If a bad road or a hilly country has to be marched over, all these calculations as to time and distance undergo such modifications that it is difficult to estimate, with any certainty, in any particular case, the time required for a march; much less, then, can any general theory be established. All that theory can do is to direct attention to the liability to error with which we are here beset. To avoid it the most careful calculation is necessary, and a large margin for unforeseen delays. The influence of weather and condition of the troops also come into consideration. Since the doing away with tents and the introduction of the system of subsisting troops by compulsory demands for provisions on the spot, the baggage of an army has been very sensibly diminished, and as a natural and most important consequence we look first for an acceleration in the movements of an army, and, therefore, of course, an increase in the length of the day’s march. This, however, is only realized under certain circumstances. Marches within the theatre of war have been very little accelerated by this means, for it is well known that for many years whenever the object required marches of unusual length it has always been the practice to leave the baggage behind or send it on beforehand, and, generally, to keep it separate from the troops during the continuance of such movements, and it had in general no influence on the movement, because as soon as it was out of the way, and ceased to be a direct impediment, no further trouble was taken about it, whatever damage it might suffer in that way. Marches, therefore, took place in the Seven Years’ War, which even now cannot be surpassed; as an instance we cite Lascy’s march in 1760, when he had to support the diversion of the Russians on Berlin, on that occasion he got over the road from Schweidnitz to Berlin through Lusatia, a distance of 225 miles, in ten days, averaging, therefore, twenty-two miles a day, which, for a Corps of 15,000, would be an extraordinary march even in these days.