e had the advantage of position and (for the
first time against this particular antagonist) of nearness to his base
of supplies. Lee had been compelled to divide his army in order to get
it promptly into position on the north side of the Potomac. McClellan's
tardiness sacrificed Harper's Ferry (which, on September 15th, was
actually surrounded by Lee's advance) with the loss of twelve thousand
prisoners. Through an exceptional piece of good fortune, there came into
McClellan's hands a despatch showing the actual position of the
different divisions of Lee's army and giving evidence that the two wings
were so far separated that they could not be brought together within
twenty-four hours. The history now makes clear that for twenty-four
hours McClellan had the safety of Lee's army in his hands, but those
precious hours were spent by McClellan in "getting ready," that is to
say, in vacillating.

Finally, there came the trifling success at South Mountain and the drawn
battle of Antietam. Lee's army was permitted to recross the Potomac with
all its trains and even with the captured prisoners, and McClellan lay
waiting through the weeks for something to turn up.

A letter written by Lincoln on the 13th of October shows a wonderfully
accurate understanding of military conditions, and throws light also
upon the character and the methods of thought of the two men:

"Are you not overcautious when you assume that you cannot do what
the enemy is constantly doing? Should you not claim to be at least
his equal in prowess, and act upon the claim? As I understand, you
telegraphed General Halleck that you cannot subsist your army at
Winchester unless the railroad from Harper's Ferry to that point be
put in working order. But the enemy does now subsist his army at
Winchester, at a distance nearly twice as great as you would have to
do, without the railroad last named. He now waggons from Culpeper
Court House, which is just about twice as far as you would have to
do from Harper's Ferry. He is certainly not more than half as well
provided with waggons as you are.... Again, one of the standard
maxims of war, as you know, is to 'operate upon the enemy's
communications without exposing your own.' You seem to act as if
this applies against you, but cannot apply it in your favour. Change
positions with the enemy, and think you not he would break your
communication with Richmond in