920 



Popular Science Monthly 



Which Is the "Dead" Lamp on a 



Series Circuit? An Automatic 



Gut-Out Tells 



culties by providing a device which auto- 

 matically cuts the fibrient of a "dead" 

 lamp out of the circuit and places a re- 

 sistance in the circuit so as to maintain it 

 closed and balanced. Thus the remaining 

 lamps in the circuit are enabled to glow on. 

 The inventor winds a resistance coil 

 around a resistance carrier within the 

 lamp in such a manner that the breaking 

 or burning out of the filament will blow 

 out a fuse. The spring held by the fuse 

 is released, thus introducing the resistance 

 in the circuit and bridging over the gap 

 caused by the burning out of the filament. 

 The trouble and inconvenience formerly 

 caused by the burning out of a single 

 filament in a circuit can thus be reduced 

 to a bagatelle. 



Fu^ecircvjit 



Lightir\g clrcviit 



Figs. 2, 3 and 4 show the 

 three circuits embodied in 

 the lamp separately and 

 Fig. 1, below, a diagram 

 of the complete lamp 



WHEN an incandescent lamp which 

 forms part of a series circuit burns 

 out or when its filament breaks, all other 

 lamps on that circuit are extinguished. 

 The circuit must be bridged around the 

 defective lamp. As all the lamps of the 

 circuit are extinguish- 

 ed, it is a tedious task 

 to find the exact lamp 

 which caused th.e 

 break. Each one has 

 to be tested separate- 

 ly until the burnt-out 

 bulb has been found. 

 Not until then can 

 the circuit be restored, 

 either by substituting 

 a good lamp for the 

 one burnt out or by 

 bridging over the gap 

 in the circuit. 



The incandescent 

 lamp recently invent- 

 ed by F. Wybaillie, of 

 New York, and shown 

 in the accompanying 

 illustration, aims to 

 overcome these diffi- 



Clad in such armor our soldiers would 

 indeed look like Martians or super-men 



The Fifty- Seventh Variety of Armor 

 for the Modern Soldier Appears 



THE soldiers of old went 

 forth to fight clad in 

 cumbersome and expensive 

 armor, which, while serving 

 as a protection, nevertheless 

 hindered them from putting forth their 

 best fighting strength. To-day, Martin 

 Jelalian, an inventor of Rhode Island, has 

 made it possible for a soldier to be pro- 

 tected by armor. He is one of several 

 dozen inventors who have reinvented the 

 coat of mail. 



The device is a bullet-proof metallic 

 structure which sur- 

 rounds the body and 

 extends from the top 

 of the shoulders to 

 below the thighs. This 

 steel coat consists of 

 two like parts held 

 together across the 

 chest by means of 

 straps. Hooks at- 

 tach the coat to 

 semi-cylindrical 

 pieces of metal which 

 fit closely about the 

 upper part of the leg, 

 and are fastened be- 

 hind by straps. The 

 inner surface of the 

 armor is padded. The 

 head is protected by a 

 lined mask composed 

 of the same metal. 



