THE DEMON CORD.
Fig. 24.
Saw a tube in half lengthwise, and at one end mount a grooved wheel, over which passes the bight of a cord, with its two ends passing out of the hollow cylinder at the sides of the other end. Tint one half of the cord a different colour from the other, close it in; varnish well to hide the crack, and your trick is complete.
The cord seems to have the chameleon property of changing its hue.