CHAPTER XXVI.
HALLECK ASSUMES COMMAND IN THE FIELD--THE ADVANCE UPON CORINTH -- OCCUPATION OF CORINTH--THE ARMY SEPARATED.
General Halleck arrived at Pittsburg landing on the 11th of April and immediately assumed command in the field.

On the 21st General Pope arrived with an army 30,000 strong, fresh from the capture of Island Number Ten in the Mississippi River.

He went into camp at Hamburg landing five miles above Pittsburg.

Halleck had now three armies: the Army of the Ohio, Buell commanding; the Army of the Mississippi, Pope commanding; and the Army of the Tennessee.

His orders divided the combined force into the right wing, reserve, centre and left wing.
Major-General George H.Thomas, who had been in Buell's army, was transferred with his division to the Army of the Tennessee and given command of the right wing, composed of all of that army except McClernand's and Lew.