The Sun: Ruler, Fire, Light, and Life of the Planetary System |
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Page 7
... regarded as the very foundation of all our researches . For until we know the Sun's distance we can determine neither his bulk nor his weight ; and our views even as to his physical condition will be found to depend in an important ...
... regarded as the very foundation of all our researches . For until we know the Sun's distance we can determine neither his bulk nor his weight ; and our views even as to his physical condition will be found to depend in an important ...
Page 15
... regarded as wholly ineffective . Other methods , then , must be adopted . I proceed to consider two methods which suggested themselves to ancient astronomers . It is interesting to consider even those attempts which have failed ; for ...
... regarded as wholly ineffective . Other methods , then , must be adopted . I proceed to consider two methods which suggested themselves to ancient astronomers . It is interesting to consider even those attempts which have failed ; for ...
Page 22
... regarded as infinitely far off , so that M E is as a mere point at the centre of this sphere ; and therefore the arc mm ' , as estimated from the Earth , is precisely the same as though it were estimated from M , -or , in other words ...
... regarded as infinitely far off , so that M E is as a mere point at the centre of this sphere ; and therefore the arc mm ' , as estimated from the Earth , is precisely the same as though it were estimated from M , -or , in other words ...
Page 44
... regarded as the true moment of internal contact , or whether that is the true moment when the circular part of Venus's apparent outline , if FIG . 15 . 2 3 continued so as to form a complete circle , would just touch the Sun's outline ...
... regarded as the true moment of internal contact , or whether that is the true moment when the circular part of Venus's apparent outline , if FIG . 15 . 2 3 continued so as to form a complete circle , would just touch the Sun's outline ...
Page 48
... regarded with such confidence , since it needed but a brief examination of the basis on which Encke's result was founded , to see that no faith what- ever could be placed in three at least out of the five numerals in the expression 8 ...
... regarded with such confidence , since it needed but a brief examination of the basis on which Encke's result was founded , to see that no faith what- ever could be placed in three at least out of the five numerals in the expression 8 ...
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Common terms and phrases
angle aperture aphelion appearance astronomers atmosphere battery of prisms body bright lines cause centre chromosphere clouds coloured consider corona corresponding dark lines deduced determining the Sun's diameter direction dispersion Earth eclipse effect error estimate exact fact faculæ favourable Fraunhofer greater Halley's method heat Herschel Hipparchus hydrogen Kirchhoff length less limb luminous Mars mass matter mean distance measure miles per second minute Moon Moon's motion noticed observations orbit pass path peculiarity penumbra perihelion phenomena photosphere planets polariscope portion present prism problem prominences proportion rays recognised red end regarded remarkable researches respecting rotation Secchi seen Sir William Herschel slit sodium solar light solar parallax solar physics solar prominences solar spectrum solar spots spectra spectroscopic analysis star stations Sun can control Sun-spot 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 405 - 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 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 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 393 - 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 413 - ... melt in air, — the flux of power is eternally the same. It rolls in music through the ages, and all terrestrial energy, — the manifestations of life as well as the display of phenomena, are but the modulations of its rhythm.
Page 193 - Herschel,'wouldcome,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 412 - And still, notwithstanding this enormous drain in the lapse of human history, we are 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 analyse the space in which he is immersed, and which is the vehicle of his power.
Page 411 - 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 412 - To Nature nothing can be added ; from Nature nothing can be taken away ; the sum of her energies is constant, and the utmost man can do in the pursuit of physical truth, or in the...
Page 204 - It was impossible, on first witnessing an appearance so similar to a sudden conflagration, not to expect a considerable result in the way of alteration of the details of the group in which it occurred; and I was certainly surprised, on referring to the sketch which I had carefully and satisfactorily (and I may add fortunately) finished before the occurrence, at finding myself unable to recognize any change whatever as having taken place.