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 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.