I judge it will be quite unnecessary to say any thing about the Order of the Work, since that would be only a Repetition of the Table of Contents, to which the Reader is referred, as to the properest Account that can here be given. [Illustration] THE CONTENTS. LETTER THE FIRST. _Concerning the Opinions of the most eminent Authors whose Sentiments upon this Subject have been published in their Works._ Page 1 LETTER THE SECOND. _Concerning the Nature of Mathematical Certainty, and the various Degrees of Moral Probability proper for Conjecture._ 9 LETTER THE THIRD. _Concerning the Nature, Magnitude, and Motion of the Planetary Bodies round the Sun._ 18 LETTER THE FOURTH. _Of the Nature of the heavenly Bodies continued, with the Opinions of the Antients concerning the Sun and Stars._ 27 LETTER THE FIFTH. _Of the Order, Distance, and Multiplicity of the Stars, the_ Via Lactea, _and Extent of the visible Creation._ 37 LETTER THE SIXTH. _Of General Motion amongst the Stars, the Plurality of Systems, and Innumerability of Worlds._ 48 LETTER THE SEVENTH. _The Hypothesis, or Theory, fully explained and demonstrated, proving the sidereal Creation to be finite._ 58 LETTER THE EIGHTH. _Of Time and Space, with regard to the known Objects of Immensity and Duration._ 67 LETTER THE NINTH. _Reflections, by way of_ General Scolia, _of Consequences relating to the Immortality of the Soul, and concerning Infinity and Eternity._ 77 Directions for placing the PLATES.