...while he kept up an active skirmish across the Potomac for two days, an effort was made to break the dam on the night of the 7th, but with little success. Unwilling to be foiled in his undertaking, Jackson again left Winchester on the 16th with a larger force, and on the 17th, having disposed his troops to provide against a flank movement and also to make demonstrations at Dam No. 4, at Williamsport, h...