From the Chicago Post, Aug. 9.

A gentleman connected with this office, who arrived information of one of the most horrible transactions that it has been our lot to record during this war. The boat landed at a place called Compromise, in Tennessee, near the dividing line between that State and Kentucky, where the particulars of the awful affair were learned from the neighbors. On Tuesday last, the 4th inst., eighteen negro soldiers, fully armed, having come from the camp on Island No. 10, went to the house of Mr. FRANK BECKHAM, on the river, immediately at Compromise Landing, and murdered him, aged 40 years; his old father, (Maj. BENJ. BECKHAM, aged 80,) and four children of Mr. F. BECKHAM: LOURA, aged 14; KATE, aged 10; CAROLINE, 7, and RICHARD, 2 years. They first caught Mr. F. BECKHAM and his aged father, tied them, marched them to the edge of the bank of the river, shot and stabbed them, and threw their bodies into the water. They then threw little DICK into the river, tied the two youngest girls together, and threw them in, then forced the oldest girl and beat her over the head with their muskets until she sank down. The bodies of old Maj. BECKHAM and the youngest child have been recovered. Many of the passengers went to the house and saw them. Fortunately two of the family of children were off at school, and the mother and one child, four years old, were at Owensboro, Kentucky. All the rest were murdered.

Twelve of the negroes were caught by our cavalry and are now confined at Island No. 10. Six are yet at large. The immediate motive for the deed was thought to be the fact that Mrs. BECKHAM took up the river with her a negro girl as nurse, whose mother had run off, and was at Island No. 10. The negroes had before endeavored to steel the girl away, but Mr. BECKHAM drove them off with arms.

CAIRO, Friday, Aug. 7.

It appears from a statement made by the Cairo News, of this morning, whose information came from Capt. PHILLIPS, of the United States Navy, that the killing of Mr. BECKHAM and family,; near Compromise Landing, should not be wholly placed upon the shoulders of the colored men. The facts seem to be that, while the soldiers also had a hand in the bloody deed, two white men, one named GRAYSON, were sitting by, and urged on and prompted the negroes to their cowardly acts. GRAYSON has been captured, with twelve negroes and one white man. Five or six colored men are yet to be taken, It is to be hoped that all may be properly punished.