at any time I happen to ſpeak of centres as attracting, or as endued with attractive powers.
Scholium.
Hitherto I have laid down the definitions of ſuch words as are leſs known, and explained the ſenſe in which I would have them to be underſtood in the following discourſe. I do not define Time, Space, Place, and Motion, as being well known to all. Only I must obſerve, that the common people conceive thoſe quantities under no other notions but from the relation they bear to ſenſible objects. And thence ariſe certain prejudices, for the removing of which it will be convenient to diſtinguiſh them into Abſolute and Relative, True and Apparent, Mathematical and Common.
I. Absolute, True, and Mathematical Time, of it ſelf, and from its own nature, flows equably without relation to anything external, and by another name is called Duration: Relative, Apparent, and Common Time, is ſome ſenſible and external (whether accurate or unequable) meaſure of Duration by the means of motion, which is commonly uſed inſtead of True time; such as an Hour, a Day, a Month, a Year.
II Abſolute Space, in its own nature, without relation to anything external, remains always ſimilar and immovable. Relative Space is ſome movable dimenſion or meaſure of the absolute ſpaces; which our ſenſes determine, by its poſition to bodies; and which is vulgarly taken for immovable ſpace; Such is the dimenſion of a ſubterraneous, an aerial, or celeſtial ſpace, determined by its poſition in reſpect of the Earth. Abſolute and Relative ſpace are the ſame in figure and magnitude; but they do not remain always numerically the ſame. For if the Earth, for inſtance, moves;
