REPORT OF CAPT. GEORGE B. M°CLELLAN. 113 



these squadrons arrive abreast of the halted odd squadrons, and again advances when the odd 

 squadrons start the second time — for the distance between the lines is measured between the 

 nearest parts of the two ; if the 1st line retreats by alternate squadrons, commencing with the 

 odd squadrons, the 2d line stands fast until the even squadrons start, and moves with them. 



If the 1st line advances or retreats by echelons of divisions, the columns of attack of the 2d 

 line move at the same time as their corresponding divisions of the 1st line ; if but a jiart of the 

 1st line breaks by echelons, the other part remaining m line, the 2d line conforms to the movement. 



If the 1st line breaks by echelons on botli flanks, or by the centre, the 2d line moves in line, 

 with the rear echelons. If the 1st line breaks by echelons of squadrons, the divisions of the 2d 

 line conform to tlie movements of that squadron of their corresponding divisions of the 1st line 

 whicli is nearest them, and furthest from the enemy. 



CHANGES OF FRONT. 



The 1st line changes front as heretofore explained. 



When the front is changed 45°, the division of direction in the 2d line is the one corresponding 

 to that of the 1st line. The directing division of the 2d line, and all the others in rear of that 

 flank of the 1st line which forms forward, also form forward ; the division next to that of direction, 

 on the side in rear of that flank of the 1st line which forms to the rear, will have its new position 

 on the line of original formation of the 2d line, and at the point originally occupied by the nest 

 division on the other side of that of direction ; all the remaining divisions form to the rear. 



PI. 16, fig. 1, shows the manner of changing front forward 45°, on the first division of the 

 second regiment of the 1st line, and explains what has just been said, i. e., the first division of 

 the second regiment of the 2d line is that of direction, it and all the divisions of the 1st regiment 

 form forward, the second division of the second regiment occupies the original position of the 

 third division of the first regiment, and the third division of the second regiment forms to the rear. 



PI. 16, fig. 2, shows the manner of changing front 90°. This example will explain the general 

 rule for changing front 90°, which is as follows : in the second line, the division of direction is 

 the one corresponding to that of the 1st line ; it, and all the others behind that flank of the 1st 

 line which forms forward, form forward ; the two next divisions in rear of the other flank of the 

 1st line also form forward ; the remaining divisions of the 2d line form to the rear. 



PASSAGE OF THE LINE. 



This may be executed in three ways ; (a) by the 2d line advancing through the 1st ; (6) by 

 the 1st line retreating through the 2d ; (c) by the simultaneous movement of both lines in oppo- 

 site directions, i. e., the 1st line retreating, the 2d advancing. 



When the general commanding intends the 2d line to advance through the 1st, he sends 

 orders to the commander of the 2d line to advance ; if he intends the 1st line to retreat through 

 the 2d, he informs the commander of the latter of his intention, and orders the 1st line to 

 retreat. 



In the passage of the line, both may be formed in columns of attack, or. one in this order and 

 the other deployed. 



It is a general rule that any party of troops meeting, or passing, another party, leaves the 

 latter on its left ; therefore, if the 2d line, formed in columns of attack, is ordered to pass 

 through the 1st line, formed in like manner, the columns of the 2d line pass to the right of the 

 corresponding columns of the 1st line, as shown in plate 15, figure 9. 



If, under similar circumstances, the 1st line retreats through the 2d, the same principle is 



conformed to. 



15 O 



