Man's physical universe

xanabras

POLARIZED LIGHT 425

arranged at an angle of 45° to the ground in one proposed system of

eliminating automobile-headlight glare.

The headlights of each car are fitted with Polaroid lenses with their

slots parallel with the visor slots, that is, at exactly the same angle.

The light from the headlights strikes the road and is reflected back

through the Polaroid visor to the driver,

who gets the benefit of his own headlights

because the visor and headlight slots

are

parallel.

When two cars thus equipped meet each

other, neither driver sees the direct light of

the approaching headlights because the

slanted slots of the Polaroid are crossed at

right angles inasmuch as the cars are facing

each other.

Light from the approaching

car cannot get through the visors, and glare

is therefore eliminated.


Light May Be Polarized by Scattering.

When light is reflected from particles

such as the drops of moisture in the clouds,

there is

no polarization; but when light is

Fig. 189. Polaroid visors

used to eliminate headlight

glare. (Courtesy of The

Polaroid Corporation.)

reflected from much smaller particles, such as dust and smoke particles,

the light is scattered, and a bluish tinge typical of desert scenery appears.

These small particles scatter short waves better than long

ones; the blue waves are on the shorter-wave-length end of the visible

Fig. 190. Unretouched photographs. Left, ordinary headlights. Right,

Polaroid headlights through a Polaroid visor (Courtesy of The Polaroid

Corporation.)

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