93 STANDARD ELECTRICAL DICTIONARY.

Buoy, Electric.

A buoy for use to indicate channels or dangers in harbors and elsewhere,

which carries an electric light, whose current is supplied by cable from

shore. It has been proposed to use glass tubes exhausted of air and

containing mercury, which, as moved by the waves, would produce a

luminous effect. A fifty-candle power incandescent lamp is an approved

source of light.

Burner, Electric Gas.

A gas burner arranged for the flame to be lighted by electricity. It

takes a great variety of forms. In some cases a pair of terminals are

arranged near the flame or a single terminal is placed near the metal

tip, the latter forming one of the terminals. The spark is generally

produced by an induction coil, or a spark coil. The gas may first be

turned on and the spark then passed. Sometimes the turning of the gas

cock of an individual burner makes and breaks a contact as it turns, and

thereby produces simultaneously with the turning on of the gas a spark

which lights it.

Another form is wholly automatic. A pair of electro-magnets are attached

below the base of the burner, one of which, when excited, turns on the

gas, and the other one when it is excited turns it off. At the same time

a spark is produced with the turning on of the gas so that it is

lighted. Thus, by use of a automatic burner, a distant gas burner can be

lighted by turning an electric switch. An out-door lamp may be lighted

from within a house.

The increasing use of electric incandescent lamps, lighted by the

turning of a switch, tends to displace electric gas burners. The latter

have been classified into a number of types depending on their

construction.

Burners are sometimes connected in series with leads from an induction

coil. Then the gas is turned on all at once, and a succession of sparks

passed until the gas is all lighted. The ignition is practically

instantaneous.

Button, Push.

A species of switch which is actuated by the pressure of a button. In

its normal position the button is pressed outwards by a spring, and the

circuit is open. When pressed inwards, it closes the circuit. When

released it springs backward and opens the circuit again.

They are principally used for ringing bells. If the latter are of the

automatic type, they ring as long as the button is pressed.

For door-bells and room-bells, the button often occupies the center of a

rosette of wood or bronze or other ornamental piece. Sometimes, as shown

in the cut, they are constructed for use on floors to be pressed by the

foot. The general principle of their construction is shown, although the

method of making the contact varies.

Synonym--Press Button.

Fig. 71. FLOOR PUSH BUTTON.

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