The pathetic letter, which was composed by the suffering and dying men at Andersonville, and addressed to the President in August, 1864, and forwarded by the prisoners who were sent to Charleston, led to renewed efforts on the part of the United States government; but no notice was taken by the rebel authorities of the plea in behalf of humanity. The following letter is said to be the one sent to the President:-- _The Memorial of the Union Prisoners confined at Andersonville, Georgia, to the President of the United States._ CONFEDERATE STATES PRISON, CHARLESTON, S. C., Aug., 1864. TO THE PRESIDENT OF THE UNITED STATES: The condition of the enlisted men belonging to the Union armies, now prisoners to the Confederate rebel forces, is such that it becomes our duty, and the duty of every commissioned officer, to make known the facts in the case to the government of the United States, and to use every honorable effort to secure a general exchange of prisoners, thereby relieving thousands of our comrades from the horror now surrounding them. For some time past there has been a concentration of prisoners from all parts of the rebel territory to the State of Georgia--the commissioned officers being confined at Macon, and the enlisted men at Andersonville. Recent movements of the Union armies under General Sherman have compelled the removal of prisoners to other points, and it is now understood that they will be removed to Savannah, Georgia, and Columbus and Charleston, South Carolina. But no change of this kind holds out any prospect of relief to our poor men. Indeed, as the localities selected are far more unhealthy, there must be an increase rather than a diminution of suffering. Colonel Hill, provost-marshal general Confederate States army, at Atlanta, stated to one of the undersigned that there were thirty-five thousand prisoners at Andersonville, and by all accounts from the United States soldiers who have been confined there, the number is not overstated by him. These thirty-five thousand are confined in a field of some thirty acres, enclosed by a board fence, heavily guarded. About one third have various kinds of indifferent shelter, but upwards of thirty thousand are wholly without shelter, or even shade of any kind, and are exposed to the storms and rains which are of almost daily occurrence, the cold dews of the night, and the more terrible effects of the sun striking with almost tropical fierceness upon their unprotected heads. This mass of men jostle and crowd each other up and down the limits of their enclosure in storms or sun, and others lie down upon the pitiless earth at night with no other covering than the clothing upon their backs, few of them having even a blanket.