Man's physical universe

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ENERGY MAY BE PROPAGATED BY VIBRATIONS

High-voltage fluorescent tubing known commercially as "zeon"

(the N of Neon becomes the Z of Zeon when tipped on its side) lights

are similar to neon lights in

that they use long tubes and high-voltage

circuits, but they differ from neon lights in that the tubes are coated

inside with fluorescent materials. Both neon and zeon lights generate

ultraviolet radiations, but these radiations are absorbed by the glass in

neon lights without producing useful illumination, while the fluorescent

powders in zeon lights convert the ultraviolet radiations into visible

light. Any desired hue can be obtained with zeon lights, while the

choice is scant with neon lights.

Fluorescent Lamps Are Low-voltage Lamps Which Are Finding Widespread

Adoption.

The fluorescent lamp is a long tube coated inside with a fluorescent

material. The tube contains a small amount of mercury, which sets

up a mercury arc when electricity is passed through the tube. This

mercury arc produces ultraviolet radiations, which energize the

fluorescent materials, causing them to give off visible light.

In addition to the trace of mercury, there is a small amount of argon

gas at low pressure.

The argon serves as a starter to conduct the current

until the tube gets warm enough for the mercury vapor to do so.

Fluorescent lamps produce a stroboscopic effect when an object is

moved rapidly in their light because these lamps are operated by

alternating currents which cause the light to go on and off

120 times

a second. It is true that incandescent lamps are likewise usually

operated by alternating current, but in this case the light is produced

by a hot filament which remains incandescent between the electrical

impulses and thus gives an almost continuous light. Two fluorescent

lamps may be operated with certain auxiliary equipment in such a way

that one glow^s while the other one does not,

thus yielding a nearly

continuous light.

The flicker in fluorescent lamps is not noticed except when their

light falls upon moving objects because the phosphorescence tends to

keep the light fairly continuous. The discovery of a really good phosphorescent

material would greatly reduce the stroboscopic effect of

fluorescent lamps.

Fluorescent lamps are more expensive to install than ordinary

incandescent lamps because auxiliary control apparatus is required.

Inasmuch as the fluorescent lamp operates on a relatively low^-voltage

(110 volts) circuit, it must have its electrodes heated for starting. An

automatic switch closes the electric heating circuit when the electricity

is first turned on and opens the circuit as soon as the lartip begins to

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