442 



Popular Science Monthly 



A Convenient Arrangement for 

 Turning on the Hall Light 



W MII.lv nearly all new buildings are 

 wirc-d SI) that the hall lijiht can be 

 turned on and off from either floor, the 

 older buildings do not have this con- 

 venience. The cost of installing cross 

 switches is considerable, but an arrange- 

 ment that will serve the purpose can be 

 instalkxi at slight expense. 



Get a chain socket for the lamp. Tie 

 a cord to the chain, run it through two 

 eyelets as shown in the sketch, and 

 fasten the other end of the cord to the 

 newel post at the head of the stairs. The 



Where There Are No Cross Switches This 

 Method of Control Will Answer 



entire cost will be fifty cents for the 

 chain socket. If you do not care to put 

 screw eyes in the woodwork, loops made 

 from heavy wire can be tied to the 

 banister rails. Any other method of 

 conveying the cord to the newel post 

 might prove equally as satisfactory and 

 inconsjjicuous. — E. F. Ayres. 



Guying the Mast 



IN putting up an aerial, one very 

 essential feature, seldom mentioned 

 by the authors of e.xixrimenlal wireless 

 books, is the necessity for a strong lirace 

 at the top of the mast. It is a good 

 plan in erecting a mast, to adjust a gu\' 

 wire so that it will pull back diri'cth- 

 against the strain of the aerial. Otiur- 

 wise the top of the pole will lean inward 

 and perhaps break oil. 



Wiring the Ford Automobile for 

 Magneto and Battery 



WHILE the Ford owner has been 

 impressed b\' the simplicit\- and 

 cheapness of his magneto lighting system, 

 he has found many serious faults. If he 

 slows down for bad roads, the voltage 

 drops and his lights become wretchedly 

 dim. If he speeds on a bit of smooth 

 road, the \oltage rises and burns out 

 his bulbs. It is then he longs for a good 

 storage battery. Howe\er, he does not 

 like to gi\e up the use of the magneto. 

 Its light is fine for city dri\ing and 

 ordinary travel. If he only could snap 

 on the battery for emergencies! How 

 can he wire his car to use both? 



The difficulty is due to the fact that 

 his magneto furnishes a twel\-e-volt 

 current and his i)atler\- but six. With 

 magneto, two six-volt headlights must 

 be wired in series to pre\'enl burning out. 

 If he uses the battery, the wiring must 

 be changed to parallel or the lamps will 

 not receive pressure enough to light 

 ihem. 



He can easily solve the problem by 

 mounting a three-pole two-throw switch 

 on left of dash within eas\- reach and 

 making connections as shown in the ac- 

 companying diagram. 



When the handle is thrown up, three 

 knife blades close the gaps h and connect 

 the battery parallel with the headlights. 

 When the handle is down, the two outer 

 blades close the gaps w and connect 

 the magneto .1/ in series. 5 represents 

 a couple of snap switches. These 

 should both be snapped on whenever 

 light is needed antl the three-pole switch 

 will instantly change from one current 

 to the other — S. D. Bates. 



Diagram of Connection of Three-Pole 

 Two-Throw Switch on Ford 



