The Sun: Ruler, Fire, Light, and Life of the Planetary System |
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Page 13
... favourable conditions , a skilful observer , though he must needs make some error in estimating his bearings ( for no instruments can be absolutely per- fect ) , would yet bring the estimated point relatively very near to 0 ; in other ...
... favourable conditions , a skilful observer , though he must needs make some error in estimating his bearings ( for no instruments can be absolutely per- fect ) , would yet bring the estimated point relatively very near to 0 ; in other ...
Page 21
... favourably situated , and that two observers , one at E and the other at E ' ( fig . 9 ) , This line is only introduced to explain the unsymmetrical aspect of the two paths ; to show , in fact , that these are intentionally eccentric ...
... favourably situated , and that two observers , one at E and the other at E ' ( fig . 9 ) , This line is only introduced to explain the unsymmetrical aspect of the two paths ; to show , in fact , that these are intentionally eccentric ...
Page 25
... favourable opportunities do not occur at short intervals . The figure shows the successive conjunction - lines of the Earth and Mars between the years 1856 and 1871. It is seen that only the conjunctions of 1860 and 1862 are favourable ...
... favourable opportunities do not occur at short intervals . The figure shows the successive conjunction - lines of the Earth and Mars between the years 1856 and 1871. It is seen that only the conjunctions of 1860 and 1862 are favourable ...
Page 26
... favourable for the purpose of astronomers than Mars . When the Earth and Mars are in conjunction as at E and M , fig . 8 , the sun is on the opposite side of the earth , and so Mars is seen on a dark sky ; but when Venus and the Earth ...
... favourable for the purpose of astronomers than Mars . When the Earth and Mars are in conjunction as at E and M , fig . 8 , the sun is on the opposite side of the earth , and so Mars is seen on a dark sky ; but when Venus and the Earth ...
Page 33
... favourably seen . For it must be remembered that a large part of the Earth is unfitted for the observer's purposes . We must not place our observers on the open sea , nor in regions where bad weather ordinarily prevails . And this ...
... favourably seen . For it must be remembered that a large part of the Earth is unfitted for the observer's purposes . We must not place our observers on the open sea , nor in regions where bad weather ordinarily prevails . And this ...
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Common terms and phrases
actual angle aperture aphelion appear astronomers battery of prisms body bright lines cause centre chromosphere clouds coloured consider corona corresponding dark lines deduced determining the Sun's diameter difficulty direction dispersion Earth eclipse effect error estimate exact fact faculæ favourable Fraunhofer greater Halley's method heat Herschel Hipparchus inferior conjunction Kirchhoff length less limb luminous Mars mass mean distance measure miles per second minute Moon Moon's motion node noticed observations orbit pass path peculiarity penumbra perihelion phenomena photosphere planets polariscopic portion present prism problem prominences proportion rays recognised red end regarded researches respecting rotation Secchi seen slit sodium solar light solar parallax solar physics solar prominences solar spectrum solar spots spectra spectroscopic analysis star stations Sun can control Sun-spots Sun's disc Sun's distance Sun's surface supposed telescope terrestrial tion transit transits of Venus vapours velocity Venus Venus's violet end visible
Popular passages
Page 403 - I have seen the wild stone-avalanches of the Alps, which smoke and thunder down the declivities with a vehemence almost sufficient to stun the observer. I have also seen snow-flakes descending so softly as not to hurt the fragile spangles of which they were composed ; yet to produce from aqueous vapour a quantity, which a child could carry, of that tender material, demands an exertion of energy competent to gather up the shattered blocks of the largest stone-avalanche I have ever seen, and pitch...
Page 117 - I obtained a tolerably bright solar spectrum, and brought a flame coloured by sodium vapour in front of the slit. I then saw the dark lines D change into bright ones.
Page 391 - The sun's rays are the ultimate source of almost every motion which takes place on the surface of the earth. By its heat are produced all winds, and those disturbances in the electric equilibrium of the atmosphere which give rise to the phenomena of lightning, and probably also to those of terrestrial magnetism and the aurora.
Page 193 - Herschel,' would come, on this view of the subject, to be assimilated to those regions on the Earth's surface in which, for the moment, hurricanes and tornadoes prevail — the upper stratum being temporarily carried downwards, displacing by its impetus the two strata of luminous matter beneath...
Page 411 - ... melt in air, — the flux of power is eternally the same. It rolls in music through the age^s, and all terrestrial energy, — the manifestations of life as well as the display of phenomena, are but the modulations of its rhythm.
Page 409 - Still, presented rightly to the mind, the discoveries and generalisations of modern science constitute a poem more sublime than has ever yet been addressed to the imagination. The natural philosopher of to-day may dwell amid conceptions which beggar those of Milton.
Page 410 - ... unable to detect a diminution of his store ; measured by our largest terrestrial standards, such a reservoir of power is infinite ; but it is our privilege to rise above these standards and to regard the sun himself as a speck in infinite extension — a mere drop in the universal sea. We analyze the space in which he is immersed, and which is the vehicle of his power.
Page 205 - By degrees, accounts began to pour in of great Auroras seen on the nights of those days ; not only in these latitudes, but at Rome ; in the West Indies ; on the tropics within 18° of the equator (where they hardly ever appear), nay, what is still more striking, in South America and in Australia ; where, at Melbourne, on the night of the 2d of September the greatest Aurora ever seen there made its appearance.
Page 183 - Hence he concludes that the sun has a very extensive atmosphere, which consists of elastic fluids that are more or less lucid and transparent ; and of which the lucid ones furnish us with light. This atmosphere, he...
Page 321 - The corona was far broader than that which I saw in 1842; roughly speaking, its breadth was little less than the moon's diameter ; but its outline was very irregular. I did not remark any beams projecting from it which deserved notice as much more conspicuous than the others ; but the whole was beamy, radiated in structure, and terminated (though very indefinitely) in a way which reminded me of the ornament frequently placed round a mariner's compass. Its colour was white...