I had ridden on for more than an hour, through the darkness, keeping a good look-out for the enemy, whose scouting parties of cavalry were known to be prowling around, when all at once, my horse, who was going at full speed, struck his foot against a sharp point of rock, cropping out from the surface. The animal stumbled, recovered himself, and went on as rapidly as before. A hundred yards further his speed relaxed; then he began to limp painfully; then in spite of every application of the spur I could not force him out of a slow limping trot. It was truly unfortunate. I was the bearer of an important message, and was surrounded by enemies. The only chance was to pass through them, under shadow of the darkness; with light they would perceive me, and my capture be certain. A hundred yards further, and I found I must decide at once upon the course to pursue. My horse seemed about to fall. At every stroke of the spur he groaned piteously, and his limp had become a stagger. I looked around through the trees, and at the distance of a quarter of a mile I saw the glimmer of a light. To obtain another horse was indispensable under the circumstances; and looking to see that my revolver was loaded and capped, I forced my tottering animal toward the mansion in which the light glimmered. My design was simply to proceed thither, “impress” a fresh horse at the pistol’s muzzle; throw my saddle upon him; leave my own animal, and proceed on my way. Pushing across the fields, and dismounting to let down the fences which my limping animal could not leap, I soon approached the light. It shone through the window of a house of some size, with ornamental grounds around it, and apparently the abode of a man of means. At fifty paces from it I dismounted and tethered my horse in the shadow of some trees. A brief reconnaissance under the circumstances was advisable; and approaching the mansion silently, without allowing my sabre to make any clatter, I gained the long portico in front, and went to a window reaching down to the flooring of the verandah. Through the half-closed venetians I could see into a large apartment, half library, half sitting-room, as the easy chairs, mantel ornaments, desks, and book-cases showed. On the centre-table burned a brilliant lamp--and by its light I witnessed a spectacle which made me draw back in the shadow of the shutter, and rivet my eyes on the interior. Before me, in the illuminated apartment, I saw the woman whom Mohun had captured on the Rappahannock; and beside her the personage with whom she had escaped that morning in the wagon from Culpeper Court-House. I could not mistake him. The large, prominent nose, the cunning eyes, the double chin, the fat person, and the chubby hands covered with pinchbeck rings, were still fresh in my memory. The name of this personage had been revealed by Nighthawk. Swartz, the secret agent, blockade-runner, and “best spy in the Federal army” was before me.