In 1805, Napoleon, while master of Vienna, detached the corps of
Bernadotte to Iglau to overawe Bohemia and paralyze the Archduke
Ferdinand, who was assembling an army in that territory; in another
direction he sent Davoust to Presburg to show himself in Hungary; but he
withdrew them to Brunn, to take part in the event which was to decide
the issue of the campaign, and a great and decisive victory was the
result of his wise maneuvers. Operations of this kind, so far from being
in opposition to the principles of the art of war, are necessary to
facilitate their application.

It readily appears from what goes before that precise rules cannot be
laid down for these operations, so varied in character, the success of
which depends on so many minute details. Generals should run the risk of
making detachments only after careful consideration and observation of
all the surrounding circumstances. The only reasonable rules on the
subject are these: send out as few detachments as possible, and recall
thorn immediately when their duty is performed. The inconveniences
necessarily attending them may be made as few as practicable, by giving
judicious and carefully-prepared instructions to their commanders:
herein lies the great talent of a good chief of staff.

One of the means of avoiding the disastrous results to which detachments
sometimes lead is to neglect none of the precautions prescribed by
tactics for increasing the strength of any force by posting it in good
positions; but it is generally imprudent to engage in a serious conflict
with too large a body of troops. In such cases ease and rapidity of
motion will be most likely to insure safety. It seldom happens that it
is right for a detachment to resolve to conquer or die in the position
it has taken, whether voluntarily or by order.