New York, July 30. — The Tribune's Morris Island correspondent says our entire loss in the late assault on Fort Wagner, according to the official report, is 1,517. The rebels claim to have buried 650 of them. This extraordinary proportion could only have been reached by an indisorimate slaughter.
The officers and men of the 54th regiment Mass., (colored,) will not be given up, and unofficial reports say the negroes have been sold into slavery and the officers treated with unmeasured abuse. In fact, all our wounded at Charleston have been treated most barbarously.
Opportunities to amputate were asked upon by rebel surgeons, and it was performed in cases of the slightest gunshot wounds.
On the left our batteries wore advanced six hundred yards nearer Sumter. On the 25th the six 200-pounders were placed in position.
NEW York, July 30. — The Paul Jones (gunboat) arrived this morning, from Charleston harbor Sunday evening. She is ordered here for repairs, being leaky.
The siege of Fort Wagner was progressing when she left. Gen. Gilmore had succeeded in erecting a battery of heavy siege guns within one thousand yards of the fort, and everything was progressing favorably.
Sumter and Ft. Johnston, on James Island, kept up a fire on our forces, but the casualties average but about six per day. The troops and navy are in fine spirits.
Brig. Gen. Strong died this morning, from wounds received at Ft. Wagner.
A Washington correspondent states that the president will visit New England soon.
By passengers by the Cosmopolitan it is learned that the principal guns of Fort Wagner have been silenced. Reinforcements are said to have reached Gilmore, besides several 200 and 300-pounder Parrott guns.
Rebel officers are especially exasperated at being attacked by the 54th Massachusetts. On being asked for the body of Col. Shaw, the rebel reply was, "he has been buried along with his niggers."
Offensive operations by Gilmore are being actively prosecuted.