TO THE READER.

This Book was juſt finiſhed, and deſigned for the Preſs, when the Author, to the great loſs of the Learned World, was ſeized by a Diſeaſe that brought him to his Death. However he took care in his laſt Will of its Publication, deſiring his Brother, to whom it was writ, to take that Trouble upon him. But he was ſo taken up with Buſineſs and Removals, (as being Secretary in Holland to the King of Great Britain) that he could find no time for it till a Year after the Death of the Author: When it ſo fell out, that the Printers being ſomewhat tardy, and this Gentleman dying, the Book was left without either Father or Guardian. Yet it now ventures into the Publick, in the ſame Method that it was writ by the Author, and with the ſame Inſcription to his Brother, tho’ dead; in confidence that this laſt Piece of his will meet with as kind a Reception from the World as all the other Works of that Author have. ’Tis true there are not every where Mathematical Demonſtrations; but where they are wanting, you have probable and ingenious Conjectures, which is the moſt that can be reaſonably expected in ſuch matters. What belongs to, or has any thing to do with Aſtronomy, you will ſee demonſtrated, and the reſt ingeniouſly and ſhrewdly gueſs’d at, from the Affinity and Relation of the heavenly Bodies to the Earth. For your farther Satisfaction read on, and farewel.