The enemy opened at one o'clock P. M., from about one hundred and fifty guns. They concentrated upon my left centre, continuing without intermission for about three hours, at the expiration of which time he assaulted my left centre twice, being, upon both occasions, handsomely repulsed with severe loss to them, leaving in our hands nearly three thousand prisoners. Among the prisoners are Major-General Armistead, and many colonels and officers of lesser note. The enemy left many dead upon the field, and a large number of wounded in our hands. The loss upon our side has been considerable. Major-General Hancock and Brigadier-General Gibbon were wounded. After the repelling of the assault, indications leading to the belief that the enemy might be withdrawing, an armed reconnoissance was pushed forward from the left, and the enemy found to be in force. At the present hour all is quiet. The New York cavalry have been engaged all day on both flanks of the enemy, harassing and vigorously attacking him with great success, notwithstanding they encountered superior numbers, both of cavalry and artillery. The army is in fine spirits. GEORGE G. MEADE, _Major-General Commanding_. On the morning of the Fourth of July, General Meade issued an address to the army: HEADQUARTERS ARMY OF THE POTOMAC, Near Gettysburg, July 4. The commanding general, in behalf of the country, thanks the Army of the Potomac for the glorious result of the recent operations. Our enemy, superior in numbers and flushed with the pride of a successful invasion, attempted to overcome or destroy this army. Utterly baffled and defeated, he has now withdrawn from the contest. The privations and fatigues the army has endured, and the heroic courage and gallantry it has displayed, will be matters of history to be ever remembered. Our task is not yet accomplished, and the commanding general looks to the army for greater efforts, to drive from our soil every vestige of the presence of the invader. It is right and proper that we should, on suitable occasions, return our grateful thanks to the Almighty Disposer of events, that, in the goodness of His providence, He has thought fit to give victory to the cause of the just. By command of MAJOR-GENERAL MEADE. S. WILLIAMS, _A. A.-General_. It is fitting we should close this chapter with President Lincoln's brief yet comprehensive announcement to the country: WASHINGTON, D. C., July 4, 1863, 10 A. M.