Quincy A. Gillmore to Rear-Admiral JoHN A. DAHLGREN, August 23, 1863

Rear-Admiral JoHN A. DAHLGREN, Comdg. S. A. B. Squadron, off Morris Island, S. C.:

My Dear Sir: I amin receipt of your letter of yesterday, informing me that your contemplated attack on Fort Sumter the night before was postponed in consequence of the grounding of the Passaic.

IT agree with you that the guns of the monitors should not be expended unnecessarily on Wagner, but kept for the interior defenses of Charleston. I have entertained these views all along, and expressed them to you in my letter of the 21st instant.

I consider the offensive power of Sumter entirely destroyed from to-day’s firing. I do not believe ae can serve a single gun.

The gorge wall is breached throughout its entire length, the débris in several places forming a practicable ramp from the level of the water to ae top of the ruins. Many of our shots go through and through both walls and plunge into the water beyond.

Some of the guns from the gorge and the adjacent face lookin toward Cumming’s Point, were doubtless removed to James and Sullivan’s Islands before the bombardment commenced, or during its progress. Advantage may be taken of the darkness now to remove. those that have been dismounted on the other faces.

I desire to call attention to the project frequently discussed and deemed practicable by us both, of investing Morris Island as soon as Sumter should be rendered harmless, and starving the enemy into terms. I think that I can close communication on my left as far out as to include Light-House Creek. Cannot picket-boats be managed between the mouth of that creek and your monitors, so as to complete the investment? This investment ought not, of course, tointerfere with your active offensive operations.

If the wind goes down, I will come out to see you to-day.

Very respectfully, your obedient servant,