Elements of physics, or, Natural philosophy, general and medical : explained independently of technical mathematics, and containing new disquisitions and practical suggestions.

  • Arnott, Neil, 1788-1874
Date:
1827
Catalogue details

Licence: Public Domain Mark

Credit: Elements of physics, or, Natural philosophy, general and medical : explained independently of technical mathematics, and containing new disquisitions and practical suggestions. Source: Wellcome Collection.

    140/688 (page 90)
    There may really be such revolving masses above our atmosphere, although invisible to us owing to their smallness. It has been supposed by some, but untenably, that the meteoric stones, which fall to earth every now and then, come from such bodies, or are the entire masses which in some way have become entangled in our atmosphere, and have fallen in consequence. The four little planets discovered lately between Mars and Jupiter, are not larger than a six-thousandth part of our earth. Repulsion produces accelerated, retarded, and bent motions, like attraction, but it acts only at minute distances. Attraction draws from the sun, or from the very limits of the universe; while repulsion acts, for instance, between the adjoining atoms of an elas¬ tic fluid. Yet repulsion plays a part in the economy of nature, not at all inferior to its sister attraction. We have already seen, when considering the con¬ stitution of masses in section first, that repulsion keeps the atoms of all bodies from reaching com¬ plete contact ; that with increase of temperature, it causes these atoms to separate and to form a liquid, or even an air; that it operates around all masses as if it were a film or covering, preventing their mutual cohesion, &c. &c. Accelerated motion from repulsion, is seen when the atoms of gunpowder explode and propel the bullet from the bottom of a piece to the muzzle with such rapidly increasing velocity. The strength of this repulsion of gunpowder is so much stronger than the strength of general attraction, that its