Course of Tactics.-Field Fortification. depends entirely on the ground, the nature of which continually varies, and must accordingly regulate the dispositions of the lines and angles to be traced. This makes it obvious that all regular entrenchments, whose sides and angles are equal, cannot but be very defective where the ground is uneven. Nevertheless, there are some maxims, or general rules, which are usually reduced to eleven, viz. 1. The angles should neither be too acute, nor too obtuse, relatively to the lateral works, in order that, 2. Every line may be defended by the fire of another, within musket-shot. 3. If the ground be very uneven and irregular, the lines must be so disposed, that the slops, and even the bottom of every height, be entirely discovered. 4. However, if owing to great steepness, or to the ground being interrupted by numbers of small eminences, or cut with deep ravines, the above rule should become impracticable, then you must contrive, as much as lays in your power, to flank the parts consealed, with other lines. : 5. The flanks of the entrenchment should be well secured, that the enemy may not be able to turn them. 6. Those parts where an attack appears most practicable deserve and call for particular attention: every obstacle that can be thought of must be used to oppose the enemy; namely, chevaux-de-frise, palisades, trous-de-loup, abbatis, fougasses, &c. 7. When the ground is broken by heights, or vallies, salient angles must be made upon the former, and supplied with the artillery; and re-entering angles in the gorges, in the small vallies, in short, in those parts where two heights form a narrow bottom. 8. You must be careful to construct close redoubts at certain distances, so that in case the enemy should force any part of the entrenchment, yet they may not be able to resist the fire which takes them in flank, but presently be compelled to give up every advan tage they may have gained, and to retire. 9. If the ground be not chosen in such a manner that no part of the entrenchment, either in front, or on the flanks, may be com Course of Tactics.-Field Fortification. manded by any adjacent heights, the troops must never think of making the least movement with safety. 10. It is necessary to leave here and there openings of thirty or forty paces, that the troops may advance in front. These should never be made in salient, but always in re-entering angles, covered either with fleches or traverses, or closed up with chevaux-defrise. 11. If the roads in the rear of an entrenchment be not naturally good, they must be made so immediately in order to facilitate the retreat, if circumstances should require it. COURSE OF PRACTICAL ENGINEERING. PART I. MARCHES AND CAMPS. LECTURE SECOND. The order and conduct of the march of an army. 1. It results from what has already been said, that an exact. knowledge of a country is of the greatest importance in military. operations. Here it is almost indispensably necessary. It has been found by experience, that the march of an army must be made in columns; and, that it will be more or less expeditious and easy in proportion to their number; provided they do not cross each other. For that can never be done without some delay, and frequently not without disorder and confusion. When two columns meet, the fault is generally to be attributed to the inattention of the officer who has planned the march. It may be sometimes, however, unavoidable, but with a little care the inconveniences of such a meeting may be, in a great measure, removed. For example, let us suppose that two columns have to march, angular-wise, towards a point, where they must necessarily cross each other. In that case, the battalion which arrives first at the point of intersection must advance as quick as possible, and both columns will immediately halt; then the leading battalion of the other column will march forward: and thus they will advance alternately, each still keeping its own line of march, till the whole have crossed each other. By these means all confusion will be Course of Practical Engineering.-Lecture second. avoided, and the heads of the columns will remain in the same lines with respect to each other. A staff officer of rank ought also 'to be posted at the intersection of the roads, for the purpose of enforcing regularity and obedience to the orders. It may sometimes happen, that two roads are joined together, and separated again at the end of a few paces. In that case the columns can march by the side of each other, provided there is sufficient room. Or, if the nature of the country will admit of it, they can leave the road, and return to it at the most convenient place. For which purpose, conspicuous marks should be set up. Thus the order of march will not be changed; one column may keep upon the left, and the other column upon the right. I have never found any thing wanting to keep the line of march, but vigilance, activity, and the exercise of common sense. : 2. Two columns of the French army, in the seven years' war, had once the good fortune to cross each other upon the march, without the least delay or inconvenience, by means of the following expedient: the dryness of the season enabled one of them to march along the bed of a river, while the other was passing over the bridge. This circumstance excites the supposition that a bridge might be occasionally thrown over a hollow way with equal utility. And if the road should not be of sufficient depth to allow the loaded waggons a free passage, it would only be necessary that a little earth should be taken from the bottom, and thrown upon that part of the banks where the bridge is intended to be made. 3. In general the number of columns will be regulated by the nature of the country and the roads. The best and shortest roads are given to the heavy artillery and baggage waggons, and the longest to the cavalry; except when there may be particular reasons to the contrary. 