Bog took a half dollar in his hand, advanced to the door, which was now closed, and boldly opened it. The athletic guardian of the place, being confronted with this audacious youth in old clothes, put on a commanding look, and said: "Well, sir, and what the d----l do you want here?" "Only to give you half a dollar, as I was told to," said Bog, "and to ask if Mr. Van Quintem was in. Note from a lady, sir; that's all." Bog winked. The servant smiled, and took the coin. "He's in," was the reply. "Then please hand this to him, and say as how it's 'mportant. No arnser wanted." The servant received the note, and sententiously remarked, "Consider it done;" whereon the boy Bog hurriedly retreated, and hid himself in a doorway nearly opposite. He had hardly done this, before the door of the house opened again, and disclosed the man whom he longed to see. The letter was crumpled in his hand, and his pale face betrayed agitation. He cast wary looks in all directions, and then descended to the sidewalk, and walked fast down Broadway. Bog emerged from his seclusion, and followed him at a distance, always keeping somebody between him and the object of his pursuit. At the corner of Astor Place, young Van Quintem stopped; and Bog came to a halt also, half a block behind. The next minute, the Eighth-street stage, going up, approached the corner at a rapid rate, as if the driver were hurrying home to his supper. There were but few persons in the stage. Young Van Quintem hailed the conveyance, jumped in before it could stop, and the driver whipped up his horses to an increased speed. Bog was tired, and he knew not how far he might have to follow the stage at a full trot. He resolved upon his course instantly. Turning the corner of Clinton Place, he ran up that side of the triangular block, and met the stage. He pulled his old cap farther over his eyes, to prevent the possibility of recognition by young Van Quintem, and, gliding swiftly behind the stage, when he was sure that the driver was not looking, hooked on to the step behind, just as he had done a thousand times when he was a smaller boy. CHAPTER VI. TRACKED. Young Van Quintem sat at the farther end of the stage, absorbed in his own thoughts. His thin lips moved restlessly at times, as if he were arguing to himself. In his hand he still held the crumpled note. Twice he unfolded it, and read the contents carefully; then crushed it in his hand again. Bog watched him through the window of the stage door--not looking straight at him, but with that side vision with which we trace the outline of faint comets. He was aware that young Van Quintem looked at him twice suspiciously, and then settled back into his own meditations. Bog felt safe in his disguise--or rather his original and native dress.