I was thus cogitating when a sound reached me. I thought I could distinguish a horse's footfall. I stopped--the sound was louder--coming and coming fast. I dismounted and led my horse into the woods a few yards and covered his mouth with my hands. Still the sounds reached me--the constant cadence of a galloping horse, yet coming from far. Who could be riding fast this night? Who could be riding south this night? The rebels were going north; no rebel horseman would ride south to-night. The sounds increased now rapidly, and soon a single horse dashed by; I could not see the rider for the boughs of the trees, but I saw a black horse going south. Was this the messenger who had outstripped me at the start? I could not know, but the horse was black. Why not brown? How could I be sure that in the moonlight I could tell black from brown, or black from bay? I could not answer, yet I felt confidence in my first impression. The lieutenant had said the man's horse was black. How did the lieutenant know? Had he seen the horse by day? Had he brought a light? The horse must be very black. To satisfy my mind I led my horse into the road and slipped the bridle round his foreleg; then retired a few yards and looked at him--he had not the colour of the black horse; he was a deep bay. Why was the black horse returning? Doubtless the enemy had been found far up the road, and the messenger could not get through them. Who else would be riding fast down this road? If the rider were a rebel, he would ride slow. Our men would ride fast toward our own lines; this rider was one of ours. Who was he? He was the messenger on the black horse. Why should he ride so fast to the rear? He was seeking a new road; perhaps he knew of another road, and was hurrying now because he had already lost time and his new road would be longer and would make him lose more. Yet I went on up the road. I had heard the galloping of the black horse far off, and I knew that I could go half a mile before I should encounter the enemy. I was ahead of the black horse.