P. S.-My division, which had been reduced to a skeleton by the battle at Fair Oaks, June 1, had been filled up by three regiments. After losing 1,500 men by that battle, and by the several engagements of the last eight days, it has lost 1,500 more; and by this morning's report it numbers 7,000 men for duty. I cannot too much commend the admirable manner in which my three brigadier-general - French, Meagher, and Caldwell - have done their duty with their brigades, and the skill with which Captains Hazzards and Pettit,with their batteries, kept down the fire of the enemy.

If anything can try the patience and bravery of troops it must be their fighting all day for five consecutive days and then falling back every night.

No. 12. Report of Captain Rufus D. Pettit,

Battery B, First New York Light Artillery, of engagement at Peach Orchard, or Allen's Farm, battle of Sawage Station, engagement at White Oak, Swamp Bridge, and battles of Glendale, or Nelson's Farm (Frazier's Farm), and Malvern Hill.

CAMP ON JAMES RIVER, July 5, 1862.

SIR: In compliance with orders this day received I have the honor to report that my battery, according to orders, withdrew from its position in Redoubt Numbers 5. of our works before Richmond at 4 a.m. June 29, 1862, and on reaching Allen's farm took a position in battery, where it remained some two hours, when I was ordered to report with my command at Savage Station, and on arriving there was ordered to return to Allen's farm, the enemy having attacked our rear at that place. Arriving here, I took up my former position and opened fire on two of the enemy's batteries which were shelling our position, and succeeded in silencing them, after expending near 200 rounds of shell and case-shot, without loss to my command. Remaining here until 12 m. my battery was again ordered to Savage Station. Then it moved a short distance down the Williamsburg road and took a position in battery. The enemy attacking our rear again with batteries from the wood and railroad, their skirmishers appearing at the same time, I was ordered to a position some 1,200 yards from his batteries, and opened on them with good effect, causing them to slacken their fire, and finally drove them from their position, after expending nearly 400 rounds, having in this engagement 3 men severely wounded and 1 missing.

Placing my sick and wounded on the caissons, the battery moved to White Oak Swamp, which it crossed at 2 a.m. June 30, with the loss of the rear chests and carriages of two caissons by the breaking of the stocks in such a manner as to prevent their being taken farther, and after moving the ammunition the carriages were further disabled by cutting the wheels, boxes, &c. The battery then moved to and took position near General Sumner's headquarters, where it remained until ordered to Nelson's farm to relieve the battery of the gallant Hazzard, which had nearly expended its supply of ammunition, but was still keeping up its fire with good effect under the direction of Lieutenant King, from whom I obtained some knowledge of the whereabouts of the enemy's batteries, their guns masked by the timber, and opened at once a rapid fire, first at 1,200 yards, then 1,500 and finally silencing their guns at 1,800 yards, blowing up one of his ammunition chests.