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The second class includes about three-eighths of his stars, including Capella, Pollux, and Arcturus. These stars give a spectrum like that of our sun, and appear yellowish to the eye. The spectrum has fluted bands shaded from blue to red, and sharply defined at the more refrangible edge.
The singular fact was, however, elicited that this almost evanescent spectrum is made up of two superposed spectra, one due to reflection, the other, with a maximum far down in the infra-red, to radiation. The corresponding temperature of the moon's sunlit surface Professor Langley considers to be about that of freezing water.
The strangers wore no clothing, and their smooth skins shone a dark, livid, utterly indescribable color in the peculiar, unearthly, yellowish-bluish-green glare of the light. Green their skins undoubtedly were, but not any shade of green visible in the Earthly spectrum. The "whites" of their eyes were a light yellowish-green.
If a star is approaching, its spectral lines are shifted toward the violet end of the spectrum by an amount depending upon the velocity of approach; if it is receding, the lines are correspondingly shifted toward the red end. Spectroscopic observation, then, combined with micrometric measurements of the cross motion, enables us to detect the real movement of the star in space.
And he would maintain, with endless ingenuity, confidence and persistence, his fallacious spectrum to be a real image. However, it was sure to come all right in the end. Whatever real excellence he might misknow, you had but to let it stand before him, soliciting new examination from him: none surer than he to recognize it at last, and to pay it all his dues, with the arrears and interest on them.
Hence, when, the reverse spectrum of any colour became faint, it was wonderfully revived by admitting more light through the eyelids, by removing the hand from before them: and hence, on covering the closed eyelids, the spectrum would often cease for a time, till the retina became sensible to the stimulus of the smaller quantity of light, and then it recurred.
He also found that, if he used a limelight instead of the sunlight and passed it through the flame with salt, the spectrum showed the D line black; or the vapour of sodium absorbs the same light that it radiates. This proved to him the existence of sodium in the sun's atmosphere. Iron, calcium, and other elements were soon detected in the same way.
They extend for two octaves above the violet of the spectrum and are too short to affect the eye as light, although they affect photographic plates. They are the friend of man when he uses them in moderation as Finsen did in the famous blue light treatment. But they tolerate no familiarity. To let them =20 particularly the shorter of the rays enter the eye is to invite trouble.
Humphrys with special apparatus, the coronal spectrum, continuous and linear, impressed itself more extensively in the ultra-violet than on any previous occasion; and Dr. Mitchell succeeded in photographing the reversing layer by means of a grating spectroscope. Finally, Mrs.
After a period experiments were continued at the Brooklyn Navy Yard. In 1915 Commander J. O. Fisher, U.S.N., painted the periscope of his submarine the K-6 with the colors of the spectrum. Mr. Mackay got in touch with this officer and explained the work he had done with Lieutenant Whiting.
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