ADVERTISEMENT. THESE Philofophical Dialogues have been univerfally well received, and found to answer the purpose which their learned and pious author had in view; the advancement and defence of true religion; in oppofition to the Sceptical refinements of fome late writers: and this, by fixing its principles and obligations on an invariable and fure foundation, the divine attributes, as clearly displayed in the works of nature. A miftake, however, in the aftronomical theory, which the author did not live to rectify (as he intended) bad difgufted fome readers; and might have created a prejudice against those parts of the work which, for the execution * Mr. William Baxter, author of the Enquiry into the Human Soul. Stahould be Andrew. as as well as the defign, were altogether unexceptionable. To remove this ftumbling block, the conference, which was chiefly affected by that mistake, is entirely fuppressed, and another added to fill up the vacancy. In this, the occafion of the error is pointed out, and obviated; the doctrine of centripetal forces is carried farther;-and their quantities and effects exemplified in fome of the more remarkable inftances:-the whole in as near a conformity to the author's plan as could be contrived; and requiring little more than a competent knowledge of common arithmetic. The prefent fate of aftronomy fuggeted another addition till. The notion of the mundane fyftem, which youth get from their tutors, is ofteneft imperfect and fuperficial; while the physical aftronomy, cultivated by the great masters, is too fublime for common ufe; and, with every new improvement, grows more and more intricate and forbidding. But But an aftronomy more generally useful, and of eafy application, is, what we may call, the popular, or arithmetical; accommodated to the fervice of the bufbandman, the Seaman, and the clergyman; and particularly of the hiftorian and chronologer. This was probably the primitive aftronomy of Babylon, Egypt, and China, though now neglected and almost forgot; nor indeed have the grounds of it ever been properly explained. And yet fome late publications have fhewn the neceffity of restoring it, in its ancient genuine form of temporary cycles and periods: and thefe not founded in fanciful criticism, but deduced from actual obfervations, in a legitimate demonftrative way. Be this faid without offence to the Mofaic aftronomers, whofe candor and ingenuity are not impeached or fufpected. What might mislead them, was the confiftency of a cycle with itself, which they feem to take for a proof of of its being the true cycle. In this they were greatly deceived; for fuch confiftency proves only the truth of arithmetical rules, but can fignify nothing towards determining the quantities of the revolutions on which the cycle is to be conftructed: these must be had from obfervation only. Another, but less excufable, error of those gentlemen, is their obftinacy in maintaining the commenfurability and perfect equability of the heavenly motions; this, we fay, can hardly admit of an excufe; because it contradicts univerfal experience, and the teftimony of their own fenfes, if they would take the trouble to use them. THE THE CONTENTS. The Firft CONFERENCE. Matho, a boy of a fine genius, defires his friend Philon to explain, and, if poffible, bring with- in the reach of a boy's capacity fome things in philofophy, concerning the heavens and the earth; fuch, to wit, as were most necessary to be known, and likewife pleafant: that thofe of his age might the fooner accustom themselves to the contemplation of truth, and the study of nature, instead of paffing the firft ftage of their lives in the fludy of words only: whereupon they enter on the confi The Spherical figure of the earth demonftrated from other arguments: of the usefulness and neceffity of mountains of the magnitude of the earth and moon: of the distances of the moon and fun from the earth. The absurdity of supposing the heavens and whole frame of nature to whirl round in four and twenty hours: that inftead of this monstrous converfion, the earth only performs a revolution on its own axis in the fame time. The order and periodical revolutions of the planets in the folar |