The first and most important rule in offensive war is, to keep your
forces as much concentrated as possible. This will not only prevent
misfortune, but secure victory,--since, by its necessary operation, you
possess the power of throwing your whole force upon any exposed point of
your enemy's position.

To this general rule some writers have laid down the following
exceptions:--

1st. When the food and forage of the neighborhood in which you act have
been exhausted and destroyed, and your magazines are, from any cause,
unable to supply the deficiency, one of two things must be done; either
you must go to places where these articles abound, or you must draw from
them your supplies by _detachments_. The former is rarely compatible
with your plan, and necessarily retards its execution; and hence the
preference which is generally given to the latter.

2d. When reinforcements are about to join you, and this can only be
effected by a march through a country actually occupied by hostile
corps, or liable to be so occupied, you must again waive the general
rule, and risk one party for the security of the other; or, (which may
be better,) make such movements with your main body as shall accomplish
your object.

3d. When you have complete evidence of the actual, or probable
insurrection in your favor, of a town or province of your enemy, or of a
division of his army, you must support this inclination by strong
_detachments_, or by movements of your main body. Napoleon's operations
in Italy, in 1796-7, furnish examples of what is here meant.