They were located at a mean distance of 3,525 yards from Fort Sumter, and were in readiness to open fire on the 15th of August.

112. In the meantime Colonel Serrell had been ordered, on the 25th of July, to establish a breaching battery in the first parallel, to be armed with two 200-pounder Parrott rifles and two 80-pounder Whitworth rifles. The use of these guns and the service of a detachment of men to man them had been kindly offered by Admiral Dahlgren. The battery was called the Naval Battery, and was under the efficient command of Captain Foxhall A. Parker throughout the bombardment, which commenced on the 17th day of August.

113. July 27, directed Lieutenant Michie to commence the construction of breaching batteries against Fort Sumter on the land ridges to the left and rear of the Beacon House, near the marsh. These batteries were pushed forward rapidly under the fire of the James Island batteries.

114. A 10-inch Parrott rifle having arrived from the north (the only one used by us in our operations prior to the capture of Fort Wagner), it was decided to locate it on the left, with a view to its security from the enemy's fire. The duty of preparing a position for it was assigned to Lieutenant Michie.

115. The breaching batteries established in this locality were at a mean distance of 4,300 yards from Fort Sumter, and comprised one 10-inch Parrott rifle, two 8-inch Parrott rifles, and four 100-pounder Parrott rifles.

All these pieces took an effective part in the first bombardment of Fort Sumter, from the 17th to the 23rd of August, although some of them did not open until the third day.

116. August 2. Between the 15th and 20th of July, Colonel Serrell and Lieutenant Michie had made several examinations of the marsh to the westward of Morris Island, in order to determine the practicability of placing a battery there, within effective range of the city of Charleston and the shipping at the wharves.

117. This marsh, like other salt marshes on this coast, consists of a bed of soft black mud, from 16 to 18 feet in depth, overgrown with reeds and grass, traversed by numerous deep and tortuous bayous, and subject to daily overflow by the tides.

118. The difficulties which presented themselves, viewing the undertaking as simply an attempt to solve a complicated problem in practical engineering, appeared very great, leaving out of the question the severe artillery fire to which the working parties would be exposed, without the possibility of securing any protection until the battery should be nearly completed.

119. The experience in the marshes on the Savannah River, above Fort Pulaski, in 1862, came to our aid, and contributed largely to the speedy and successful completion of the work.

120. A number of experiments to ascertain the sustaining power of the marsh mud were made, and from the date thus obtained a plan of a battery for one 8-inch Parrott rifle, submitted by Colonel Serrell, was approved, with but slight modifications, and he was charged with its construction.

121. It was located at a point nearly midway between Morris and James Islands, 7,000 yards from the lower end of Charleston City, and was named the Marsh Battery, although it is generally known as the "Swamp Angel," a name conferred upon it by the soldiers. A deep creek directly in front of the battery, across which a strong boom was constructed a few yards lower down, rendered the position secure against attack from infantry or boat parties.