The arrangement of marches, and the choice of positions depend in this case also upon so many other things, especially on the supply of the Army, on strong natural obstacles in the country, on large towns, &c. &c., that it would be ridiculous pedantry to attempt to show by a geometrical analysis how the pursuer, being able to impose his laws on the retreating enemy, can compel him to march at night while he takes his rest. But nevertheless it is true and practicable that marches in pursuit may be so planned as to have this tendency, and that the efficacy of the pursuit is very much enchanced thereby. If this is seldom attended to in the execution, it is because such a procedure is more difficult for the pursuing Army, than a regular adherence to ordinary marches in the daytime. To start in good time in the morning, to encamp at mid-day, to occupy the rest of the day in providing for the ordinary wants of the Army, and to use the night for repose, is a much more convenient method than to regulate one’s movements exactly according to those of the enemy, therefore to determine nothing till the last moment, to start on the march, sometimes in the morning, sometimes in the evening, to be always for several hours in the presence of the enemy, and exchanging cannon shots with him, and keeping up skirmishing fire, to plan manœuvres to turn him, in short, to make the whole outlay of tactical means which such a course renders necessary. All that naturally bears with a heavy weight on the pursuing Army, and in War, where there are so many burdens to be borne, men are always inclined to strip off those which do not seem absolutely necessary. These observations are true, whether applied to a whole Army or as in the more usual case, to a strong advance-guard. For the reasons just mentioned, this second method of pursuit, this continued pressing of the enemy pursued is rather a rare occurrence; even Buonaparte in his Russian campaign, 1812, practised it but little, for the reasons here apparent, that the difficulties and hardships of this campaign, already threatened his Army with destruction before it could reach its object; on the other hand, the French in their other campaigns have distinguished themselves by their energy in this point also. Lastly, the third and most effectual form of pursuit is, the parallel march to the immediate object of the retreat. Every defeated Army will naturally have behind it, at a greater or less distance, some point, the attainment of which is the first purpose in view, whether it be that failing in this its further retreat might be compromised, as in the case of a defile, or that it is important for the point itself to reach it before the enemy, as in the case of a great city, magazines, &c., or, lastly, that the Army at this point will gain new powers of defence, such as a strong position, or junction with other corps.