That she was beyond all question insane was perfectly clear. Her remarks were most incoherent, and yet they bore direct reference to the subject weighing most heavily upon the mind of Detective Hook: the robbery of the Webster Bank. "He robbed the bank! He robbed the bank! I warned him, but he would not heed." This was her sole answer to the questions the detective had pressed upon her, mingled with muttered words of thankfulness to the "bats in the wall." Now nine men out of ten, under similar circumstances, would have arrested this woman at once. Detective Hook was of a different sort. Let him arrest this woman mad beyond a doubt--and, save for such vague information as could be drawn from her muttered ravings, her usefulness would at once be destroyed. Follow her, and there was no telling where she might lead him--possibly to the abode of the bank-robbers themselves. That she had seen those who blew open the vault, either enter or leave the bank, from her rambling words the detective became firmly convinced; so he let her go, and, dropping all else, followed her through the streets on that Sabbath morning. If nothing came of it he could at least arrest her whenever he pleased. And a long road she had led him, until at the Catherine Market we find them now, with Caleb Hook seriously debating in his mind whether it would not be best to take her in charge at once and end this so far useless chase. Crossing Cherry street, the woman pushed her way among the old clothes dealers and second-hand venders whose baskets were crowded together in the snow-covered street upon this side, and passing along the wall of the market itself, paused among the fish-mongers who cluster opposite the ferry gate. "Fresh fish this morning, ma'am?" cried a runty vender, well wrapped up in a coat that looked as though it might have done service in the days of Noah's flood. "Blue-fish, weak-fish, flounders, sea-bass, eels. Any kind you want you'll find right here!" But the woman did not heed him. Moving slowly on among the baskets, she passed the front of the market and crossed the street to the other side. There she turned, and proceeding perhaps half way up the block, stopped before the window of a low rum-shop, and, raising her hand to her forehead, stood peering in behind the corner of the battered curtain which shielded its lighted interior from the gaze of an over-inquisitive outer world. "At last she stops," muttered the detective to himself, as he took his station by the side of the old hotel on the corner of Catherine street and South, watching to see what her next move would be. "Now, whose place is that, I wonder, and what does she expect to see?" He glanced at the sign above the door of the groggery. "The Donegal Shades, by P. Slattery," was the way it read. It was evidently a saloon for the accommodation of the marketmen, open at this early hour on Sunday morning in defiance of the law.