ooga on the southwest is two hundred and
forty-two miles, which measures the length of that part of the
Holston and Tennessee valley known as East Tennessee. If Rosecrans
were at Rome, as General Crittenden's dispatch indicated, he was
more than a hundred and seventy miles distant from Knoxville, and
nearly three hundred miles from the region about Greeneville and the
Watauga River, whose crossing would be the natural frontier of the
upper valley, if Burnside should not be able to extend his
occupation quite to the Virginia line. It will be seen therefore
that the progress of the campaign had necessarily made Rosecrans's
and Burnside's lines of operation widely divergent, and they were
far beyond supporting distance of each other, since there was no
railway communication between them, and could not be for a long
time. Burnside captured some locomotives and cars at Knoxville; but
bridges had been destroyed to such an extent that these were of
little use to him, for the road could be operated but a short
distance in either direction and the amount of rolling stock was, at
most, very little. Complete success for Rosecrans, with the
reopening and repair of the whole line from Nashville through
Chattanooga, including the rebuilding of the great bridge at London,
were the essential conditions of further co-operation between the
two armies, and of the permanent existence of Burnside's in East
Tennessee.

Efforts had been made to extend the lines of telegraph as Burnside
advanced, [Footnote: Official Records, vol. xxx. pt. ii. p. 574; pt.
iii. p. 717.] but it took some time to do this, and even when the
wires were up there occurred a difficulty in making the electric
circuit, so that through all the critical part of the Chickamauga
campaign, Burnside had to communicate by means of so long a line of
couriers that three days was the actual time of transmittal of
dispatches between himself and Washington. [Footnote: _Id_., pt.
iii. p. 718.] The news from Rosecrans on the 10th was so reassuring
that Burnside's plain duty was to apply himself to clearing the
upper valley of the enemy, and then to further the great object of
his expedition by giving the loyal inhabitants the means of
self-government, and encouraging them to organize and arm themselves
with the weapons which his wagon trains were already bringing from
Kentucky. He had also to provide for his supplies, and must use the
good weather of the early autumn to the utmost,