HEADQUARTERS ARMY OF THE POTOMAC, OFFICE OF CHIEF QUARTERMASTER,
Camp near Brandy Station, November 18, 1863.

Brigadier General S. WILLIAMS,

Asst. Adjt. General, Army of the Potomac:

GENERAL: I have the honor to report, for the information of the commanding general, that I have examined the capacity of our wagon trains as now allowed by existing orders for carrying of supplies, and find, in round numbers, that each corps can carry ten days' short rations of subsistence and forage in the baggage and supply trains, in addition to the most necessary articles of baggage, camp equipage, &c. To do this, less small-arms ammunition should be carried in wagons. I would suggest that only three wagons, instead of five, be allowed each, 1,000 men for that purpose.

I inclose a memorandum of what a wagon can carry, also a memorandum of the wagons in Sixth Corps and what they can carry. I am on the opinion that a wagon cannot carry over 1,000 rations of subsistence, and, say, 600 pounds of grain. This will make the load over 2,000 pounds. The general depot can furnish wagons enough to carry two days' hard bread and four of salt for the army. This will give twelve days' in wagons, with an extra allowance of salt.

If the men carry eight days' on their persons there will be twenty days' in all. I would remind the general commanding that experience has shown that there is no military advantage in loading the men heavily. they become quickly fatigued and waste the rations. In case of battle they abandon them. If eight days' are carried, hardly more than five can be calculated upon.

In any military operations based on amount of supplies carried in wagon trains, calculations must be made for a fresh supply from some reliable source at the expiration of, say, fifteen days.

The army can be furnished with all its prescribed supplies on or before Friday evening.

I am, very respectfully, your obedient servant,

RUFUS INGALLS,

Brigadier General, and Chief Q. M., Army of the Potomac.

[Inclosure.]

Capabilities of supply of the Sixth Corps, excluding the artillery, computing rations for 18,000 men, at 1,500 pounds weight for 1,000 rations (1 1/2 pounds to a ration), and forage for 2,500 animals, at 10 pounds each. This number of animals includes only those attached to the supply trains and 300 others, estimated not to be provided for otherwise.

Pounds.

18,000 rations weigh. . . . . . . . . . . . . . . . . . . . . . . . . . 27,000

2,500 animals' forage. . . . . . . . . . . . . . . . . . . . . . . . . 25,000

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Daily supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52,000

The number of wagons procurable for supply trains is 226. Estimating their capacity at 2,500 pounds each, makes 565,000 pounds. Divide this by 52,000, gives ten days and a fraction of about four-fifths.

All the wagons included in the supply trains cannot be devoted to rations and forage. Quartermaster's are obliged to carry their blacksmiths' and harness-makers' shops, and commissaries their