27.) When you are driven from your first position, the rallying point of your columns should be so far in the rear that the enemy cannot get there before them. It would be the greatest of disasters to have your columns attacked one by one before their reunion.

28.) No detachment should be made the day preceding a battle, for during the night the state of things may change, either by a retreat of the enemy or by the arrival of strong reinforcements, which would put him in condition to assume the offensive and render the premature dispositions which you have made ruinous.

29.) When you have it in contemplation to give battle, it is a general rule to collect all your strength and to leave none unemployed. One battalion sometimes decides the issue of the day.

30.) Nothing is more rash or more opposed to the principles of war than a flank march in presence of an army in position, especially when that army occupies heights at the foot of which you must defile.

31.) When you intend to engage in a decisive battle, avail yourself of all the chances of success; more especially if you have to do with a great captain; for if you are beaten, though you may be in the midst of your magazines and near your fortified posts, woe to the vanquished!

32.) The duty of an advance guard does not consist in advancing or retreating, but in maneuvering. It should be composed of light cavalry supported by a reserve of heavy, and by battalions of infantry, with artillery to support them. The advance guard should be formed of choice troops; and the generals, officers and soldiers, according to the requirements of their respective rank, should be thoroughly acquainted with the peculiar tactics necessary in this kind of service. An untrained company would be only a source of embarrassment.

33.) It is contrary to the usages of war to cause your parks or heavy artillery to enter a defile, the opposite extremity of which is not in your possession; since, in the event of a retreat, they will embarrass you and be lost. They ought to be left in position, under a suitable escort, until you have made yourself master of the termination of the defile.

34.) It should be adopted as a principle never to allow intervals through which the enemy can penetrate between the different corps forming the line of battle, unless you have laid a snare into which it is your object to draw him.

35.) The camps of the same army should be always so placed as to be able to sustain each other.

36.) When a hostile army is covered by a river on which it has several bridgeheads, you should not approach it in front, for in doing so your forces would be too little concentrated and in danger of being broken into detached parts, if the enemy should sally from one of the bridgeheads. You should approach the river you wish to cross in columns disposed in echelon, so that there may be only a single column the foremost one which the enemy can attack without exposing his own flank.

Meanwhile the light troops will line the bank; and when you have fixed on the point at which to pass, you must proceed rapidly to the spot and throw the bridge across. You must take care that the bridge shall always be at a distance from the leading echelon in order to deceive the enemy.

37.) The moment that you become master of a position which commands the opposite bank, you obtain many facilities for effecting the passage of a river, especially if that position has sufficient extent to admit of your planting a large number of pieces of artillery upon it. This advantage is less if the river is more than six hundred yards wide, as the grape no longer reaches the other shore; and consequently the troops that oppose the passage can, by suitable precautions, easily render your fire of little effect. Hence if the grenadiers charged with the duty of passing the river to protect the bridge, succeed in crossing to the other side, they will be swept off by the enemy's grapeshot; as his batteries established four hundred yards from the termination of the bridge are near enough to pour in a very destructive fire, although more than a thousand yards distant from the batteries of the army which is endeavouring to pass. Therefore he has all the advantage of the artillery. So in such a case a passage is not practicable unless you either contrive to take the enemy by surprise, or are protected by an intervening island, or avail your self of a deep re-entrant bend, which enables you to erect batteries crossing their fire just in advance of the point where a landing is to be effected. Such an island or re-entrant forms a natural bridgehead and gives the advantage of the artillery to the attacking army.

When a river is less than a hundred and twenty yards in breadth and you can command the opposite bank, the troops that are thrown over to the other side derive such advantages from the protection afforded by the artillery that, however slight the re-entrant formed by the river may be, it is impossible for the enemy to prevent the establishment of the bridge. Under such circumstances, the most skillful generals, when they have been able to foresee the designs of their antagonist and arrive with their army at the point at which he was making his attempt, have contented themselves with disputing the passage of the bridge. A bridge being in fact a defile, you should place yourself in a half-circle around its extremity and take measures to shelter yourself at the distance of six or eight hundred yards from the fire of the other bank.

38.) It is difficult to prevent an enemy provided with bridge equipage from crossing a river. When the object of the army which disputes the passage is to cover a siege, the commanding general, as soon as he is certain that he cannot successfully oppose the passage, should take measures to arrive in advance of the enemy at a position between the river and the place whose siege he is covering.

39.) In the campaign of 1645, the forces of Turenne were hemmed in before Philipsburgh by a very numerous army. There was no bridge over the Rhine, but Turenne established his camp on the ground lying between the river and the place. This should serve as a lesson to officers of the engineer department in regard to the construction of bridgeheads as well as of fortresses. There should be left, between the fortress and the river, a space in which an army may be rallied and formed; as the entrance of the troops into the place itself would endanger it. An army pursued and retiring upon Mayence, must necessarily be in a precarious situation, since it would require more than one day to pass the bridge, and the works surrounding Cassel are too small to contain an army without crowding and confusion. Four hundred yards should have been left between the works and the Rhine. It is essential that bridgeheads before large rivers should be constructed on this plan; otherwise they will be of little utility in protecting the passage of an army in retreat. Bridgeheads, as they are taught in the schools, are good only before small rivers where the defile is not long.

