The Sun: Ruler, Fire, Light, and Life of the Planetary System |
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Page 10
... angle on whose exact measurement the solution of this problem depends . But even when any one has pictured to himself the difficulty of determining the exact angle subtended by an inch disc at that distance , and how easily the angle ...
... angle on whose exact measurement the solution of this problem depends . But even when any one has pictured to himself the difficulty of determining the exact angle subtended by an inch disc at that distance , and how easily the angle ...
Page 14
... angle a м b . As a matter of fact , however , even this small angle has to be re- duced considerably , because from a or b , the Moon would be on the horizon , and the estimate of her posi- tion rendered unsatisfactory by atmospheric ...
... angle a м b . As a matter of fact , however , even this small angle has to be re- duced considerably , because from a or b , the Moon would be on the horizon , and the estimate of her posi- tion rendered unsatisfactory by atmospheric ...
Page 15
Richard Anthony Proctor. tion rendered unsatisfactory by atmospheric refraction . The angle a м b is about a degree and a quarter , and it affords a very satisfactory idea of the skill with which ancient astronomers employed their ...
Richard Anthony Proctor. tion rendered unsatisfactory by atmospheric refraction . The angle a м b is about a degree and a quarter , and it affords a very satisfactory idea of the skill with which ancient astronomers employed their ...
Page 16
... angle M E S as well as the right angle at M ' , and thus the shape of the tri- angle E M's is assigned , and with it the proportion of E s to E M ' , which is what we require . Let us pause to notice the ingenuity of this method . The ...
... angle M E S as well as the right angle at M ' , and thus the shape of the tri- angle E M's is assigned , and with it the proportion of E s to E M ' , which is what we require . Let us pause to notice the ingenuity of this method . The ...
Page 17
Richard Anthony Proctor. because the latter angle is 60 times as great as the former , and secondly , because the necessary observa- tions can be made at one terrestrial station . Ingenious as the plan was , however , it was totally ...
Richard Anthony Proctor. because the latter angle is 60 times as great as the former , and secondly , because the necessary observa- tions can be made at one terrestrial station . Ingenious as the plan was , however , it was totally ...
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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...