In reply to a letter from General Sherman, by the hand of Judge Williams, in relation to the vast importance of securing possession in advance of the country lying between the Ohio, Tennessee, and Mississippi, I have to-day suggested the first part of the preceding plan. By extending my command to Indiana, Tennessee, and Kentucky you would enable me to attempt the accomplishment of this all-important result; and in order to secure the secrecy necessary to its succeeds, I shall not extend the communication which I have made to General Sherman or repeat it to any one else.

With high respect and regard, I am, very truly, yours,

J. C. FREMONT.

CAIRO, ILL., September 8, 1861.

General JOHN C. FREMONT, Saint Louis, Mo.:

Information received from a spy, and also from Kentuckians who have fled from their homes, report the rebel strength at Columbus to-day at eighteen regiments of infantry and a considerable number of artillery and cavalry. They had two batteries of heavy pieces and two gunboats. One of their gunboats has been up to within 3 miles of Cairo this evening. No troops from Saint Louis to-day.

U. S. GRANT.

HUNNEWELL, MO., September 8, 1861.

Major-General FREMONT:

Did not move last night, because the re-enforcements from Hurlbut did not reach here until 10 p. m.-too late for the object. I have now force enough to move on Green, and will do so to-night. Your dispatch, to make no important movement without further advices, received.

Please answer, and give me authority to move.

JNO. POPE,

Brigadier-General.

HUNNEWELL, MO., September 8, 1861.

Major-General FREMONT:

The road is now open and clear as far west as Platte River. I have heard nothing of the re-enforcements of which you telegraphed.

JNO. POPE.

HDQRS. DISTRICT SOUTHEAST MISSOURI,
Cairo, Ill., September 8, 1861.

Colonel FRED HECKER,

Commanding Twenty-fourth Illinois Volunteers:

I have reliable information that a guard of 500 cavalry, unsupported by infantry or artillery, are now 7 miles from you, on the Cairo and Columbus road. By leaving at 11 o'clock or later I think you will be able to take them. Be exceedingly cautious not to be led too far, and surprise them if you can. I am at the same time fitting out an expedition to try and surprise Jeff. Thompson, who is on the Missouri side of the river about the same distance off. Keep these matters to yourself for to-night.

U. S. GRANT,

Brigadier-General, Commanding.