Weyrother obviously felt himself at the head of the movement which had now become irrepressible. He was like a horse harnessed to a wagon and running downhill.
That second sentence makes it so vivid-- and for me, such vivid imagery, droplets of it sprinkled throughout, keep me gratefully reading. (Without them, the book falls flat and reader puts it down.)
"He has forty thousand men, if that," Weyrother replied, with the smile of a doctor being told by a wise woman how to treat a patient.