If the army be of incongruous materials, generally a change of direction will be less advantageous than to entirely abandon the line, and save as many as possible of the troops for some new plan of operations.

(Maxim 20.) If, however, the undisciplined army be sustained by fortifications, it can take up the _accidental line of operations_ in the same manner, and with the same probability of success, as is done by a regular force.
We have examples of accidental lines in the operations of the king of Prussia, after the battle of Hohenkirchen, and of Washington, in New-Jersey, after the action of Princeton.

This is one of the finest in military history.

Napoleon had projected a change in his line of operations, in case he lost the battle of Austerlitz; but victory rendered its execution unnecessary.

Again in 1814 he had planned an entire change of operations; but the want of co-operation of the forces under Mortier and Marmont forced him to abandon a plan which, if properly executed, had probably defeated the allies.