...ght on the battle of Ball's Bluff. When armies are on the qui vive for a fight, slight and unforseen causes often bring it on. It was Pettigrew's, march in search of shoes, and his collision with Buford 's cavalry, that precipitated the battle of Gettysburg, and defeated Lee's plan of concentration at Cashtown. So Stone's demonstration at Ball's Bluff deranged McClellan's plan for a general advance...