Page:Popular Science Monthly Volume 89.djvu/456

 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

�� �