road, the interval between the
departure of the several corps is sufficiently great when the artillery
may readily file off. Instead of separating the corps by a whole march,
the army would be better divided into two masses and a rear-guard, a
half-march from each other. These masses, moving off in succession with
an interval of two hours between the departure of their several
army-corps, may file off without incumbering the road, at least in
ordinary countries. In crossing the Saint-Bernard or the Balkan, other
calculations would doubtless be necessary.

I apply this idea to an army of one hundred and twenty thousand or one
hundred and fifty thousand men, having a rear-guard of twenty thousand
or twenty-five thousand men distant about a half-march in rear. The army
may be divided into two masses of about sixty thousand men each,
encamped at a distance of three or four leagues from each other. Each of
these masses will be subdivided into two or three corps, which may
either move successively along the road or form in two lines across the
road. In either case, if one corps of thirty thousand men moves at five
A.M. and the other at seven, there will be no danger of interference
with each other, unless something unusual should happen; for the second
mass being at the same hours of the day about four leagues behind the
first, they can never be occupying the same part of the road at the same
time.

When there are practicable roads in the neighborhood, suitable at least
for infantry and cavalry, the intervals may be diminished. It is
scarcely necessary to add that such an order of march can only be used
when provisions are plentiful; and the third method is usually the best,
because the army is then marching in battle-order. In long days and in
hot countries the best times for marching are the night and the early
part of the day. It is one of the most difficult problems of logistics
to make suitable arrangements of hours of departures and halts for
armies; and this is particularly the case in retreats.

Many generals neglect to arrange the manner and times of halts, and
great disorder on the march is the consequence, as each brigade or
division takes the responsibility of halting whenever the soldiers are a
little tired and find it agreeable to bivouac. The larger the army and
the more compactly it marches, the more important does it become to
arrange well the hours of departures and halts, especially if the army
is to mo