Mechanism of the HeavensJ. Murray, 1831 - 621 pages |
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Page xii
... very small inclination to the plane of the ecliptic in which the earth moves ; and on that account , astronomers refer their motions to it at a given epoch as a known and fixed position . The paths xii PRELIMINARY DISSERTATION .
... very small inclination to the plane of the ecliptic in which the earth moves ; and on that account , astronomers refer their motions to it at a given epoch as a known and fixed position . The paths xii PRELIMINARY DISSERTATION .
Page xiii
Mary Somerville. epoch as a known and fixed position . The paths of the planets , when their mutual disturbances are omitted , are ellipses nearly approaching to circles , whose planes , slightly inclined to the ecliptic , cut it in ...
Mary Somerville. epoch as a known and fixed position . The paths of the planets , when their mutual disturbances are omitted , are ellipses nearly approaching to circles , whose planes , slightly inclined to the ecliptic , cut it in ...
Page xv
... epoch for the convenience of astronomical computation , is subject to a minute secular variation of 52 ′′ .109 , occasioned by the reciprocal action of the planets ; but as this is also periodical , the terrestrial equator , which is ...
... epoch for the convenience of astronomical computation , is subject to a minute secular variation of 52 ′′ .109 , occasioned by the reciprocal action of the planets ; but as this is also periodical , the terrestrial equator , which is ...
Page xxxix
... epoch , the heat of the summers must have been very great , though possibly compensated by the rigour of the winters ; at all events , none of these changes affect the length of the day . It appears from the marine shells found on the ...
... epoch , the heat of the summers must have been very great , though possibly compensated by the rigour of the winters ; at all events , none of these changes affect the length of the day . It appears from the marine shells found on the ...
Page xlvi
... epoch , and that the vernal equinox of that year should be the first day of the first year . The variations in the positions of the solar ellipse occasion corresponding changes in the length of the seasons . In its present position ...
... epoch , and that the vernal equinox of that year should be the first day of the first year . The variations in the positions of the solar ellipse occasion corresponding changes in the length of the seasons . In its present position ...
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Common terms and phrases
action angle appears arising assumed attraction axes axis becomes bodies cause centre of gravity changes co-ordinates coefficients computed consequently constant contain curve depending described determined differential direction distance disturbing earth eccentricity ecliptic effect elements epoch equal equation expression fixed fluid force functions give given greater hence inclination increase inequalities integral Jupiter Jupiter's known latitude longitude mass mean motion moon move nearly nodes observation obtained omitted orbit parallax particle periodic planets position preceding principal produce quantities radius ratio regard represented result revolve rotation satellites Saturn secular sine space square substituted supposed surface theory third tion true values variation varies vector velocity whence whole zero
Popular passages
Page xviii - ... that the mean longitude of the first satellite, minus three times that of the second, plus twice that of the third, is always equal to two right angles.
Page vii - His works, but trace, with precision, the operation of His laws, use the globe he inhabits as a base wherewith to measure the magnitude and distance of the sun and planets, and make the diameter of the earth's orbit the first step of a scale by which he may ascend to the starry firmament. Such pursuits, while they ennoble the mind, at the same time inculcate humility, by showing that there is a barrier which no energy, mental or physical, can ever enable us to pass: that, however profoundly we may...
Page xv - That day, as other solemn days, they spent In song and dance about the sacred hill ; Mystical dance, which yonder starry sphere Of planets, and of fix'd, in all her wheels Resembles nearest, mazes intricate, Eccentric, intervolved, yet regular Then most, when most irregular they seem ; And in their motions harmony divine So smooths her charming tones, that God's own ear Listens delighted.
Page xlix - An account of experiments for determining the length of the pendulum vibrating seconds in the latitude of London.
Page lxiv - Jupiter ; it then gradually diminished in splendor, and having exhibited all the variety of tints that indicate the changes of combustion, vanished sixteen months after its discovery, without altering its position. It is impossible to imagine anything more tremendous than a conflagration that could be visible at such a distance.
Page xiv - But, in the midst of all these vicissitudes, the length of the major axes and the mean motions of the planets remain permanently independent of secular changes. They are so connected by Kepler's law, of the squares of the periodic times being proportional to the cubes of the mean distances of the planets from the sun, that one cannot vary without affecting the other.
Page lxix - If the attraction of the sun for the огпtre of the earth, and of the hemisphere diametrically opposite to him, were diminished by a difficulty in penetrating the interposed matter, the tides would be more obviously affected. Its attraction is the same also, whatever the substances of the celestial bodies may be; for if the action of...
Page vi - is to inspire the love of truth, of wisdom, of beauty — especially of goodness, the highest beauty — and of that supreme and eternal Mind, which contains all truth and wisdom, all beauty and goodness. By the love or delightful contemplation and pursuit of these transcendent aims, for their own sake only, the mind of man is raised from low and perishable objects, and prepared for those high destinies which are appointed for all those who are capable of them.
Page xii - ... depends upon the velocity with which they were first propelled in space. Had that velocity been such as to make the planets move in orbits of unstable equilibrium, their mutual attractions might have changed them into parabolas, or even hyperbolas, so that the earth and planets might, ages ago, have been sweeping far from our sun through the abyss of space.
Page xxxvi - ... the waters back to their sources ; and thus again by removing matter to a greater distance from the centre, destroy the velocity generated by its previous approach ; so that the descent of the rivers does not affect the earth's rotation.
Bibliographic information
| Title | Mechanism of the Heavens |
| Author | Mary Somerville |
| Publisher | J. Murray, 1831 |
| Original from | Harvard University |
| Digitized | 17 Nov 2007 |
| Length | 621 pages |
| Export Citation | BiBTeX EndNote RefMan |