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Updated: June 19, 2025
We will now go on to the third class of mnemonic error, which I have called the spectra of memory, where there is not simply a transformation of the past event, but a complete imaginative creation of it. This class of error corresponds, as I have observed, to an hallucination in the region of sense-perception.
The service which photography has rendered to astronomy can scarcely be overestimated, and these pioneers in the art were laying the foundations for its recent wonderful developments. He was the first to attempt to classify the stars according to their spectra, and invented a number of instruments of the greatest service in star photography.
And for the same reason, it is difficult to gain the reverse spectrum, where there is no lateral light to contribute to its formation. Thus, in looking through an opake tube on a yellow wall, and closing my eye, without admitting any lateral light, the spectra were all at first yellow; but at length changed into blue.
"I see what you mean," said Professor Gazen; "and, now I think of it, all the spectra we have seen belong to the group called 'metals of the alkalies and alkaline earths, which, of course, have distinctive properties." "At first, I should think the Martians would only try to attract our notice by striking spectra." "Lithium is the lightest metal known to us."
The association of stars with planetary nebulae, and the distribution of nebulae in the heavens, especially in relation to the Milky Way, are striking facts, which will certainly bear fruit when the time arrives for discarding vague speculations, and learning to read the true physical structure and history of the starry universe. Stellar Spectra.
A reproduction is given of photographed spectra of the four outermost planets, showing a great number of new lines and bands; intensification of hydrogen F. and C. lines; a steady increase of effects and as we pass from Jupiter and Saturn to Uranus, and a still greater increase in Neptune. Asteroids. The discovery of these new planets has been described.
It would appear, then, that all stars are suns with continuous spectra, and the classes are differentiated by the character of the absorbent vapours of their atmospheres. It is very likely that, after the chemists have taught us how to interpret all the varieties of spectrum, it will be possible to ascribe the different spectrum-classes to different stages in the life-history of every star.
At the same time, all the lines have been catalogued in the light of the sun and the brighter of the stars. Another method of obtaining spectra had long been known, by transmission through, or reflection from, a grating of equidistant lines ruled upon glass or metal.
A tank containing one of these materials is interposed and the spectra photographed through it. The stellar spectra will then be traversed by lines resulting from the absorption of the media thus interposed, and, after their wave lengths are once determined, they serve as a precise standard to which the stellar lines may be referred.
We see, then, how much uncertainty attaches to all autobiographical description of very early life. Modern science suggests another possible source of these distinct spectra of memory.
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