“I had cross-examined Weymouth closely regarding the phenomenon of the bell-ringing, and an exhaustive search of the premises led to the discovery that the house was in such excellent condition that, from ground-floor to attic, there was not a solitary crevice large enough to admit of the passage of a mouse.”

I suppose I must have been staring very foolishly indeed, for Nayland Smith burst into one of his sudden laughs.

“A mouse, I said, Petrie!” he cried. “With the brace-and-bit I rectified that matter. I made the holes I have mentioned, and before each set a trap baited with a piece of succulent, toasted cheese. Just open that grip!”

The light at last was dawning upon my mental darkness, and I pounced upon the grip, which stood upon a chair near the window, and opened it. A sickly smell of cooked cheese assailed my nostrils.

“Mind your fingers!” cried Smith; “some of them are still set, possibly.”

Out from the grip I began to take mouse-traps! Two or three of them were still set but in the case of the greater number the catches had slipped. Nine I took out and placed upon the table, and all were empty. In the tenth there crouched, panting, its soft furry body dank with perspiration, a little white mouse!

“Only one capture!” cried my companion, “showing how well-fed the creatures were. Examine his tail!”

But already I had perceived that to which Smith would draw my attention, and the mystery of the “astral bells” was a mystery no longer. Bound to the little creature’s tail, close to the root, with fine soft wire such as is used for making up bouquets, were three tiny silver bells. I looked across at my companion in speechless surprise.

“Almost childish, is it not?” he said; “yet by means of this simple device the Gables has been emptied of occupant after occupant. There was small chance of the trick being detected, for, as I have said, there was absolutely no aperture from roof to basement by means of which one of them could have escaped into the building.”

“Then...”