.../www.w3.org/TR/xhtml1/strict"> regiments and six guns, and by participating gave the odds very largely to Porter. On this same 27th of May, Johnston, having information of McDowell's advance from Fredericksburg , determined to strike a blow at McClellan before that large reinforcement should reach him. He at once began the concentration of his army toward his left, with the intention of throwing the larger p...