The first qualification in a general-in-chief is a cool head--that
is, a head which receives just impressions, and estimates things and
objects at their real value. He must not allow himself to be elated by
good news, or depressed by bad.
The impressions he receives either successively or simultaneously in
the course of the day, should be so classed as to take up only the
exact place in his mind which they deserve to occupy; since it is upon
a just comparison and consideration of the weight due to different
impressions, that the power of reasoning and of right judgment depends.
Some men are so physically and morally constituted as to see everything
through a highly-colored medium. They raise up a picture in the mind on
every slight occasion, and give to every trivial occurrence a dramatic
interest. But whatever knowledge, or talent, or courage, or other good
qualities such men may possess, nature has not formed them for the
command of armies, or the direction of great military operations.