1862 Army Officer's Pocket Companion - A Manual for Staff Officers in the Field
Article 42 (pg. 91)
Marches executed to Assemble Armies
To assemble armies, route marches are executed. Generally these are made by battalions, distant on day's march from each other; the cavalry the most of the time proceeding by the side roads, usually the less direct, but it is difficult to make a numerous cavalry corps march together during a whle campaign without interfering with the rapidity of its own movements, and without great difficulty of subsisting it, this corps should not exceed 6,000 horses. The artillery follows the cavalry, or if it has a very long train, it may proceed by itself on a separate road.
The troops begin their concentration on the base of operations: when operations are beginning, the successive bodies draw towards each other, and the army encamps in lines a day's march from each other; upon getting near the enemy, columns are formed; especially if the country presents parallel roads of debouche. It is always advantageous to march a corps de armee by several roads, its divisions at distances apart suitable for deployment, and in order of battle; but if therer is but one communication, distance of 200 yards should be left between the different arms, and the cavalry more in the rear of the column.
In these marches, when a defile is to be passed, the order in which the troops shall successively pass, should be arranged beforehand, and made known. The general rule is never pile up the troops in such a manner that their movements shall be difficult, and their action paralized; but they must be kept sufficiently near, so that the enmeny may not by a rapid movement fall upon isolated bodies and beat in detail.
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...too short as well as too long marches are to be avoided. A mean average of 20 miles is the proper measure to adopt, remembering that cavalry can, from time to timme, clear as much as 30 miles, and that infantry ought never to march less than 15 miles. For both infantry and cavalry one day of rest is sufficient after six or eight days of consecutive marching. It is of importance, when far from the enemy, not to regulate the march of cavarly by that of the infantry, for it would be prematurely injuring the former. The departure should take place neither too early nor too late. One hour between reville and the assembling of troops will enable every one to make easily all the preparations for departure. The men eat their soup and keep the meat for the halt. The horses take a feed of oats. A guide, either civilian or military, will acquainted with all the prticulars of the road, accompanies the commander of the troops if he is not himself familiar with them.
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Note: Unfortunately, due to the hour and the realities of life--I cannot type further, word for word from the manual. However, it might be on line to be viewed there:
Marches by Infantry goes approximately 45 minutes, covering 2 1/2 miles. Stop 5 minutes for every mile marched, repeating such. Thirty minutes for lunch. Time start 6 a.m., due time at destination 2 p.m. for a 20 mile march.
M.E. Wolf