Crowning the heights on the outskirts of a certain town on the east coast is a large, iron water-tank from which an isolated row of small villas obtains its supply. The top of this tank has been cemented, and round it have been placed railings, thus making of it a splendid "look-out" for any of the townspeople who may choose to promenade upon it. And very popular it was until the strange and terrible happenings of which I have set out to tell.