Confession of a Murderer.—Oben Reynolds, in jail at New Bedford under sentence ot death for the murder of John Bullock, has placed in the hands of the jailor, says the New Bedford Mercury, a written confession ol his guilt. On the day of the murder he went out, as he says, without any intention or thought of committing murder, but for the deliberate purpose of robing some one, fortifying his courage with rum, into which lie had put powder. Meeting Bullock, ho seized his horse by the head, when the deceased smiled at him and pulled on the reins to Blurt up the horse. Reynolds then fired his gun, when Bullock jumped from the wagon and ran towaids Aseonet.The former overtook him, struck him with his gun, clenched, and succeeded in throwing him down, when Bullock holding him by tbo neck, Reynolds stabbed him, us ho says, until he let go his hold ; Bullock meanwhile begging him to spare his life and promising, in ease he did, never to appear ogamst him. After rilling the deceased, who was not then dead, ol his watch and pocket book, ho went home. He says he does not know' where ho threw his gun, but his clothes ho concealed under the bushes in a pond hole near the house, and hid the watch and pocket book in the woods.Reynolds is not over 20 years of age, and has been allowed to grow up in ignorance and vice, lie has learned to read and write since his committal.The property of Bullock was found in the woods m the spot described by Reynolds.