Chap. i. PHILOSOPHY.

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I z. Farther, if this our globe of earth swam in a fluidof equal density with the earth it self, that is, in a fluid moredense than water; all bodies put in motion here upon theearth’s surface must suffer a great resistance from it; whereas, by Sir I s a a c Newton’s experiments mentioned in thepreceding chapter, bodies, that fell perpendicularly downthrough the air, felt about ^ part only of the resistance,which bodies suffered that fell in like manner through water.

14.. Sir Is a ac Newton applies these experiments yetfarther, and examines by them the general question concern-ing the absolute plenitude of space. According to the Aristote-lians, all space was full without any the least vacuities whate-ver. DesCartes embraced the fame opinion, and thereforesupposed a subtile fluid matter, which should pervade all bo-dies, and adequately sill up their pores. The Atomical philo-sophers, who suppose all bodies both fluid and solid to be com-posed of very minute but solid atoms, assert that no fluid, howsubtile soever the particles or atoms whereof it is composedshould be, can ever cause an absolute plenitude ; because itis impossible that any body can pass through the fluid with-out putting the particles of it into such a motion, as to sepa-rate them, at least in part, from one another, and so perpetu-ally to cause small vacuities; by which these Atomists endea-vour to prove, that a vacuum, or some space empty of allmatter, is absolutely necessary to be in nature. Sir I s a a cNewton objects against the silling of space with such a sub-tile fluid, that all bodies in motion must be immeasurably re-

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