army should occupy space enough to enable it to subsist
readily, and it should also keep as much concentrated as possible, to be
ready for the enemy should he show himself; and these two conditions are
by no means easily reconciled. There is no better arrangement than to
place the divisions of the army in a space nearly a square, so that in
case of need the whole may be assembled at any point where the enemy may
present himself. Nine divisions placed in this way, a half-day's march
from each other, may in twelve hours assemble on the center. The same
rules are to be observed in these cases as were laid down for winter
quarters.

ARTICLE XL.

Descents.

These are operations of rare occurrence, and may be classed as among the
most difficult in war when effected in presence of a well-prepared
enemy.

Since the invention of gunpowder and the changes effected by it in
navies, transports are so helpless in presence of the monstrous
three-deckers of the present day, armed as they are with a hundred
cannon, that an army can make a descent only with the assistance of a
numerous fleet of ships of war which can command the sea, at least until
the debarkation of the army takes place.

Before the invention of gunpowder, the transports were also the ships of
war; they were moved along at pleasure by using oars, were light, and
could skirt along the coasts; their number was in proportion to the
number of troops to be embarked; and, aside from the danger of tempests,
the operations of a fleet could be arranged with almost as much
certainty as those of an army on land. Ancient history, for these
reasons, gives us examples of more extensive debarkations than modern
times.

Who does not recall to mind the immense forces transported by the
Persians upon the Black Sea, the Bosporus, and the Archipelago,--the
innumerable hosts landed in Greece by Xerxes and Darius,--the great
expeditions of the Carthaginians and Romans to Spain and Sicily, that of
Alexander into Asia Minor, those of Caesar to England and Africa, that
of Germanicus to the mouths of the Elbe,--the Crusades,--the expeditions
of the Northmen to England, to France, and even to Italy?

Since the invention of cannon, the too celebrated Armada of Philip II.
was the only enterprise of this kind of any magnitude until that set on
foot by Napoleon against England in 1803. All other marine expeditions
were of no great extent: as, for example, those of Charles V. and of