The difficulties of a retreat are naturally greater or less according as the battle has been fought under more or less favourable circumstances, and according as it has been more or less obstinately contested. The battle of Jena and La Belle-Alliance show how impossible anything like a regular retreat may become, if the last man is used up against a powerful enemy. Now and again it has been suggested(*) to divide for the purpose of retreating, therefore to retreat in separate divisions or even eccentrically. Such a separation as is made merely for convenience, and along with which concentrated action continues possible and is kept in view, is not what we now refer to; any other kind is extremely dangerous, contrary to the nature of the thing, and therefore a great error. Every lost battle is a principle of weakness and disorganisation; and the first and immediate desideratum is to concentrate, and in concentration to recover order, courage, and confidence. The idea of harassing the enemy by separate corps on both flanks at the moment when he is following up his victory, is a perfect anomaly; a faint-hearted pedant might be overawed by his enemy in that manner, and for such a case it may answer; but where we are not sure of this failing in our opponent it is better let alone. If the strategic relations after a battle require that we should cover ourselves right and left by detachments, so much must be done, as from circumstances is unavoidable, but this fractioning must always be regarded as an evil, and we are seldom in a state to commence it the day after the battle itself. (*) Allusion is here made to the works of Lloyd Bülow and others. If Frederick the Great after the battle of Kollin,(*) and the raising of the siege of Prague retreated in three columns that was done not out of choice, but because the position of his forces, and the necessity of covering Saxony, left him no alternative, Buonaparte after the battle of Brienne,(**) sent Marmont back to the Aube, whilst he himself passed the Seine, and turned towards Troyes; but that this did not end in disaster, was solely owing to the circumstance that the Allies, instead of pursuing divided their forces in like manner, turning with the one part (Blücher) towards the Marne, while with the other (Schwartzenberg), from fear of being too weak, they advanced with exaggerated caution. (*) June 19, 1757. (**) January 30, 1814. CHAPTER XIV. Night Fighting The manner of conducting a combat at night, and what concerns the details of its course, is a tactical subject; we only examine it here so far as in its totality it appears as a special strategic means.