Over the center of the table hung the gas, which, being incandescent, naturally had a burner with a by-pass, and was easily manipulated by means of a piece of string running up the chandelier, carried across the ceiling where it was painted white, and down to Miss Dolly behind the curtains. A weight should be fastened to the switch to make it fall when not pulled by the string, as in [Fig. 5].
Fig. 4.—Plan of the room of mystery.
When White opened the door the young lady lowered the gas by means of her string, and as it was a by-pass the light did not actually go out, although it went sufficiently low to plunge the room in darkness.
Fig. 5.—The weighted by-pass.
Fig. 6.—An exploding cap.
It was an easy matter to cause a collision between the visitors. A piece of cord stretched across the room, at L, L, quickly did its work, and was then pulled away behind the curtain.
The “Den” had not been fitted up so neatly for beauty alone, and if they had looked, the guests might have found a couple of strong electric bells concealed beneath the dainty hangings of a picture by the door. Dolly had but to push a button and these two bells were set ringing like an alarm clock, and with a persistence calculated to arouse the Seven Sleepers.