Lectures on select subjects in mechanics, hydrostatics, hydraulics, pneumatics, and optics, with the use of the globes, the art of dialing, and the calculation of the mean times of new and full moons and eclipses / [James Ferguson].
- James Ferguson
- Date:
- 1790
Licence: Public Domain Mark
Credit: Lectures on select subjects in mechanics, hydrostatics, hydraulics, pneumatics, and optics, with the use of the globes, the art of dialing, and the calculation of the mean times of new and full moons and eclipses / [James Ferguson]. Source: Wellcome Collection.
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![bodies, they cannot be brouglit to touch oné another. e pafivene/s; by which it always endeavours to continue in the ftate that it is in, whether of reft or motion. And therefore, if one body contains does, it will have twice or thrite 4s much inac- tivity; that is, it will require twice or thrice as much force to give it an equal degree of motion, or to {top it after it hath been put into fuch a motion. That matter can never put itfelf into motion is allowed by all men. For they fee that a ftone, lying on the plane furface of the earth, never removes itfelf from that place, nor does any one imagine it ever can. But moft people are apt to believe that all matter has a propenfity to fall from a ftate of motion into a ftate of reft; becaufe they fee that if a ftone or a cannon-bal] be put into ever fo violent a motion, it foon {tops ; not confidering that this ftoppage is caufed, 1. By the gravity or weight of the body, which - finks it to the ground in fpite of the impulfe; | and, 2. By the refiftance of the air through which - it moves, and by which its velocity is retarded every. moment till it falls. A bowl moves but a fhort way upon a bowl- ing-ereen; becaufe the roughnefs and uneven- nefs of the graffy furface foon creates fri€tion fectly level, and covered with polifhed glafs, and the bow] were perfectly hard, round, and fmooth, it would go a great way farther; as it would have nothing but the air to refift it; if then the air were taken away, the bowl would go on without. any friction, and confequently without 9 : any](https://iiif.wellcomecollection.org/image/b28756587_0016.jp2/full/800%2C/0/default.jpg)
