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Monthly Notices of the Royal Astronomical Society, Volum 53
Royal Astronomical Society
Visualitzaciķ completa - 1893
angle aperture appeared Astronomer atmosphere August bodies bright calculated cause central centre close clouds colour comet compared complete considered contains continuous correction course dark described determined diameter direction disk distance ditto double Earth eclipse effect elements employed equal error give given glass Greenwich Huggins important inches increased interest Jupiter length less light limb lines longitude magnitude March marked Mars mass mean measures meteors micrometer minute Moon motion nearly Nebulæ night noted noticed November object object-glass observations Observatory obtained orbit passed period planet portion position possible present probably produced Professor referred remarkable Royal satellite Sciences seen separated side Society Solar spectra spectrum stars sufficient Sun's surface taken telescope tion train visible whole wires
Pāgina 168 - D of the solar spectrum with the double bright line constituting the spectrum of the spirit-lamp burning with salt. I remarked that there must be some physical connexion between two agencies presenting so marked a characteristic in common. He assented, and said he believed a mechanical explanation of the cause was to be had on some such principles as the following : — Vapour of sodium...
Pāgina 170 - All these facts are comprehended in the statement that in a constant temperature the absorption of a particle is equal to its radiation, and that for every description of light. It was also noticed that all coloured glasses ultimately lose their colour in the fire as they approach in temperature the coals around them, the explanation being, that while red glass, for instance, gives out a greenish light, it passes red light from the coals behind it, while it absorbs the green...
Pāgina 262 - Clusters (Cl.) are members of the Via Lactea, and are nearer to us than the average of its faint stars. 2. The Nebulae resolved and unresolved lie in general without the Via Lactea, which is therefore essentially stellar. 3. The visible universe is composed of systems, of which the Via Lactea, the two Nubecula, and the Nebulae, are the individuals, and which are themselves composed of stars (either simple, multiple, or in clusters) and of gaseous bodies of both regular and irregular outlines.
Pāgina 161 - The light of the star is compound, and has emanated from two different sources. Each light forms its own spectrum. In the instrument these spectra appear superposed. The principal spectrum is analogous to that of the sun, and is evidently formed by the light of an incandescent solid or liquid photosphere, which has suffered absorption by the vapours of an envelope cooler than itself. The second spectrum consists of a few bright lines, which indicate that the light by which it is formed was emitted...
Pāgina 179 - That these lines were not produced by the portion of the earth's atmosphere through which the light of Mars had passed, was shown by the absence of similar lines in the spectrum of the moon, which, at-the time of observation, had a smaller altitude than Mars.
Pāgina 250 - In order to attain a sufficient degree of approximation it is requisite to break up the orbit of the meteors into a considerable number of portions, for each of which the attractions of the elliptic rings corresponding to the several disturbing planets...
Pāgina 159 - This observation was sufficient to solve the long-agitated inquiry in reference to this object at least, and to show that it was not a group of stars, but a true nebula. A spectrum of this character, so far as our knowledge at present extends, can be produced only by light which has emanated from matter in the state of gas.
Pāgina 161 - There must be a photosphere of matter in the solid or liquid state emitting light of all refrangibilities. Surrounding this must exist also an atmosphere of cooler vapours, which give rise by absorption to the groups of dark lines. Besides this constitution, which it possesses in common with the sun and the stars, there must exist the source of the gaseous spectrum. That this is not produced by the faint nebulosity seen about the star is evident by the brightness of the lines, and the circumstance...
Pāgina 160 - ... was situated about the centre of the nebula. Now this nebula possesses a minute but bright nucleus. We learn from this observation that the matter of the nucleus is almost certainly not in a state of gas, as is the material of the surrounding nebula. It consists of opaque matter, which may exist in the form of an incandescent fog of solid or liquid particles.
Pāgina 169 - ... have its temperature raised by light from the source, of the precise quality in question. In the atmosphere around the sun, therefore, there must be present vapour of sodium, which, according to the mechanical explanation thus suggested, being particularly opake for light of that quality, prevents such of it as is emitted from the sun from penetrating to any considerable distance through the surrounding atmosphere.