Page:Philosophical Transactions - Volume 004.djvu/201

 Motion, or the want of strength, by the length of time.

2. Of the Descent of Heavy Bodies, and the Declivity of Motion, Thirty four Propositions. In which he doth not think fit to explicate the Physical Cause of Gravity, whether it proceed from an innate quality in the Heavy Body it self; or an Universal Tendency of Circum-ambient Bodies to the Center, or at Magnetical Power in the Earth, or the like; but contents himself (his purpose requiring no more) to understand by the word Gravity, that sensible force of moving downwards, or to a certain Point, both the Heavy, Body it self, and the less powerful Impediments: Shewing in this Part also, in what proportion the different Declivities of Oblique or Sloping Plains, in which a Heavy Body is supposed to be moved, doth operate to the Helping or Hindering of such Motion. All which he delivers as generally applicable to-Motions, produced by any other force, as well as that of Gravity; and directed any other way as well as downward.

3. The Doctrine of the Libra, or Ballance (containing the Fundamental Principles of all Staticks) in Twenty five Propositions; among which, he explains the Geometrical Considerations requisite in making both exact Common Scales, and the Roman Statera.

On this of the Libra, depends (that which is the subject of the next Part, almost finisht at the Press) the whole Doctrine of the Center of Gravity, and