“Call for the police, Ed!” Kelson gasped, “the police—­or—­” But before he could utter another syllable, walls, floor and ceiling shook with loud, devilish laughter.  There was then silence—­enthralling, impressive, omnipotent silence—­the electric light went out—­and the room filled with luminous, striped figures.

[Illustration:  THE ROOM FILLED WITH LUMINOUS, STRIPED FIGURES]