...Donelson safe, unless Grant shall be overwhelmed from outside; to prevent which latter will, I think, require all the vigilance, energy, and skill of yourself and Buell, acting in full cooperation. Columbus will not get at Grant, but the force from Bowling Green will. They hold the railroad from Bowling Green to within a few miles of Fort Donelson, with the bridge at Clarksville undisturbed. It is u...