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according afforded annual appear Aries ascertain astronomers attention axis bodies called cause celestial centre CHAPTER circle complete consequently considerable considered course darkness diameter direction discovered distance diurnal divide earth east eastern eclipse effect equal equator exactly extends from degree fall figure fixed stars four given globe greater greatest gree half happen heavens Hence horizon hundred latitude less letter light longitude lunar magnitude mean meridian miles minutes month moon moon's motion move nature never night nodes northern observed obvious occasioned opposite orbit parallel particular passes between degree performs period planets pole position Principal star produced readers remain remarked respect result rises rotation round rule seasons seems setting seven shadow side signs situated solar southern hemisphere space sun's supposed termed third thousand tides tion true turn twelve western wind
Página 13 - Amid the radiant orbs, That more than deck, that animate the sky, The life-infusing suns of other worlds ; Lo ! from the dread immensity of space Returning, with accelerated course, The rushing comet to the Sun descends ; And as he sinks below the shading earth, With awful train projected o'er the Heavens, The guilty nations tremble.
Página 100 - For I perceived that, if Light was propagated in Time, the apparent Place of a fixed Object would not be the same when ' the Eye is at Rest, as when it is moving in any other Direction, than that of the Line passing through the Eye and the Object ; and that, when the Eye is moving in different Directions, the apparent Place of the Object would be different.
Página 99 - March, 1726, the star was found to be 20" more southwardly than at the time of the first observation. It now, indeed, seemed to have arrived at its utmost limit southward, because, in several trials made about this time, no sensible difference was observed in its situation. By the middle of April it appeared to be returning back again towards the north ; and about the beginning of June it passed at the same distance from the zenith as it had done in December when it was first observed. From the quick...
Página 100 - For I perceived that, if light was propagated in time, the apparent place of a fixed object would not be the same when the eye is at rest, as when it is moving in any other direction than that of the line passing through the eye and...
Página 79 - Eclipses of the sun are more frequent than those of the moon, because his ecliptic limits are greater ; and yet we have more visible eclipses of the moon than of the sun, which is owing to their being seen from all parts of the earth where the moon is above the horizon when the eclipse happens ; whilst those of the sun can only be observed on that small portion of the hemisphere, on which the moon's shadow falls. The greatest number of eclipses, of both luminaries, which can happen in a year, is...
Página 99 - I then endeavoured to find out the cause of them. I was already convinced that the apparent motion of the stars was not owing to a nutation of the earth's axis. The next thing that offered itself was an alteration in the direction of the plumb-line, with which the instrument was constantly rectified; but this upon trial proved insufficient. Then I considered what refraction might do; but here also nothing satisfactory occurred.