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

  • Walker, A. (Adam), 1730 or 1731-1821.
Date:
[1790]
Catalogue details

Licence: Public Domain Mark

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

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    t 78 ] . , , » The earth’s roundnefs is no more affie&ed by the largeft mountains, than the roundnefs of a common globe is by a few grains of duff thrown upon it ; for they bear no greater proportion to its bulk. It is 7,970 miles in diameter : Near 100 millions of miles, from the fun : Moves round him in 365 days 5 hours and 49 mi¬ nutes, at the rate of 60,000 miles an hour ; and turns round upon its axis every 24 hours, from weft to eaft, which makes all the heavenly bodies feem to turn round the contrary way, or from eaft to weft. The particles of which the earth is compofed would fly into confufion, if not held together in the form of a globe by th z pozver of gravitation* ?Tis this power which gives weight to all bodies, or that tendency they have to¬ wards the centre of the earth. Hence the general top of the earth becomes its whole furface, and the general bottom its centre. The Antipodes are therefore as much on the top as we. But as the parts of the earth are loofe, the violent mdtion it has on its axis will in fome degree overpower even the force of gravity, and accumu¬ late .more matter round the Equator, becaufe the centri¬ fugal force is greateft there ; hence the true figure of the earth is an oblate fpheroidy or like an orange, 35 miles more in diameter at the equator than at the poles. This was proved by an adlual menfuration, and is explained by the whirling rings. This oblate figure proves its diurnal motion ; if it was at reft it would be neceftariiy a perfedf fphere. We per¬ ceive not this motion, becaufe the ah\ in which we live, partaking of the general gravitation, is carried round along with the earth. When a ftiip turns round, if we look out at the cabin windows, we believe ourfelves at reft, and the neighbouring country turning round us ; —we are deceived in like manner in the motion of the earth. L Where