ENGINEER BUREAU, Richmond, November 18, 1862.

Captain THEODORE MORENO,

In Charge of Chatanohoochee River Defenses, Columbus, Ga.:

CAPTAIN: There are some points in your recent communications which have not been answered and which merit consideration: First, with regard to the obstructions to be placed in the Chattahoochee. Such obstructions, in my judgment, and with the light before me, should consist of a row, or, better still, two parallel rows of square cribs, placed with salients up and down stream and built up to low-water mark, to which floating obstructions, consisting of a raft of rafts, should be attached, as an obstruction to the progress of the enemy in every stage of water. Each of these cribs should be about 12 feet from its neighbor, and so placed as to protect the interval in the parallel row, distant say 30 feet. I am sorry to inform you, after due inquiry, that the supply of ordnance is so limited that nothing better can be suggested apparently at present than to have the 18 and 24 pounders at Alum Bluff mounted on siege carriages for defending the lower obstructions at Rock Bluff, while the five 32-pounders are mounted at Fort Gaines to defend the upper in its vicinity.

At both of these points it might be well to make further preparations for the heavier ordnance called for by you, and which perhaps can be furnished at a future day. The necessary implements, carriages, &c., to put the ordnance now on the river in a complete state of efficiency can, I am informed by the ordnance department, be obtained from the arsenal at Macon, Ga., and it would be well for you to suggest to the senior captain of the two artillery companies mentioned in your letter to make the necessary requisition on the officer in charge of the arsenal, subject to the approval of the general commanding the department.

General Beauregard has been informed by telegraph of your being in charge of the defenses of the Chattanohoochee, and will, I doubt not, receive any communications or suggestions you may have to make with due consideration.

By direction of Colonel J. F. Gilmer:

Very respectfully, yours,

A. L. RIVES,

Major and Assistant to Chief Engineer.

OFFICE CHIEF COMMISSARY, Savannah, November 18, 1862.

General H. W. MERCER, Commanding, &c.:

GENERAL: Referring to my letter of November 12, I beg to make some additional remarks, which I respectfully request you to submit to General Beauregard if they meet your approbation.

In that letter I informed you that speculators had already offered $1.25 per bushel for corn. Since then $1.50 per bushel has been freely offered, and such large quantities shipped out by speculators that the supplies for this army, commanded by you, are in great danger of not arriving.

Virgil Powers, superintendent of the Southwestern Railroad, writes that so much corn is offered for shipment by individuals the finds it difficult to transport Government corn.