If the army should be divided, and march in different columns by indirect roads, a rendezvous or place d’armes must be marked out in writing, where the whole may conveniently meet on the line of march. The utmost attention must be paid to the selection of this spot, by the adjutant and quarter-master general, lest it should be exposed to a surprise from the enemy; on which account it is kept as secret as possible, lest any intelligence should be given to him by deserters or spies. The hour and the manner in which the several columns are to arrive, is specifically stated to the different leaders; and scouts, &c. are sent round the country to discover the enemy’s movements.
If there should be any reason to apprehend an attack, the various precautions must be increased in proportion to the alarm.
An army must always march, if it possibly can, in that order from which it may easily and expeditiously deploy into line; that is, it should invariably preserve the order of battle; every column bearing a natural front towards the enemy. Montecuculli further adds, that an army must invariably march the right or left in front, and not from its centre.
Field-pieces, with a sufficient quantity of ammunition, shovels, spades, and pick-axes always at hand, must be disposed along the most vulnerable part of the rendezvous; these must be guarded by a body of cavalry and infantry, who are to be selected for that specific duty.
Care is likewise taken to lodge the baggage-waggons, &c. in the most secure and best defended spot.
The two first lines of the army will consist of the mounted artillery in front, next to which will stand the different squadrons of horse that are posted in intervals between the infantry battalions: after these will follow the train of caissons, &c. in as many files as the road will admit; then the stores and baggage, and finally the reserve.
Whenever the leading columns have passed an obstacle, the front man must be halted till the rear have completely cleared it likewise; and when the whole enters an open country, the line must be formed, and the march be continued in order of battle until a fresh obstacle occurs, when the troops must be prepared to pass the defile, the advanced guard leading, the main body following next, and the reserve bringing up the rear.
When an army is thus advancing, the right or left flank (according to circumstances) of its line of march, must be covered by rivers, and banks, rising grounds, or eminences; and if these natural advantages do not present themselves, artificial ones must be resorted to. These may consist of waggons, chevaux de friezes or other temporary means of defence; the quantity, &c. must depend upon the nature of the country, and the number of troops that compose the columns.
It is, however, impossible to set down general rules for all cases; these must vary with the manifold circumstances that occur, and the different designs which are to be accomplished or pursued.
When the movements of an army are to be concealed, the march must be undertaken at night through woods, vallies, and concealed ways; all frequented and inhabited places must be carefully avoided; no loud instruments must on any account be played; and if fires are made, they must only be lighted on the eve of breaking up camp; in which case they must be left burning, for the purpose of deluding the enemy into a supposition, that the troops have not moved.