Respecting the length of a march and the time it requires, it is natural for us to depend on the general results of experience.
For our modern armies it has long been settled that a march of three miles should be the usual day’s work which, on long distances, may be set down as an average distance of two miles per day, allowing for the necessary rest days, to make such repairs of all kinds as may be required.
Such a march in a level country, and on tolerable roads will occupy a division of 8,000 men from eight to ten hours; in a hilly country from ten to twelve hours. If several divisions are united in one column, the march will occupy a couple of hours longer, without taking into account the intervals which must elapse between the departure of the first and succeeding divisions.
We see, therefore, that the day is pretty well occupied with such a march; that the fatigue endured by a soldier loaded with his pack for ten or twelve hours is not to be judged of by that of an ordinary journey of three miles on foot which a person, on tolerable roads, might easily get over in five hours.
The longest marches to be found in exceptional instances are of five, or at most six miles a day; for a continuance four.
A march of five miles requires a halt for several hours; and a division of 8,000 men will not do it, even on a good road, in less than sixteen hours. If the march is one of six miles, and that there are several divisions in the column, we may reckon upon at least twenty hours.