Page:Popular Science Monthly Volume 89.djvu/793

There was a problem when proofreading this page.

The corpse was a pasteboard torso in the possession of the biological laboratory, but stuffed garments would have been just as serviceable. The weird light above it was produced by a Crooke's tube from the physics laboratory, operated on another small induction coil (Fig. 2, G). The dead man's hand and foot were of course a glove and stocking filled with wet sand. The snakes were real, but artificial ones would have served as well. The 6-in. spark above the door-knob, which was probably the only effect not available in the average high school laboratory, was produced by a large induction-coil operating on a current of about 50 volts, taken through a rectifier and a rheostat from an ordinary electric lighting circuit.

Although there are a number of phosphorescent paints on the market, the paste used in this instance was made from the heads of three or four boxes of matches and a little water. Anything which is a sudden shock or surprise is valuable. Snakes, rats, bats, and anything suggestive of death or decay will arouse terror in most people; but one boy went through the entire chamber without having any impression made upon him. Just as he was going out the door, however, a terrified yell proclaimed that the big rattler had gotten loose in the darkened room. There was really no rattler in the room, but the boy went out thoroughly frightened at last.


��An Alarm- Clock Dinner Bell for Old Dobbin

FROIVI the standpoint of the man about the house, the dollar alarm- clock has filled more long-felt wants than any other modern invention. In these columns alone articles liave already been published telling iiow to open the furnace-door with an alarm-clock, how to control electrical toys with alarm- clocks, and a generous number of inter- esting and ingenious plans for awakening the entire family by alarm-clock sys- tems. The latest alarm-clock will interest the man who either forgets or is too busy attending to other things, to feed his horse.

An alarm-clock is securely fastened to the top of a grain-bin and set to release a door at a certain pre- scribed time. There is a small catch which allows the door to drop. This is operated by a cord running

���Tripping the trap-door with an alarm-clock

��up to the clock and around the alarm- winding key. The alarm is set for the feeding time, and when the key revolves, the string is pulled, the door drops and the grain pours into the trough.

��An Experiment with the Static Electricity from Belts

THE following is a little experiment with static electricity. Take an ordinary electric light bulb, grasp it near the tip, taking care not to get the fingers near the screw-socket on the other end, and hold the bulb near a slipping belt that is generating static electricity, so that the brass almost touches the belt. Sparks will be seen to pass to the bulb, which is then acting as a Leyden jar, and will hold a considerable charge, depending on the size of the bulb. The amount of the charge can very well be apprehended by touching the brass end to a water pipe.

�� �