Quincy A. Gillmore to Rear-Admiral DAHLGREN, July 22, 1863

Rear-Admiral DAHLGREN, Commanding S. A. B. Squadron, off Morris Island:

DrEaAR Sir: I am just in receipt of your three letters, two of yesterday and one of to-day, and hasten to reply to them in one communication.

made at the present time. I have made two that were unsuccessful, and do not feel authorized to risk a third just now.

Second. In regard to the safety. of my depot at Hilton Head, I admit that I feel some concern.

You will doubtless remember, admiral, that it was arranged between us—I so understood it, at least—that the Wabash and Vermont should both lie abreast of my depot at Hilton Head during our operations here, just as they did during the last attack on the Charleston defenses. It has been necessary to take the Wabash away, however, in your operations here, and as a consequence I have been obliged to send troops from Morris Island to Hilton Head.

I feel, as doubtless you do, that thorough co-operation between the army and the navy is Reatrattel and that neither branch of the service can at the present moment advance alone. Each has already failed once in the attempt to do so. Too much would be risked if my depots at Port Royal and vicinity were less strongly guarded now than they were at the last attack on Charleston. The navy then kept a gunboat in Calibogue Sound. There is none there now, and I have not requested it, although I feel great concern for the weakness of Hilton Head Island in that direction.

Third. I accept the Whitworth guns and the officers and crews with them, and thank you for the same. I presume you will send one officer to command the whole; if so, when he reports for duty I will assign him a position, give him the necessary general instructions, and afford him facilities for getting up his ordnance and ordnance stores. His guns and men will, of course, remain under his immediate control.

Very respectfully, your obedient servant,