tions are ſwift or ſlow, or none at all: and therefore it ought to be diſtinguiſh'd from what are only ſenſible meaſures thereof; and out of which we collect it, by means of the Aſtronomical equation. The neceſſity of which Equation, for determining the Times of a phænomenon, is evinc'd as well from the experiments of the pendulum clock, as by eclipſes of the Satellites of Jupiter.
As the order of the parts of Time is immutable, ſo alſo is the order of the parts of Space. Suppoſe thoſe parts to be mov'd out of their places, and they will be moved (if the expreſſion may be allowed) out of themſelves. For times and ſpaces are, as it were, the Places as well of themſelves as of all other things. All things are placed in Time as to order of Succeſſion; and in Space as to order of Situation. It is from their eſſence or nature that they are Places; and that the primary places of things ſhould be moveable, is abſurd. Theſe are therefore the abſolute places; and tranſlations out of thoſe places, are the only Abſolute Motions.
But becauſe the parts of Space cannot be ſeen, or diſtinguiſhed from one another by our Senſes, therefore in their ſtead we uſe ſenſible meaſures of them. For from the poſitions and diſtances of things from any body conſider'd as immovable, we define all places: and then with reſpect to ſuch places, we eſtimate all motions, conſidering bodies as tranſfer'd from ſome of thoſe places into others. And ſo inſtead of abſolute places and motions, we uſe relative ones; and that without any inconvenience in common affairs: but in Philoſophical diſquiſitions, we ought to abſtract from our ſenſes, and conſider things themſelves, diſtinct from what are only ſenſible meaſures of them. For it may
be that there is no body really at reſt, to which the places and motions of others may be referr'd.
