours must be made to get far round the front of the enemy and to observe as many lines of approach as possible. Rapid and distant patrol riding and the straining of every nerve must be demanded in such cases.