In the O. R. I see aggregate present which is the total # of officers and men present for duty.
That is not quite accurate. The
Aggregate Present includes the personnel "present for duty," but combined with all others present with the unit not doing duty, including the "present sick" or in arrest or confinement, or even on "extra or daily duty" outside the line of battle. For example, from the return of the Army of the Potomac for April 30, 1864:
Aggregate present and absent I assume is present for duty, personnel detailed for other duty (and therefore absent) or on furlough/leave and the sick.
The "
Aggregate present and absent" is practically just an enumeration of the number of names total on the rolls.
So some explanation I might say:
"Aggregate Present and Absent:" The total number of men accounted for on the rolls of the organization described, including all present and absent.
"Absent:" the number of men, among the above, recorded absent from their units for various reasons, like hospitalization, furlough, absent without leave, detached, captured, missing, deserted, etc.
"Aggregate Present:" the sum of categories of men not absent from their units.
"Present for duty:" That portion of the aggregate present doing military duty with their unit.
"Present Sick" or "present in arrest..." etc. etc., viz. those present incapable of doing military duty with their unit as a result of illness or injury, or arrest, confinement, etc. or even detail to extra or daily duty.
A Regimental return would show something like this...
From the common regimental return you can see the "
Aggregate Present" includes the sub-categories of "present for duty," "present sick," or "present in arrest or confinement." It excludes all those absent from their units for whatever reason.
Then towards the right, the
aggregate present and absent is given. The blank spaces would be filled in as necessary.
So for example, looking at this return for some US troops:
The aggregate present and absent of this collection of units is 39,211. Of them, 26,634 comprise the aggregate present (meaning 12,577 were absent). Then notice "present for duty" (who would be among the aggregate present). It numbers 21,968 officers and men.
Comparing that number present for duty versus the aggregate present, shows 4,666 men present who were present but not for duty with it (sick, detailed, arrest, etc.).
Major General Jacob D. Cox, USA, noted post-war that the goal of good military unit administration was, so far as possible, to bring the numbers of "present for duty" as close as possible to the number "aggregate present." As the former excluded the men of the latter who were detailed to extra or daily duty, or headquarters functions for example including clerks, etc. at Army, Corps, Division, Brigade, and regimental headquarters.
So what is aggregate last return?
The "aggregate last return" shows the previously reported "aggregates" for the purposes of comparison with that number reported on each new return.
For example, the "aggregate present and absent" change in this case would regard men deleted or added to the rolls of their units during a period between the returns. Deleted from the rolls would be those died, discharged, dropped, etc., as in removed from the rolls permanently. Also recruits joined and added to the rolls. For example, if in a previous return ten men were discharged for disability or died, but the unit received ten recruits joined in the same period, on the next return there would be no difference in the aggregate "from the last return." As shown on the copy of the return form shown above, the nature of these "alterations" in the aggregate must be accounted for by enumerating the number of deaths, discharges, drops, or recruits joined...
The US and CS armies employed different modes in their calculations which causes sometimes some confusion. For example, besides the aggregates, and the "present for duty" Confederate commands often reported a sub-set of present for duty called "
effective present" which included soldiers actually with and in the ranks of their units. But the US forces had no official similar calculation. From an 1893 observation:
The Confederate "effective" number would have excluded numbers of those who were present for duty, but "ineffective" in some manner, from standing in the rank and file of their units.
An example, from the Confederate Army of Tennessee Return from July 10, 1864 there was an "aggregate present and absent" of 134,254 officers and men (on the rolls), with an "aggregate present" including 73,013 of them, of whom 59,196 officers and men were "present for duty," and among these last was an "effective" force of 50,932 in the rank and file.
Employing this "effective" number might give some deflated view of Confederate numbers.
This because US commands didn't do that generally. They recorded "present for duty" only for the most part. Consequently gives some an inflated view of their battle numbers. For example, Gen. McClellan noted after the war that in the Peninsular campaign in the Spring of 1862, that of about 85,000
present for duty in his Army of the Potomac, perhaps 17 or 18,000 of them were not in the ranks "available for battle..."
Later that year, McClellan's army fought at Antietam with ca. 87,000
present for duty reported by Gen. McClellan. But as Gen. Palfrey observed later the number "present for duty" does not record how many men were physically in the rank and file which was always somewhat less, maybe
4/5ths at best, and frequently less.
Estimates of McClellan's combat number engaged out of the 87,000 present for duty, were as low as 48,000... (from New York at Antietam)...
But others say perhaps 60,000, and Gen. Palfrey says certainly certainly not more than 70,000 on an optimistic level.
On some occasions, when the information was available, US commanders would report the number of "present for duty, equipped," to show how many enlisted men were combat capable, among the "present for duty." This was not exactly analogous to the Confederate "effective" calculations, as it regarded equipment rather than the soldier's disposition, and included all enlisted men (not just those physically in the rank and file, as in the Confederate's effective number)...
Bringing the