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Page:Popular Science Monthly Volume 89.djvu/649

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Popular Science Monthly

��635

��To Change a Gas Lamp into an Electric Light

TO cliangc from gas to electric liglu on motorcycle headlights and retain the convenience of both, all thai is necessary is to solder a cande- labrum socket to the old burner. Care should be taken to have the burner just the right height so that the lamp can be focussed prop- erly.— F.G. Daly.

���Best Wavelengths for Certain Distances

IT has been figured out that for sending 700 kilometers the best wavelength is only 275 meters, in so far as the condi- tions between the two stations are concerned. For 1000 kilometers, the best wave is about 560 meters long, and for 1500 kilometers about 1250 meters. This computed result may be greatly modified by the characteristics of the sending and receiving antennas, however.

Lighting an Oil- Stove with an Alarm- Clock on Cold Mornings

NO one really enjoys getting out of lied on a cold morning before the room is heated. And it is not really necessary; for with an oil-stove, an alarm-clock, a spark-coil (a 3<t-in. coil is sufficient), an old bell, some spring- brass, binding-posts and wire, an ar- rangement can be made to obviate it.

The oil-stove, with the hood turned back to expose the burner, is shown in Fig. I. The wire may be ordinary 14- gage, asbestos-covered. The principal thing to be observed is that the distance from the wire A to the burner B is less than from the wire to the Hue C (which comes down and covers the burner); otherwise the. spark would jump from A to C, instead of through the wick to B. This distance is best determined by experiment. Over the wire A is a tin strip F, soldered to the tank to hold the wire in position. The connector

��E may be removed by loosening the connecting screws; this permits taking out the tank without disturbing the spark-wire. Grounded to the frame of the stove is a binding post D.

The alarm-clock is mounted on a small board, as shown in Fig. 2. Have the brass springs sufficiently heavy and far enough apart to permit the key, when turning, to be held by the bend at the top of the spring. The important part of the mechanism is the relay, which turns off the current when the stove is lighted. A buzzer or an old door-bell is shown at A, Fig. 3, with the hook B soldered on to the end of the armature. A piece of sheet metal C is bent snugly around the screw H, which has a shoul- der filed in it to prevent C from lying on the board. A piece of brass, D, is bent as shown, with a hole drilled for the screw E, which adjusts the tension of D on C. The spring F tends to pull C to the stop G out from under the spring D. The wiring is shown by dotted lines.

The action is as follows: The magnet A draws the armature B to its core. This releases the spring C, which slides slowly (its movement is regulated by the screw E) out from under spring /-', causing a sliding contact of a few

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Wiring diagram and connections (Fig. 4) to an alarm-clock for lighting an oil-stove

seconds' duration, which ends in discon- necting the primary circuit. Dampening the movement of the spring gives the spark time enough to to ignite (he cold oil. — .XRTiitR F. Stilson.

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