40.) Fortresses are useful in offensive as well as defensive war. Undoubtedly they cannot of themselves arrest the progress of an army, but they are excellent means of delaying, impeding, enfeebling and annoying a victorious enemy.

41.) There are only two modes of prosecuting a siege successfully. One is to begin by beating the hostile army employed to cover the place, driving it from the field of operations and forcing its remains beyond some natural obstacle, such as a chain of mountains or a large river. This first difficulty overcome, you must place an army of observation behind the natural obstacle until the labors of the siege are finished and the place is taken.

But if you wish to take the place in the face of an army of relief without hazarding a battle, you must be provided with siege equipage, ammunition and provisions for the time during which the siege is expected to continue; and must form lines of contravallation and circumvallation, turning, meanwhile, the peculiarities of the ground such as heights, woods, marshes and overflows to the best account.

As there is then no necessity for keeping up any communication with your depots, you have only to hold in check the army of relief To this end you should form an army of observation which must never lose sight of the enemy and which, while shutting him out from all access to the place, may always have time to fall upon his flanks or rear, if he should steal a march upon you. By taking advantage of your lines of contravallation you can employ a part of the besieging forces in giving battle to the army of relief.

A siege therefore, in the presence of a hostile army requires to be covered by lines of circumvallation.

If your army is so strong that, after leaving before the place a body four times the number of the garrison, it is still equal to the army of relief, it may move to a greater distance than one day's march.

If, after making the detachment, it remains inferior to the army of relief, it should be posted at one short day's march from the place besieged, so as to be at liberty to fall back on the lines or receive succor in the event of sustaining an attack.

If the two armies of siege and of observation, united, are equal only to the army of relief, the besieging army must remain altogether within or near its lines and employ itself in pushing the siege with all possible activity.

42.) Feuquieres has said that you should never wait for the enemy in your lines of circumvallation, but should go out and attack him. The maxim is erroneous. No rule of war is so absolute as to allow no exceptions, and waiting for the enemy in the lines of circumvallation ought not to be condemned as injudicious in all cases.

43.) They who proscribe lines of circumvallation and all the aid which the art of the engineer can furnish, gratuitously deprive themselves of auxiliaries that are never injurious, almost always useful and often indispensable. The principles of field fortification, however, need improvement. This important branch of the art of war has made no progress in modern times. It is even at this day in a lower state than it was two thousand years ago. Officers of the engineer department ought to be encouraged to perfect this branch of their art and raise it to a level with others.

44.) When you have a hospital and magazines in a fortified town, and circumstances are such as not to admit of your leaving a sufficient garrison to defend it, you should at least make every possible exertion to put the citadel in security from a coup de main.

45.) A fortified place can protect a garrison and arrest the enemy only a certain length of time. When that time has elapsed and the defences of the place are destroyed, the garrison may lay down their arms. All civilized nations have been of one opinion in this re- spect, and the only dispute has been as to the greater or less degree of resistance which the governor should offer before capitulating. Yet there are generals Villars is of the number--who hold that a governor ought never to surrender, but that in the last extremity he should blow up the fortifications and take advantage of the night to cut his way through the besieging army. In case you cannot blow up the fortifications, you can at any rate sally out with your garrison and save your men. Commanders who have pursued this course have rejoined their army with three-fourths of their garrison.

46.) The keys of a fortified place are ample compensation for permiffing the garrison to retire unmolested, whenever the latter evince a determination to die rather than accept less favorable terms. It is always better, therefore, to grant an honorable capitulation to a garrison which has resisted vigorously than to run the risk of an attempt to storm.

47.) The infantry, cavalry and artillery cannot dispense with each other. They ought not be quartered in such a manner as always to be able to support each other in case of surprise.

48.) Infantry formed in line should be in two ranks only, for the musket cannot otherwise be used with equal effect. It is admitted that the fire of the third rank is very imperfect and even injurious to that of the first two.

But though the great body of the infantry should be drawn up, as has just been said, in two ranks, the absence of a regular third rank should be supplied by supernumeraries composed of one soldier out of nine or one every two yards.

49.) The practice of mingling companies of horse and foot together is bad; it produces nothing but trouble. The cavalry is deprived of its capacity for rapidity of motion; it is cramped in all the movements; it loses its impulse.

The infantry, too, is exposed; for, at the first movement of the cavalry, it remains without support. The best mode of protecting cavalry is to suport its flank.

50.) Charges of cavalry are equally serviceable in the beginning, the middle and the end of a battle. They should be executed whenever they can be made on the flanks of the infantry, particularly when the latter is engaged in front.