“The general of the sea has need of only one science, that of navigation. The one on land has need of all, or of a talent which is the equivalent of all, that will enable him to profit by all experience, and all knowledge. A general of the sea has nothing to divine. He knows where his enemy is, he knows his strength. A general on land never knows anything with certainty, never sees his enemy well, and never knows positively where he is.”