Annexed to these reports is also a statement of the labor days of the troops.
"WORKING PARTIES AND HEALTH OF TROOPS.
"The total number of days' work, of six hours each, expended in Major Brooks' operations was, by engineers, 4,500, and by infantry 19,000, total 23,500; of the 19,000 days' work by infantry, one-half was performed by colored troops. In addition to the above, 9,500 days' work was expended in preparing siege materials for Major Brooks' operations. The infantry soldiers' days' work is about one-fifth what a citizen laborer would do on civil works. Of my work, over eight-twentieths was against Wagner, about seven-twentieths on the defensive lines, and nearly five-twentieths on the batteries against Sumter.
"The approximate amount of labor actually expended on the more important works is as follows: One emplacement for a siege piece, 40 days; one emplacement for a heavy breaching gun, 100 days; one bomb-proof magazine, 250 days; construction and repairs of each yard of approach having splinter-proof parapet, 2 days; a lineal yard of narrow splinter-proof shelter, 4 days; a lineal yard of wide splinter-proof shelter, 8 days; to make and set one yard of inclined palisading, 2 days.
"At least three-fourths of the manual labor was simply shoveling sand; one-half of the remainder was carrying engineer material. The balance was employed in various kinds of work.
"About three-fourths of this work was executed in the night-time, and at least nine-tenths of it under a fire of artillery or sharpshooters, or both. The sharpshooters seldom fired during the night. The artillery fire was most severe during the day. Thirty-five projectiles fired by the enemy at our works per hour was called "heavy firing," although sometimes more than double that number were thrown.
"In the order of their number the projectiles were from smooth-bore guns, mortars, and rifled guns.
"The James Island batteries were from two thousand to four thousand yards from our works; Fort Sumter and Battery Gregg were respectively about three thousand five hundred and two thousand one hundred; Fort Wagner was from thirteen hundred to one hundred yards.
"The total number of casualties in the working parties and the guard of the advanced trenches, (not including the main guard of the trenches), during the siege, was about one hundred and fifty. When it is considered that on an average over two hundred men were constantly engaged in these duties, being under fire for fifty days, the number of casualties is astonishingly small.
"The camp at which the fatigue parties were quartered and fed were, in order to be beyond the reach of the enemy's fires, two miles from the centre of the works; hence the distance of four miles had to be marched each tour of duty, which required nearly two hours, and added greatly to the labor of the siege.