as finally begun, rather by accident
than design, and on that day and the twentieth was fought the battle of
Chickamauga, one of the severest encounters of the whole war. Developing
itself without clear knowledge on either side, it became a moving
conflict, Bragg constantly extending his attack toward his right, and
Rosecrans meeting the onset with prompt shifting toward his left.

In this changing contest Rosecrans's army underwent an alarming crisis
on the second day of the battle. A mistake or miscarriage of orders
opened a gap of two brigades in his line, which the enemy quickly found,
and through which the Confederate battalions rushed with an energy that
swept away the whole Union right in a disorderly retreat. Rosecrans
himself was caught in the panic, and, believing the day irretrievably
lost, hastened back to Chattanooga to report the disaster and collect
what he might of his flying army. The hopeless prospect, however, soon
changed. General Thomas, second in command, and originally in charge of
the center, had been sent by Rosecrans to the extreme left, and had,
while the right was giving way, successfully repulsed the enemy in his
front. He had been so fortunate as to secure a strong position on the
head of a ridge, around which he gathered such remnants of the beaten
detachments as he could collect, amounting to about half the Union army,
and here, from two o'clock in the afternoon until dark, he held his
semicircular line against repeated assaults of the enemy, with a heroic
valor that earned him the sobriquet of "The Rock of Chickamauga." At
night, Thomas retired, under orders, to Rossville, half way to
Chattanooga.

The President was of course greatly disappointed when Rosecrans
telegraphed that he had met a serious disaster, but this disappointment
was mitigated by the quickly following news of the magnificent defense
and the successful stand made by General Thomas at the close of the
battle. Mr. Lincoln immediately wrote in a note to Halleck:

"I think it very important for General Rosecrans to hold his position at
or about Chattanooga, because, if held, from that place to Cleveland,
both inclusive, it keeps all Tennessee clear of the enemy, and also
breaks one of his most important railroad lines.... If he can only
maintain this position, without more, this rebellion can only eke out a
short and feeble existence, as an animal sometimes may with a thorn in
its vitals."

And to Rosecrans he telegraph