4. When the enemy is to be attacked, the commander-in-chief of the army regulates the orders of march and of battle. This, therefore, does not belong to the engineer. 5. If there be no particular reasous for obliging the columns to follow the roads, they will gain time by marching across the country; because they can then extend their front, and proceed in a more direct line to the place of their destination. Hollow ways, Course of Practical Engineering.-Lecture second. ravines, and villages, must be carefully avoided, especially when an enemy is near; because, in such situations, the commanding officer will be under the necessity of contracting his front, and of course the march will be retarded; in the next place, because dis order will be unavoidable if he should then be attacked; and lastly, because every village will give a favourable opportunity for desertion. 6. When an enemy be near, the march must either be covered by a corps of light troops, or the whole army must march in order of battle; the encampment cannot be marked out till the troops arrive upon the ground; and the place will be frequently chosen by accident or necessity. 7. If the roads, defiles, &c. have not been previously repaired, the engineers must go forward with the pioneers some hours, or, if possible, the day before the march of the army, that they may be put into as good a state as time and circumstances will allow. Or, if there should be no pioneers, they must take some carpenters with them, and a sufficient number of peasants or soldiers, who will receive the necessary utensils from the park of artillery. 8. Before the engineers and their parties set out, they must make themselves acquainted with the height and breadth of the loaded baggage-waggons and artillery, as well the exact length of their axle-trees. For, if the columns are obliged to march through woods, all the branches or trees that are likely to be in their way must be cut down. They must widen all deep and narrow ruts, and, wherever it is necessary, they must slope off the sides of the hollow ways, except when they happen to be very hard or rocky. In that case they must raise their bottoms with stones, rubbish, or the stems of young trees laid crossways. 9. Every hole must be filled up with stones and gravel; or, if a sufficient quantity cannot be easily procured, strong fascines will answer the same purpose, provided they are laid across them, and sufficiently covered with earth. When an army is thus circumstanced, this is the most expedi tious, and indeed the only method of putting roads into temporary repair; and as such I mean it to be understood: for, if more durable repairs or new roads are necessary, other rules are to be at Course of Practical Engineering.-Lecture second. tended to, which will be hereafter explained; with the rules for the formation of bridges. 10. If there be ditches and morasses that have not been repaired, the artillery will be subjected to much delay, unless they are provided with some expedient, by which they may be enabled to pass them in security. Therefore, before they begin their march; I would recommend that a sufficient number of green trunks of trees should be collected, that a groove should be cut along the centre of each of them, and that their ends should be sloped off,* for the purpose of being conveniently joined together. If the park is large, as many of them should be taken as will load two or three waggons; and whenever the artillery may have occasion to cross a ditch, a swamp, or an old wooden bridge, two rows must be placed so as to allow the wheels to pass along the grooves. Such an expedition will always be of great service, especially when a forced march is to be made. I recommend green trunks of trees for such a purpose in preference to dry pieces of timber; because they can' be more expeditiously prepared, and are to be met with in alf places. 11. Instead of trusting too readily to a ford, which may have. been destroyed either by a late flood or the enemy, it is better that one or two bridges should be formed: because if it be afterwards found to be safe, one part of the column can pass through the river, while the other is marching over them; consequently much time will be gained. 12. Whenever a column is unexpectedly obliged to cross a brook or river (provided it is not too broad), the nearest trees will enable you to make a bridge. And a column of infantry will only. stand in need of a few rafters or planks, which are to be found in every village. It must be remembered, however, that those planks are to be laid double, and covered with turf; otherwise their elasticity and smoothness will be dangerous to the troops. But as it may sometimes happen, that there is no village within a considerable distance of the place, I shall proceed to explain the best methods of using trees on such occasions. Two, three, or four trunks of trees must be laid over the water at equal distances, and fixed with stakes to the ground; others of |