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 73
... nodes , or in one of the points where the or- bits intersect each other . Hence it is obvious , that ( as the moon may perform many revolu- tions round the earth , before a new or full moon takes place in one of these points , ) there ...
... nodes , or in one of the points where the or- bits intersect each other . Hence it is obvious , that ( as the moon may perform many revolu- tions round the earth , before a new or full moon takes place in one of these points , ) there ...
Página 74
... nodes but twice in a year ; and the moon's orbit contains 360 degrees , ( of which 17 , the limit of solar eclipses on either side of the nodes , and 12 the limit of lunar eclipses , are but small portions ) it is obvious that there ...
... nodes but twice in a year ; and the moon's orbit contains 360 degrees , ( of which 17 , the limit of solar eclipses on either side of the nodes , and 12 the limit of lunar eclipses , are but small portions ) it is obvious that there ...
Página 75
... node passing by the sun , as seen from the earth , there will be only 173 days before the descending node passes that lumi- nary : at whatever time of the year , therefore , we have eclipses about either of the nodes , we may expect to ...
... node passing by the sun , as seen from the earth , there will be only 173 days before the descending node passes that lumi- nary : at whatever time of the year , therefore , we have eclipses about either of the nodes , we may expect to ...
Página 76
... node , and begin to come in at the north pole of the earth , will go a little southerly at each return , till they go quite off the earth at the opposite pole ; and those which happen about the descending node , and begin to come in at ...
... node , and begin to come in at the north pole of the earth , will go a little southerly at each return , till they go quite off the earth at the opposite pole ; and those which happen about the descending node , and begin to come in at ...
Página 77
... node and the moon is at her mean distance , the point of her sha- dow will just reach the earth , and on the small spot where it falls the darkness can be only mo- mentary . A total eclipse of the sun may be justly considered as one of ...
... node and the moon is at her mean distance , the point of her sha- dow will just reach the earth , and on the small spot where it falls the darkness can be only mo- mentary . A total eclipse of the sun may be justly considered as one of ...
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.