Popular Science Monthlij 



779 



Fig. 3. Suspended 

 air-bag of a football 



The corpse was a pasteboard torso in 

 tlie possession of tlie biological labora- 

 tory, but stufled garments would have 

 been just as ser\iceable. The weird 

 Hghl above it was 

 produced by a 

 Crookcs' tube 

 from the physics 

 laboratory, oper- 

 ated on another 

 small induction 

 coil (Fig. 2, (7). 

 The dead man's 

 hand and fool 

 were of course a 

 glove and stock- 

 ing 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 avail- 

 able in the a\erage high school labora- 

 tory, 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 light- 

 ing 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. Any- 

 thing which is a sudden shock or surprise 

 is valuable. Snakes, rats, bats, and 

 anything suggestive of death or decay 



TO METAL PLATE ON FLOOR 



Fig. 4. Connection of the wires from the 

 medical coil to the footplate and the skull 



will arouse terror in most people; but 

 one boy went through the entire chamber 

 without ha\ing any imjiression 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. 



idea 



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. 



