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Page 110
But the defects of colour remained, although their cause was unknown until
Newton carried out his experiments on dispersion and the solar spectrum. To
overcome the spherical aberration James Gregory," of Aberdeen and Edinburgh,
in 1663 ...
But the defects of colour remained, although their cause was unknown until
Newton carried out his experiments on dispersion and the solar spectrum. To
overcome the spherical aberration James Gregory," of Aberdeen and Edinburgh,
in 1663 ...
Page 114
The number of colours forming images is so numerous as to form a continuous
spectrum on the wall with all the colours — red, orange, yellow, green, blue,
indigo, and violet. But Frauenhofer found with a narrow slit, well fo– cussed by
the lens ...
The number of colours forming images is so numerous as to form a continuous
spectrum on the wall with all the colours — red, orange, yellow, green, blue,
indigo, and violet. But Frauenhofer found with a narrow slit, well fo– cussed by
the lens ...
Page 115
If sodium or common salt be thrown on the colourless flame of a spirit lamp, it
gives it a yellow colour, and its spectrum is a bright yellow line agreeing in
position with line D of the solar spectrum. In 1832 Sir David Brewster found some
of the ...
If sodium or common salt be thrown on the colourless flame of a spirit lamp, it
gives it a yellow colour, and its spectrum is a bright yellow line agreeing in
position with line D of the solar spectrum. In 1832 Sir David Brewster found some
of the ...
Page 117
Thus, by comparing the spectrum of a star alongside a spectrum of hydrogen, we
may see all the lines, and be sure that there is hydrogen in the star; yet the lines
in the star-spectrum may be all slightly displaced to one side of the lines of the ...
Thus, by comparing the spectrum of a star alongside a spectrum of hydrogen, we
may see all the lines, and be sure that there is hydrogen in the star; yet the lines
in the star-spectrum may be all slightly displaced to one side of the lines of the ...
Page 130
By choosing another line of the spectrum instead of calcium K — for example, the
hydrogen line Ha – we obtain two photographs, one showing the appearance of
the calcium floculi, and the other of the hydrogen floculi, on the same part of the ...
By choosing another line of the spectrum instead of calcium K — for example, the
hydrogen line Ha – we obtain two photographs, one showing the appearance of
the calcium floculi, and the other of the hydrogen floculi, on the same part of the ...
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Common terms and phrases
accurate Airy ancient Astronomer Royal astronomical units bright calculations Cape catalogue centre century Chaldaeans Chinese comet Copernicus diameter discovered discovery earth Egyptian epicycles equatorial error excentric explain fact fixed stars Galileo Greenwich Halley heavenly bodies heavens heliometer Hipparchus History of Astronomy Huggins instruments JOHANNEs KEPLER John Herschel Jupiter Jupiter's Kepler Laplace Lick Observatory light line of apses line of sight lunar Mars mathematical mean distance measured ment Mercury meteor miles a second moon nebulae Newton º º observations Observatory orbit parallax period photographic physical planet planetary pole position predicted proper motion proved Ptolemy R. S. Phil records refractor retrograde retrograde motion revolving round ring rotation satellites Saturn seems showing Sir William Herschel Sirius solar eclipse solar system spectra spectroscope spectrum sphere spots stellar sun-spot supposed tables telescope theory tion Trans Tycho Brahe universal gravitation Uranus velocity Venus Verrier
Popular passages
Page 67 - that every particle of matter in the universe attracts every other particle, with a force whose direction is that of the line joining the two, and whose magnitude is directly as the product of their masses, and inversely as the square of their distances from each other.
Page 26 - So he sate and cunningly guided the craft with the helm, nor did sleep fall upon his eyelids, as he viewed the Pleiads and Bootes, that setteth late, and the Bear, which they likewise call the Wain, which turneth ever in one place, and keepeth watch upon Orion, and alone hath no part, in the baths of Ocean. This star, Calypso, the fair goddess, bade him to keep ever on the left as he traversed the deep.
Page 53 - The third, viz. that the squares of the periodic times are proportional to the cubes of the mean distances...
Page 79 - Wherefore if according to what we have already said it should return again about the year 1758, candid posterity will not refuse to acknowledge that this was first discovered by an Englishman.
Page 122 - ... They have not been regarded as so successful as his geometrical analysis of the observed phenomena. It is only just to add that he himself did not attach equal weight to them ; for in answer to objections urged by Lalande to his theory that the spots are depressions, Wilson wrote thus in 1783 : — ' Whether their first production and subsequent numberless changes depend upon the eructation of elastic vapours from below, or upon eddies or whirlpools commencing at the surface, or upon the dissolving...
Page 51 - He then said boldly that it was impossible that so good an observer as Tycho could be wrong by eight minutes* and added, " out of these eight minutes we will construct a new theory that will explain the motions of all the planets.