HEADQUARTERS, Huntsville, July 13, 1862.

General HALLECK:

General Boyle reports that Morgan's force is increasing by the rising of secessionists in the counties on the Ohio; that he is now at Danville and Harrodsburg, and will have Lexington and Frankfort if troops are not sent immediately. I shall have to send troops there. This morning I received a dispatch from Nashville saying that 3,000 cavalry surprised and, as the phrase is, "cut to pieces" the force at Murfreesborough, two regiments of infantry, a battery, and some cavalry. I have no particulars and no information since. There has no doubt been an attack threatening Nashville and our railroad communications. I have ordered troops to meet the danger. The road to Stevenson was finished a strong force on the roads, but the lines are long and exposed from the east. Everything indicates that the enemy is throwing a heavy cavalry force into Kentucky and Middle Tennessee, which will give us occupation. The force at Chattanooga is stated at from 15,000 to 20,000, exclusive of the force under Smith farther east.

D. C. BUELL.

NASHVILLE, July 13, 1862.

Major-General BUELL:

Lewis B. Parsons asks me if I can spare him more cars and engines for immediate use at Columbus. I have answered him Numbers I have sent four engines and forty cars. We will require more cars and about two more engines to work the road from Nashville to Huntsville via the two routes.

I have not received your answer to my former dispatch o this subject nor to the dispatch asking instructions as to disposition of my bridge force.

J. B. ANDERSON.

HEADQUARTERS, Huntsville, July 13, 1862.

J. B. ANDERSON, Nashville:

Have cars at Reynolds' Station immediately to carry four regiments, say 2,500 men, through to Nashville or Louisville, according to circumstances. If the road to Stevenson should be interrupted by the reported attack on Murfreesborough resume the other road for supplies promptly.

D. C. BUELL.

NASHVILLE, July 13, 1862.

General D. C. BUELL:

I have not received any dispatch from you in relation to trains at Reynolds', but will send out all the cars I have just so soon as I can get the engines fired and trains made up. It will be important to increase the guards at the bridges, and especially at Duck River and Franklin.

Will 8 a.m. be soon enough to reach Reynolds' with trains?

J. B. ANDERSON.