. Automotive industries . ad surface at a reasonable distanceahead of the car, but does not rise to a sufficient heightto reach the eyes of the approaching pedestrian or vehicledriver. Use of the dispersion principle does not seemlogical, for we first place behind and around the luminoussource a carefully made reflector to gather the rays intoa parallel beam and then place in front of the source alens which breaks the beam up again before it has accom-plished any useful purpose. The eyes of other users of thehighway are always above the level of the headlights andthe most logical plan seems to
. Automotive industries . ad surface at a reasonable distanceahead of the car, but does not rise to a sufficient heightto reach the eyes of the approaching pedestrian or vehicledriver. Use of the dispersion principle does not seemlogical, for we first place behind and around the luminoussource a carefully made reflector to gather the rays intoa parallel beam and then place in front of the source alens which breaks the beam up again before it has accom-plished any useful purpose. The eyes of other users of thehighway are always above the level of the headlights andthe most logical plan seems to be to direct all the raysfrom the source downwardly. This can be done by useof lenses of prismatic form; it can also be done by givingthe reflector a suitable shape, and this is perhaps thesimplest method. C. W. and C. H. Crockett have developed a reflectorwhich permits of this desirable control of the beam oflight. This reflector is in the form of one smooth con-tinuous surface, but within the concavity of the reflector. there is a space, in which the source of light may be placed,such that, when the light source is wholly in the space, allof the light falling on the reflector will be reflected eitherhorizontally or in a downward direction. The surface of the reflector is generated by revolving,about its horizontal axis, a parabolic arc whose parameie*
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectaeronautics, bookyear
