LUXFER PRISMS AS LIGHT TRANSMITTERS

While some scientists have been busy with new inventions for the production of improved light from electricity and gas, others have given their attention to the more effective use of the light which is free to all, that of the sun, which is the ultimate source of all light.

HOW THE PRISM ACTS. Showing ray of light from above, deflected to a horizontal course as it passes through the glass.

The Luxfer prism, invented by a Canadian investigator of the phenomena of light, J. G. Pennycuick, is admittedly one of the most noteworthy of contributions to practical optics. Luxfer prisms are sheets of crystal glass having a smooth outer surface, and an inner surface divided into a series of small, accurately formed prisms. They can be united into plates of any size, to fit any window sash.
The rays of light from without, that strike the smooth surface, penetrate it as they do any other glass. The prisms on the opposite surface, however, are set at such an angle that the light passing through them is refracted to a horizontal direction, and thus illuminates the room much farther from the window than is the case with ordinary, plane-surfaced glass. The dark corners are lighted, the gas and electric light bills are reduced, and all this without a meter to continually register the savings and bring in a charge for it.
These prisms and their modified forms are applied to use in a multitude of ways. Large stores have them placed in the transom frames above the front windows, so that the rear of the long rooms may receive ample light. The same prisms placed like an awning in front of windows in a narrow, shaded street, gather the scanty light from above and deflect it into the building so equipped.

LUXFER PRISMS IN USE.
Illumination in a basement salesroom by means of prisms in the sidewalk.
Sidewalks made of Luxfer prisms receive the direct light from the sky on the upper face, and turn or refract it into the basement of the building adjoining. It is said that more than five thousand prominent buildings throughout the United States installed Luxfer prisms within the first five years of their manufacture. This is noteworthy evidence of the fact that new inventions that are of genuine value are sure to find welcome.