tery consist of one 200-pounder and four 100-pounder Parrott guns. From this time forward, a party of 150 men worked during the day, and one of 100 men at night, with the usual quota of engineer troops.

On the 12th of August, your ordered that an elevated battery be prepared for the 10-inch rifle Parrott gun, or 300-pounder, which would be protected from James Island rebel batteries, and have full command of the channel from a little to our left of Fort Sumter, sea-ward. All of the above batteries were completed, and engaged in the reduction of Fort Sumter by the 17th of August. It should be remarked, however, that as soon as a gun could be used it commenced firing at once without waiting for the completion of the battery. The details were often obliged to suspend labor, during the very severefiring that the enemy directed against these batteries from James Island and Battery Gregg, although ordinarily their fire wa unheeded. In addition to the construction of these batteries, the above details were engaged in repairing traverses, constructing new magazines for the seven 30-pounder battery on the right, in raising and strengthening the parapet, and making new embrasures for the 200-pounder gun battery in front of the latter, and in constructing and laying new platforms for the two 10-inch seacoast mortars to the left and rear.

The batteries (except that of the 300-pounder) were full sunken. The line of each interior crest made an angle varying from 30 degrees to 37 degrees with the gorge of Fort Sumter, depending upon the nature of the ridge at the different points. The width of each gun battery was 18 feet, the traverse between being 12 feet thick at top. The interior revetments were of sand-bags laid in the usual manner of headers and stretchers, and extended below the gun platform. The embrasures have oblique directrices, and were constructed at first to admit of firing only on Fort Sumter, but, after its reduction, the field of fire was increased to embrace Fort Johnson and Battery Gregg, and finally the James Island batteries and Fort Wagner. A revetment of raw hides soaked and tightly pinned down was first tried on one of the embrasures, and although, on drying, it was tight and apparently promised least resistance to the blast of the gun, it proved but a temporary and indifferent revetment for guns of this caliber. The gabion revetment was subsequently used in all the embrasures. The method of anchoring them was to lay a piece of 6-inch by 8-inch timber parallel to the check, and some 3 to 4 feet back, having two stout anchoring stakes 6 feet long driven on the inner side. Each gabion, besides being well picketed to the fascine upon which it rested, was tied to this timber by Numbers 10 wire, stoutly enough to withstand the blast, and yet to give way if struck by a shot, without destroying the entire embrasure.

The exterior slopes of the batteries were left in the rough, no attempt being made to finish them smoothly, by wasting labor that was sorely needed elsewhere. A coating of marsh mud, about 1 or 2 inches thick, was spread over the exterior slopes and on the tops of the magazines and traverse, which on drying became a hard crust, and prevented the sand from blowing into the faces of the gunners and in the muzzles and other parts of the piece and carriage; a precaution amply appreciated by all who served in the batteries.

There were two magazines, one between Nos. 2 and 3, for the service of the two right pieces, and one on the left of Numbers 5, for the service of the remaining three guns. The former was 10 feet by 10 feet by