I Doubt not but I ſhall incur the Cenſures of learned Men for putting this Book into Engliſh, becauſe, they’ll ſay, it renders Philoſophy cheap and vulgar, and, which is worſe, furniſhes a ſort of injudicious People with a ſmattering of Notions, which being not able to make a proper uſe of, they pervert to the Injury of Religion and Science. I confeſs the Allegation is too true: but after Biſhop Wilkins, Dr. Burnet, Mr. Whiſton and others, to ſay nothing of the ancient Philoſophers, who wrote in their own Tongues; I ſay, after theſe great Authors have treated on as learned and abſtruſe Subjects in the ſame Language, I hope their Example will be allowed a ſufficient excuſe for printing this Book in Engliſh. Concerning this Edition I can ſay, that I have taken care to have the Cutts exactly done, and have placed each Figure at the Page of the Book that refers to it, which I take to be more convenient to the Reader than putting them all at the End. I have been careful to procure the beſt Paper, that I might in ſome meaſure come up to the Beauty of the Latin Edition, though this bear but half the Price of it. And I hope the Tranſlator has expreſſed the Author’s Senſe aright, and has not committed Faults beyond what an ingenuous Reader can pardon. NEW CONJECTURES Concerning the Planetary Worlds, THEIR INHABITANTS AND PRODUCTIONS. Written by Christianus Huygens, and inſcribed to his Brother Constantine Huygens. BOOK the Firſt.