It is above all in mountainous countries, and in those interspersed
with woods and marshes, that it is of importance to observe this maxim;
for, the convoys and means of transport being frequently embarrassed
in defiles, an enemy by manœuvring may easily disperse the escorts, or
make even a successful attack upon the whole army, when it is obliged,
from the nature of the country, to march in an extended column.