Bell, our guide and scout, in a small boat; next myself, Mr. De l'isle, and the crew, Captain Mickler and his men being next to us in the third boat. The night was very dark, and, though a mistake of our guide, we lost our way in the numerous creeks leading to Light-House Inlet. After nearly four hours' pulling, it being most too late to operate, I had to return to the camp, and wait for the next night. In the meantime, I obtained 3 men from the Eqtaw Regiment, from Legare's Point, and perfectly well acquainted with the localities. I then, observing the same order, started Sunday at 8 p. m., and arrived safely at the contemplated spot, from 400 to 500 yards this side of the Yankee fleet on Light-House Inlet. At 11 o'clock the first line was towed across the channel and cast off, it being 190 feet long, with floats every 10 feet, and a torpedo, containing 50 rounds of powder, attached to each end. At half past 12 I had the work completed, and set four lines adrift toward the Yankee fleet. We heard three loud reports from that direction at the time we were making preparations to leave, but were not able to ascertain the result. Monday, at 6 a. m., we heard a very loud report, and an enormous volume of smoke enveloped the whole fleet. Shortly after a three-masted steamer was seen lying on her beam. There was also a change observed in the position of the shipping. I was to renew the operation to-night, but was ordered to wait for further orders. I accordingly returned to the city, with boats and hands. I am now getting ready to operate on the ship-channel, off Fort Sumter, with float lines and stationary torpedoes, and expect to be ready to begin to-night.

Very respectfully, your obedient servant,

M. M. GRAY,

Captain, in Charge of Submarine Batteries and Torpedoes.

BATTERY WAGNER, August 18, 1863-8.25 p. m.

Major HENRY BRYAN,

Assistant Adjutant-General:

SIR: I have the honor to present the following suggestions for the consideration of the general commanding:

From the apparent effect of the enemy's Parrott shells upon the walls of Fort Sumter, it appears almost evident that the fort will, in time, become untenable by us, and will have to be abandoned and destroyed. The loss of Sumter will necessitate the evacuation of this post and Battery Gregg, and our falling back to our second line of defense.

Before doing so, I would respectfully suggest that the two 10-inch columbiads here and the guns at Battery Gregg be removed from the island to a place of safety. This can be readily accomplished, should the general commanding decide it necessary to take such steps, in one night, or two at the most, and without the enemy's knowledge.

They can be dismounted, and, with their carriages, sent to Cumming's Point and placed on flats, which would carry them to a place of safety. False guns can be placed in their present positions, to deceive the enemy.

I remain, your obedient servant,

C. E. CHICHESTER,

Captain, and Chief of Artillery.