Evening Republican, Volume 18, Number 7, Rensselaer, Jasper County, 8 January 1914 — The Pressure of Light. [ARTICLE]

The Pressure of Light.

The idea that the waves of light produce a mechanical push or pressure is not new, having been advanced years ago by Clerk Maxwell, who could offer only a theoretical f>roof. Later Lebedew, of Moscow, made an experimental demonstration of the pressure of light He employed a radiometer resembling the familiar Crookes radiometers with their revolving vanes, but used a larger and more completely exhausted bulb, from which the heating effect that Is the principal agent, to moving the Crookes vanes .was excluded. When the light falls upon the vanes they are driven before It and the Intensity of the pressure thus revealed comes within ten per cent of that calculated by Maxwell. The effect is independent of the color of the light, and directly proportional to Its energy.—New t York Herald.

There are arguments for and against the powerful headlights 4n general use on locomotives, and in order to weigh the matter carefully, the Indiana Railroad Commission cotfduoted an elaborate Investigation of the matter. The relatlv# efficiency of oil and electric lamps was Inquired into and also the effect of opposing headlights, the distance at which obstacles on the track may be detected and also the: effect of observing signals. The conclusion of the commission on this subject will be of great interest and importance. ' The smallest metal coin in circular tion is the Potuguese 3-reis piece, worth HOOth of S cent.