Major-General McClellan: Governor Curtin telegraphs me:
``I have advices that Jackson is crossing the Potomac at Williamsport, and probably the whole rebel army will be drawn from Maryland.''
Receiving nothing from Harper's Ferry or Martinsburg to-day, and positive information from Wheeling that the line is cut, corroborates the idea that the enemy is recrossing the Potomac. Please do not let him get off without being hurt. A. LINCOLN.