Island Numbers 63, below Helena, is occupied by a colony for a home farm, which is entirely self-supporting, and the superintendent, Chaplain Thomas, informs me he will have, when their crops are disposed of, a surplus of over $20,000.

At Helena there are besides the white troops two regiments of colored troops and a battery of colored artillery. Colonel Crooks, the commander, who is an energetic officer, will make excursions into the interior to gather colored recruits to fill up these regiments. He is just ow watching the movements of the enemy on the river to prevent a crossing if such is meditated.

The lines at Memphis have also been brought in, leaving, indeed, a portion of the town beyond them. Here there is a fine regiment of artillery garrisoning Fort Pickering, on the lower flank of the city. This is a very large work, does not control the city proper, and wold take some 10,000 men to man it properly. What has been designed to be an element of strength is really an element of weakness. Since the recent ash of Forrest into Memphis, General Washburn intends to erect limited field-works just beyond the town on roads leading into it, which I think a good-measure. On the 10th ultimo he sent up the river four regiments of 100-days" men; still he has troops sufficient. When his 2,000 cavalry, which he threw across the Mississippi River, returns he contemplates organizing an expedition to move rapidly in the direction of Montgomery and Selma, Ala., if possible, to cut the railroad and release our prisoners near the latter place. If he makes this expedition he would necessarily gather a large number of negroes and thus be enabled to fill up the diminished ranks of the regiments within his district. He has no fears of Forrest's command, knowing that both horses and men are much broken down by their late operations.

The term of service of the two regiments of 100-days" men at Columbus, Ky., having expired, the only troops there will be a regiment of colored artillery, 1,000 strong. This is hardly sufficient for that place and the other points dependent upon it.

Cairo is garrisoned by the One hundred and thirty-ninth Regiment Illinois Volunteers (100-days" regiment). The regiment has consented to remain fifteen days longer. Some provisions must be made for this point, and important depot where troops are constantly passing to and for.

There are evidently very few rebels on the Mississippi River, though small parties do occasionally come to the banks, and, under shelter of the woods, fire into steam-boats. On my way up may boat was twice thus fired into with musketry. A few shots in the first instance, and but one in the second. I was enable to return their fire in both instances.

I shall leave to-morrow morning for Paducah and Louisville. My address will be at the latter place.

I am, sir, very respectfully, your obedient servant,

L. THOMAS,

Adjutant-General.

WASHINGTON, September 11, 1864.

Lieutenant-General GRANT:

It is not designed by this Department to delay the draft a single day after the credits are made up and quota ascertained. The