And as if to make the matter still more plain, even as they gazed upon the apparition through the palings of the graveyard fence, the words were repeated again. "Again I say to you, my son, seek not the parchment. Watch and wait, for the day of vengeance is at hand." Suddenly the figure of the woman had come to a halt. Raising one thin hand aloft to the starlit sky above, these words escaped her lips. Then advancing with a gliding movement among the crumbling stones of the old burial ground, the outline of her form seemed to fade away in the darkness, to mingle with the shadows of the great church, of the snow-capped tombs. It was all the work of an instant. Not half the time was consumed in the happening that has elapsed in telling the tale. As though animated by a common thought, the detective and young Frank Mansfield had leaped toward the church-yard wall. The fence offered no obstacle. They dropped in the snow among the headstones. "After her, boy!" whispered Hook. "After her without an instant's delay; there's some crooked work going on here, and it will go hard with some one, but I'll find out what it is." But Frank Mansfield did not heed him. He no more believed in ghosts than did Caleb Hook. If the woman by the side of whose dead body he had knelt in the house on Catherine street had been his poor, insane mother, driven mad by such a combination of afflictions as woman is seldom called upon to bear, then who was this? He needed no encouragement from the man by his side to spur him on to solve the mystery for himself. The day had been clear and more than unusually warm, causing the snow to soften considerably, but as night had approached the thermometer had fallen, forming a hard crust upon the smooth surface among the stones. With a bound Frank reached the point in the church-yard at which the apparition had appeared, Detective Hook pressing close behind. It was unoccupied by human form. The headstones were there, the shadows of the church were there, the leafless branches of the great trees rattled gloomily above their heads. But the woman whose warning words had fallen so plainly upon their ears was nowhere to be seen. She had disappeared--disappeared, leaving no trace behind. There was not so much as the outline of her footsteps to be seen upon the hardened crust of the snow. "Come," whispered Hook, "this is the way she went, over toward the New Church street wall. She cannot get out; there are but two gates, and both are locked at night; it is twenty feet to the ground on the side towards which she disappeared, to say nothing of the fence she would have to climb." They picked their way among the tombs to the rear of the church. Here, in the cold starlight, the entire expanse of the church-yard was plainly visible from the fence on the Rector street side to the wall of the great Trinity Building at the upper end. Not the faintest trace of the woman could be seen.