At least three-fourths of this manual labor was simply shoveling sand; one-half the remainder was carrying engineer material. The balance was employed in various kinds of work.
About three-fourths of this work was executed during 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 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 2,000 to 4,000 yards from our works; Fort Sumter and Battery Gregg were respectively about 3,500 and 2,100; Fort Wagner was from 1,300 to 100 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 150. When it is considered that on an average over 200 men were constantly engaged in these duties, being under fire for nearly fifty days, the number of casualties is astonishingly small.
The camps at which the fatigue parties were quartered and fed were, in order to be beyond the reach of the enemy's fires, 2 miles from the center of the works; hence the distance of 4 miles had to be marched each tour of duty, which required nearly two hours, and added greatly to the labor of the siege.
This siege has been conducted through the hottest part of the season-July, August, and September-yet the troops have suffered but little from excessive heat, on account of the large proportion of night work, and the almost constant sea breeze, which was always cool and refreshing.
The amount of sickness was great, the large amount of duty being the probable cause. On the 7th of August the percentage was the smallest observed during the siege, being 18.6. At this date the aggregate garrison of Morris Island was 9,353, of which 1,741 were sick. On the 17th of August, 22.9 per cent. of the whole garrison were on the sick list. This was the most unhealthy period of the siege.
The average strength of the command on Morris Island during the siege was, of all arms, 10,678 men, of which the average percentage sick was 19.88. The number of black troops varied from 1,127 to 1,947.
Average percentage of sick artillery.................... 6.2
Average percentage of sick in engineers................. 11.9
Average percentage of sick in black infantry............ 13.9
Average percentage of sick in white infantry
(excluding one brigade).................................. 20.1
This brigade consisted of the Ninety-seventh Pennsylvania, Twenty-fourth Massachusetts, and Tenth Connecticut Volunteers. It averaged 32 per cent. sick. This was due to the fact that these three regiments had been stationed, before moving to Morris Island, on Seabrook Island, which proved very unhealthy. The engineers and black infantry served as guard of the trenches, as well as for work in the same.
Details from the troops on Folly Island took part in the operations on Morris Island.