Page:The Mathematical Principles of Natural Philosophy - 1729 - Volume 1.djvu/15

Rh. ''chiefly converant in the moving of bodies, it comes to pas that Geometry is commonly referred to their magnitudes, and Mechanics to their motion. In this ene Rational Mechanics will be the cience of motions reulting from any forces whatoever and of the forces required to produce any motions, accurately propoed and demontrated. This part of Mechanics was cultivated by the ancients in the Five Powers which relate to manual arts, who conidered gravity (it not being a manual power) no otherwie than as it moved weights by thoe powers. Our design, not repecting arts, but philoophy, and our ubject, not manual, but natural powers, we conider chiefly thoe things which relate to gravity, levity, elatic force, the reitance of fluids, and the like forces, whether attractive or impulive; and therefore we offer this work as mathematical principles of philoophy. For all the difficulty of philoophy seems to conit in this, from the phenomena of motions to invetigate the forces of nature, and then from thee forces to demontrate the other phenomena. And to this end the general propoitions in the firt and econd book are directed. In the third book we give an example of this in the explication of''