ployment which requires the Authour's persevering attention for more than eight hours in the day, and leaves him scarcely leisure sufficient to remove, by exercise, the injury done to health by such close confinement. Nothing but an earnest desire to promote the cause of science could have tempted him to relinquish the advantages of exercise, and appropriate his leisure to the composition of this treatise; and if, through the want of either time or ability, he has failed of accomplishing the purpose he had in view, he trusts it will be forgiven, when he assures the public he should never have attempted to supply the want of a work of this kind, had it appeared probabie that any other person would undertake it speedily. The Authour cannot conclude this Preface before he has acknowledged his obligations to preceding writers on Astronomy, from whose labours he has, in many respects, derived considerable benefit: indeed, he is free to confess, that his treatise has few claims to originality, except in point of arrangement; and, if the plan he has pursued be, on the whole, productive of advantage to the student or the science, his grand object will be attained. Nevertheless, as he is solicitous to improve his work as far as possible, he earnestly intreats that those who discover any errours therein, either in method, in principle, or in computation, will have the goodness to make them known to the Authour, that they may be corrected in a future edition, should the performance be so far approved as to render another edition necessary. Cambridge, May 20, 1801. Now publishing in Parts, monthly, by G.KEARSLEY, Fleet-street, to be comprised in four large Volumes Sco. with numerous Plates: THE MATHEMATICAL AND PHYSICAL RECREATIONS OF M. OZANAM; THE LAST EDITION, By M. de MONTUCLA : Translated, with numerous Additions and Corrections, By CHARLES HUTTON, LL.D. F.R.S. PROFESSOR OF MATHEMATICS IN THE ROYAL ACADEMY, WOOLWICH. Likewise just published, in one large Volume 12mo. Price 5s. 6d. in Boards: SELECT AMUSEMENTS IN PHILOSOPHY AND MATHEMATICS, PROPER FOR AGREEABLY EXERCISING THE MINDS OF YOUTH: Translated from the French of WITH SEVERAL CORRECTIONS AND ADDITIONS, PARTICULARLY A LARGE TABLE OF THE CHANCES OR ODDS AT PLAY: THE WHOLE RECOMMENDED AS AN USEFUL BOOK FOR SCHOOLS, By Dr. HUTTON. II. Explanation of Terms relating to some imaginary Points, Lines, and Circles, on the Earth, and in the Heavens. 12 III. On the apparent Motion of the heavenly Bodies, particularly of the Sun; the IV. On determining the relative Situation of the fixed Stars; with Remarks on VI. On the Rising, Setting, &c. of the Sun VII. On the celebrated Systems of Astronomy 127 VIII. On the Truth of the Copernican System 145 IX. On the Theory of apparent Motions 151 . 345 XXII. On the Aberration of Light XXIII. On the Latitude and Longitude XXIV. On the Distances, &c. of the fixed I. Of the Sun's Longitude 388 417 A TREATISE ON ASTRONOMY. CHAPTER I. On the Figure and Dimensions of the Earth ART. 1. To determine the distances, magnitudes, and orbits, of the heavenly bodies; to describe their various apparent motions, and explain them by shewing their dependence upon the real motions from which the appearances result; to exhibit the laws by which these bodies are regulated; and to trace the re lations and dependences of these laws so far as we are enabled to develope them, is the business of that branch of natural philosophy which is called ASTRONOMY: a science which, from the certainty and evidence of its demonstrations, from the great and manifest advantages with which it furnishes us, and from the vast amplitude and sublimity of that universe which it proposes for our contemplation, is admirably calculated B |