0 ELEMENTS OF GEOMETRY; 1 CONTAINING THE FIRST SIX BOOKS OF EUCLID, WITH A SUPPLEMENT ON THE QUADRATURE OF THE CIRCLE AND THE GEOMETRY OF SOLIDS; TO WHICH ARE ADDED, ELEMENTS OF PLANE AND SPHERICAL TRIGONOMETRY. SECOND EDITION, ENLARGED, BY JOHN PLAYFAIR, F. R. S. EDIN. OF EDINBURGH, CEDINBURGH: PRINTED FOR BELL & BRADFUTE; AND G. & J. ROBINSON, LONDON. Edine T20 148.04,700 1857. april. 25. hers N. A. Gifts Gift of of Portsmouth N. Ib. ENTERED IN STATIONERS HALL. Edinburgh, } 30-329 48 PREFACE. Tis a remarkable fact in the history of science, that the oldest book of Elementary Geometry is still confidered as the best, and that the writings of EUCLID, at the distance of two thousand years, continue to form the most approved introduction to the mathematical sciences. This remarkable distinction the Greek geometer owes 'not only to the elegance and correctness of his demonstrations, but to an arrangement most happily contrived for the purposes of inftruction; advantages which, when they reach a certain eminence, secure the works of an author against the injuries of time, more effectually than even originality of invention. The Elements of EUCLID, however, in paffing through the hands of the ancient editors, during the decline of science, had fuffered fome diminution of their excellence, and much skill and learning have been employed by the modern mathematicians to deliver them from blemishes, which certainly did not enter into their original compofition. a2 |