merce, opposite Big Island, a combined attack by the troops at Ironton and Cape Girardeau has been determined upon the destroy them. Brigadier-General Prentiss has therefore been directed to move with all his disposable force to Dallas. From that place he will proceed towards Cape Girardeau, first attacking and destroying the rebels at Jackson, should he ascertain that any are stationed at that place. Colonel Smith, now in command at Cape Girardeau, has been instructed to put himself in communication with General Prentiss at Dallas, and unite the forces at or near Jackson. Upon this junction being effected, General Prentiss has been ordered to send information to that effect to Colonel Wallace, commanding at Bird's Point, who will thereupon move with two regiments to Charleston, and after occupying that place make reconnaissance along the railroad, and advance as far as possible.

Colonel Waagner, chief of artillery at Cairo, left Saint Louis last night, with the regiment of Colonel Pugh, by steamboat, for Bird's Point, to exchange that regiment there with Colonel McArthur's, and to undertake an expedition with two gunboats, under Commander Rodgers, to Belmont, to destroy the fortifications erecting by the rebels, keep possession of that place, and move thence, in concert with the two regiments just mentioned, towards Charleston, with the view of co-operating with the forces from Ironton and Cape Girardeau towards Benton.

Brigadier-General McClernand, of Illinois, is moving towards Cairo with 2,000 infantry, which he was been instructed to distribute at Centralis and Carbondale, on the Illinois Central Railroad, and at a point opposite Commerce.

It is intended, in connection with all these movements, to occupy Columbus, Ky., as soon as possible. You will therefore, upon assuming the command at Cape Girardeau, act in accordance with all the foregoing dispositions, and when the junction with the forces of General Prentiss is effected, you will take command of the combined forward Ironton.

J. C. FREMONT,

Major-General, Commanding.

SAINT LOUIS, August 28, 1861.

Brigadier General B. M. PRENTISS:

SIR: Brigadier-General Grant has been directed to proceed to Cape Girardeau, assume the command of the forces there, and co-operate with the troops moving from Ironton. When you were ordered to go to Ironton and take the place of General Grant, who was transferred to Jefferson City, it was under the impression that his appointment was of a later date than your own. By the official list published it appears, however, that he is your senior in rank. He will, therefore, upon effecting a conjunction with your troops, take command of the whole expedition.

Brigadier-General McClernand, of Illinois, is moving towards Cairo with 2,000 infantry, which he has been instructed to distribute at important points upon the Illinois Central Railroad and on the shore opposite Commerce, it being the intention ultimately to take possession of Columbus and hold it.

Colonel Waagner, chief of artillery at Cairo, left Saint Louis last night,