302 — TRANSLATIONS AND SELECTED ARTICLES. 
another; and the word strange, which J have used advisedly, will 
certainly appear natural to those who reflect that millions upon mil- 
lions of these rays can pass together through the eye of a needle 
without interfering with each other. 
The polarization of light has enabled astronomers to enrich their 
means of investigation, by the addition of some curious instruments 
which have already done good service, and among these is the one 
named the polariscope. 
If you look directly at the sun through one of these polariscopes, 
you will see two images of the same intensity and tint—both white. 
Suppose, now, that you look at the sun’s image reflectei! at the surface 
of water, or of a glass mirror. In the act of reflexion, the rays 
become polarized; the polariscope no longer gives two white and 
similar images, but on the contrary, they are tinted with most vivid 
colors, although their form does not undergo alteration. If the one 
is red, the other will be green; if the first is yellow, the second will 
have the violet tint, and so on—the two tints being always comple- 
mentary, as it is called, that is, capable of forming white light by their 
mixture. Whatever be the process by which natural light becomes 
polarized, the colors are exhibited in the two images of the polaris- 
cope, just as if we had been looking at light reflected from water or 
glass. The polariscope, then, furnishes a very simple ‘mode of dis- 
tinguishing polarized from natural light. 
It was for a long time thought that the light proceeding from any 
incandescent body reaches the eye in the condition of natural light, 
provided that in the passage it had not been partially reflected, 
or much refracted, but this proposition fails in certain cases. A 
member of the Academy has discovered that the light which pro- 
ceeds, under a sufficiently small angle, from the surface of an inean- 
descent body, whether liquid or solid, and even when it is not 
polished, offers evident traces of polarization, @o that by passing 
into the polariscope it becomes decomposed into two colored portions 
(faisceauz colores). The light which proceeds from a gaseous sub- 
stance in the act of burning (as the gas which to-day illuminates our 
streets and shops) is, on the contrary, always in its natural state, 
whatever may have been the angle of emission.* 
* The incandescent bodies of which the lizht emitted under different angles has been 
ezamined with the polariscope, are the following: solids, forged iron and platinum; dquids, 
melted iron and fused ¢lass. According to these experiments, some one may say, you have ® 
right to affirm that the sun is neither melted iron nor fused glass, but what authorises you to 
