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Updated: June 19, 2025
The difficulty is that these stars appear to us so faint individually, that the investigation of their spectra is still beyond the powers of our instruments.
The meridian or evening light makes a difference in the colours of some spectra; for as the sun descends, the red rays, which are less refrangible by the convex atmosphere, abound in great quantity.
On talismans some curious natural ones, etc. On the medicinal powers attributed to music by the ancients. Presages, prodigies, presentiments, etc. Phenomena of meteors, optic delusions, spectra, etc. Elucidation of some ancient prodigies. Magical pretensions of certain herbs, etc. The practice of Obeah, or negro witchcraft charms their knowledge of vegetable poison secret poisoning.
Thus when a child revolves some minute on one foot, the spectra of the ambient objects appear to circulate round him some time after he falls upon the ground. Thus the palpitation of the heart continues some time after the object of fear, which occasioned it, is removed.
Yet after frequently revolving, both with my eyes closed, and with them open, and attending to the spectra remaining in them, by shading the light from my eyelids more or less with my hand, I at length ceased to have the idea of going forward, after I stopped with my eyes closed; and saw changing spectra in my eyes, which seemed to move, as it were, over the field of vision; till at length, by repeated trials on sunny days, I persuaded myself, on opening my eyes, after revolving some time, on a shelf of gilded books in my library, that I could perceive the spectra in my eyes move forwards over one or two of the books, like the vapours in the air of a summer's day; and could so far undeceive myself, as to perceive the books to stand still.
As is usual in such an investigation, a great variety of difficulties have been encountered, and the most important of them have now been overcome. Faint Stellar Spectra. The 28 inch reflector will be used for the study of the spectra of the faint stars, and also for the fainter portions near the ends of the spectra of the brighter stars.
Behind this gaseous spectrum was found a faint continuous spectrum ascribed to the nucleus, which apparently both reflects the sunlight and gives forth the light of a glowing solid or liquid. Subsequently sodium and iron lines were found in cometary spectra.
It has been suggested that sun-spots are indications of the beginning of a process in the sun which will be intensified until it falls into the state of such a star as Mira. Stars very far advanced in evolution, without showing variability, also exhibit similar spectra; so that there is much reason for regarding sunspots as emblems of advancing age.
Since 1892 one Nova after another has shown a spectrum as described above, like a meteor rushing towards us and leaving a train behind, for this seems to be the obvious meaning of the spectra. The same may be said of the brilliant Nova Persei, brighter at its best than Capella, and discovered also by Dr. Anderson on February 22nd, 1901.
For they were closely paralleled by some earlier experiments of Wiedemann, in which the gaseous spectra of vacuum tubes were at once effaced on the introduction of metallic vapours. It seemed as if the metal had no sooner been rendered volatile by heat, than it usurped the entire office of carrying the discharge, the resulting light being thus exclusively of its production.
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