The Scientific Library; Or, Repository of Useful and Polite Literature: Comprising Astronomy, Geography, Mythology, Ancient History, Modern History, and Chronology ...S. Wood & Sons, 1818 |
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Página 1
... particular seasons was an object which they naturally wished to ascertain ; and though their first observations were few , and extremely limited , their importance was suffi- ciently obvious to stimulate to new and deeper researches ...
... particular seasons was an object which they naturally wished to ascertain ; and though their first observations were few , and extremely limited , their importance was suffi- ciently obvious to stimulate to new and deeper researches ...
Página 50
... particular alone is not sufficient to enable us to fix the exact situation of any place , either on sea or land . We may , indeed , discover the parallel under which it lies , and its distance from the equator ; but before we can fix ...
... particular alone is not sufficient to enable us to fix the exact situation of any place , either on sea or land . We may , indeed , discover the parallel under which it lies , and its distance from the equator ; but before we can fix ...
Página 51
... particular , for as the latitude of any given place is its meridional distance from the equator , so the longitude of that place is its equatorial distance from the first meridian . If a place be situated in the eastern hemis phere ...
... particular , for as the latitude of any given place is its meridional distance from the equator , so the longitude of that place is its equatorial distance from the first meridian . If a place be situated in the eastern hemis phere ...
Página 53
... particular place , we must observe the hour in that place , and also find what hour it is at some distant part : the latter we must have from some exact time- keeper , set to the time of some other place , or from an observation of the ...
... particular place , we must observe the hour in that place , and also find what hour it is at some distant part : the latter we must have from some exact time- keeper , set to the time of some other place , or from an observation of the ...
Página 54
... particular hours , which being previously calculated for the meridian of Greenwich , they may , by a careful calcula- tion from it , correct their computed longitude . If a true - going time - piece could be obtain ed , the ...
... particular hours , which being previously calculated for the meridian of Greenwich , they may , by a careful calcula- tion from it , correct their computed longitude . If a true - going time - piece could be obtain ed , the ...
Términos y frases comunes
aberration of light altitude annual revolution apparent motion appear Aries ascer ascertain astronomers called cause celestial centre circle comets computed consequently course darkness days and nights degree 15 degree 30 diameter discovered distance diurnal motion diurnal rotation divide Dominical letter earth earth's shadow east eastern side epact equa equal equator equinoctial equinox exactly extends from degree fixed stars full moon golden number gree half happen heavenly bodies heavens horizon isphere Julius Cæsar latitude less Libra light longitude luminary lunar lunar eclipses magni millions of miles minutes month moon's orbit nodes noon north or south north pole northern occasioned opposite parallel passes between degree phere planets Principal star quadrant Rectify the globe refraction satellites seasons second magnitude shadow falls situated solar eclipse south pole southern hemis southern hemisphere southern side sun and moon sun-dial sun's place supposed tides time-piece tion tude turn twelve western young readers
Pasajes populares
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.
Página 26 - ... if the earth's axis were perpendicular to the plane of its orbit, and the excessive variation which would result if the axis were nearly parallel to that plane.