An epitome of astronomy, with the new discoveries: including an account of the eidouranion, or transparent orrery / (invented by A. Walker) as lectured upon by his son, W. Walker.

  • Adam Walker
Date:
1800
Catalogue details

Licence: Public Domain Mark

Credit: An epitome of astronomy, with the new discoveries: including an account of the eidouranion, or transparent orrery / (invented by A. Walker) as lectured upon by his son, W. Walker. Source: Wellcome Collection.

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    cumstance truly astonishing, to see in calm weather, and under a serene sky, the violent agitation of the great fluid mass of the ocean, whose waves roll against the shore with so grand impetuosity.—This spectacle invites to reflection, and rouses a desire to penetrate in¬ to its cause : hence the Earth’s three-fold motion appears in this scene that, on its axis, to produce day and night: that, round the Sun, to produce the year and our seasons ; and that, round the centre of gravity with the Moon, to produce spring and neap tides, by their combined and opposite influences. The Moon is so near the Earth (240,000 miles at a medium) in comparison of the Sun (near 100 millions of miles) that the Moon’s attrac¬ tion on the waters of the ocean and on the air of our atmosphere (for there are tides in both) is to that of the Sun as ten is to three. So at the change of the Moon, the attraction of the Sun and Moon being in the same di¬ rection, a power of thirteen influences the sea, and we have spring tides; but at the quarters of the Moon, the two luminaries counteract the attractions of each other, so the
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