Page:The Mathematical Principles of Natural Philosophy - 1729 - Volume 1.djvu/63

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Rojectiles perevere in their motions, o far as they are not retarded by the reitance of the air, or impelled downwards by the force of gravity. A top, whoe parts by their coheion are perpetually drawn aide from rectilinear motions, does not ceae its rotation, otherwie than as it is retarded by the air. The greater bodies of the planets and comets, meeting with les reitance in more free paces, preerve the motions both progreive and circular for a much longer time.

If any force generates a motion, a double force will generate double the motion, a triple force triple the motion, whether that force be impre'd altogether and Rh