Fig. 129.

S. 208. When two Lines change Pofition on a central point of the firft Line.

1. A. is the point on which the change is to be made; a. is obviously its correfponding point in the fecond line whofe diflance in paces is known.The direction of the first line AR, being afcertained, it becomes immediately neceffary to mark the correfponding point a, 2. in the fecond line, and also the point of interfection d, that the prolongation of that line may be alfo determined.-From the point A, therefore and in a direction perpendicular to the new line, a perfon accurately paces the known distance between the two lines, and halts at a, 2; and from thence obferves by his eye, the perpendicular to the line which he has juft paced, and also its interfection with the fecond line, which gives the platoon of point d, together with the direction of the new fecond line.The points a, 2. and d, being thus fixed, the lines proceed to make their movement, viz. the first line by the echellon march (S. 195); the fecond line B breaks inward to the platoon d; that platoon moves its pivot flank along the new line followed by all those betwixt it, and a, till a, arrives at the point a, 2.-The other platoons and battalions of the fecond line move relatively to the part a, d, the whole performing the precife operation already detailed in the change of pofition of the line on a movable central point S. 185.

2. But in order to accelerate the movement of the fecond line in central changes; a platoon or flank

point o, as much beyond a, as a, is removed from d, may be taken; this point is evidently the one, which will reft at the point of intersection d, when a, is arrived and halted at a, 2.--As foon therefore as Fig. 129. the points o, d, are ascertained and without waiting for the progreffive movement of this center part of the line, every thing that is in rear of o, may march and form in the new pofition, regarding o, 2, as its leading flank point, and every thing that fronts to d, regarding d, 2, as its leading flank point will march and form upon it, in the new line accordingly. S. 186.

3. In order the better to afcertain the parallel direction of the new fecond line, 2 perfons feparated from each other about 100 paces, may fet out from different points of the new first line, and accurately Fig. 129. pace the known diftance of the fecond; when they halt, the line of their prolongation gives the new direction, and also the interfection of the second lines.

Or if the first line points on any very diftant object the fecond line from the point a, 2, will be readily judged to pass a very little behind that object.

S. 209.

S. 209.

When two Lines change Pofition forward, on a flank of the first Line.

Fig. 130.

1

The direction of the first line being afcertained, that line will march into it by the echellon march, S. 195. In the mean time the correfponding flank point a, 2, in the new fecond line having been taken, and alfo the point d, in the interfection of the two lines; these points ferve as the bafe of formation.The second line will break into open column facing to the platoon d, of interfection; the whole will proceed as in S. 185. that platoon marching along the new line till a, arrives at a, 2: and when the other battalions which have moved forward are anew arranged in open column, they wheel up into line,

S. 210.

S. 210.

When two Lines change pofition back-
ward, on a flank of the firft Line.

The direction of the first line being afcertained, that line will march into it, by the echellon movement to the rear, S. 195.-The correfponding points a, 2, and d, in the new fecond line ferving as a base of formation, having been afcertained as well as the Fig. 131. point o, that line breaks into open column facing to the point of interfection: The part of the line between a, and o, marches on to the point of interfection, and from thence prolongs the new lines: The part of the line behind o, regarding d, as its leading flank point of formation, will march and form upon it, in the new line accordingly. S. 186.

S. 211.

Fig. 132.

S.211. When two formed Lines wheel into open Column, march to a Flank, change Direction, and take up a new Pofition.

1. If the new pofition is a retired one.-Both lines wheel into open column (fuppofe the left in front) and move on.-C. is a point where the head of the first line is to change its direction into that of C. D. by wheeling on its pivot flank: The leader of the fecond line being apprized of this point fends forward to ascertain his correfponding point c. and his parallel direction c. d.; these two points become the base of formation for the fecond line, and d. is in the interfection of the old and new lines.-Both columns proceed in their first direction, and when the first line arrives at C. the head wheels on its pivot into the direction C. D. followed by the reft of its column; but the fecond line then changing its head on the point c. moves towards it, there to enter its corre1ponding direction. The first line halts, and fuch parts of it as are in the new direction remain fo; while the rear of the column, by the movement of S. 182. gains the new direction, and by wheeling up forms in line; or, if the ground permits, it enters the new line by the echellon march of S. 158, each divifion first counter-marching by files, and then facing about, fo that its rear rank may lead.

2. When the first line halts, if the head divifion of the fecond line has not entered the new direction, it ftill moves on to its point of entry c. prolongs the