Analysis of a course of lectures on natural and experimental philosophy : viz. 1. Properties of matter, 2. Mechanics, 3. Chemistry, 4 and 5. Pneumatics, 6. Hydrostatics, 7. Electricity, 8. Electricity [sic], 9. Optics, 10. Use of the globes, &c., 11 and 12. Astronomy / by A. Walker.

  • Walker, A. (Adam), 1730 or 1731-1821.
Date:
[1795?]
Catalogue details

Licence: Public Domain Mark

Credit: Analysis of a course of lectures on natural and experimental philosophy : viz. 1. Properties of matter, 2. Mechanics, 3. Chemistry, 4 and 5. Pneumatics, 6. Hydrostatics, 7. Electricity, 8. Electricity [sic], 9. Optics, 10. Use of the globes, &c., 11 and 12. Astronomy / by A. Walker. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    LECTURE XII. ASTRO NOMT. 'T^HE planets are retained in their orbits by the power of gravity;—but as the fun is by far the largeft body In our fyllenri, if no other power a6ted on them they would be drawn down tp the fun. All bodies therefore that move pulfe at its creation, fo that between one power drawing to the centre, and another ailing perpendicular to it, the planets are impelled in eliptic orbits round the fun, as a pebble tied to a mill -ftone, and thrown from the hand, would revolve round the mill-ftcJne. Ati idea of this is given by a ball impelled fvngly in a fquare in two diredlions, one perpendicular to the other; when they both a6l they give the diagonal of the fquare, &c. Our fyftem mull be conceived as within the concave fphere feeming to be formed by the fixedJlars, and the /«« as near the centre of it, an huge globe of fitc> near a mil- lion of miles in diameter, and near too millions of miles from the earth, according to calculations made from thcj tranlits of Venus.—He turns round on his axis in 25 days] and 8 hours, as mav be feen by fpots on his face ; and wasl no doubt intended to give light, heat, and vegetation to] the fix primary and ten fecondary planets which revolv<^ round him. \ ' fuppofe the Almighty gave each planet this kind of im in turves, as the planets do round the fun, mull be adled upon by two principles \ and motion being reililineal, vte