.... Longstreet, routed at every point, retreated up the valley, leaving it at daybreak. Four hundred and twenty of our men, and many more of the enemy, were killed and wounded. Hooker thus gained Lookout Valley ; the siege of Chattanooga was raised; the cracker line was opened! The credit of this result is chiefly due to General W. F. Smith, Chief Engineer of the Army of the Cumberland, who conceived th...