Transcriber Note Since § 134 appeared on page 143 and again on page 147, the Section number on pages 147 and all succeeding were incremented. The Table of Contents was also incremented respectively. Text emphasis denoted by _Italics_. List of ERRATA below has been applied to the text. ERRATA. Page 44. line 4. from the bottom, _for_ that _read_ as " 189. " 6. " _for_ appearenes _read_ appearances " 464. " 4. " _for_ D'AUBENTON _read_ DAUBENTON " 482. " 12. " _for_ adversaries _read_ adversary ILLUSTRATIONS OF THE HUTTONIAN THEORY OF THE EARTH BY JOHN PLAYFAIR F. R. S. EDIN. AND PROFESSOR OF MATHEMATICS IN THE UNIVERSITY OF EDINBURGH. ========================================================= Nunc naturalem causam quærimus et assiduam, non raram et foriuitam. SENECA. ========================================================= EDINBURGH: PRINTED FOR CADELL AND DAVIES, LONDON, AND WILLIAM CREECH, EDINBURGH. ====== 1802. Entered in Stationers Hall. NEILL & CO. } Printers, Edinburgh } ADVERTISEMENT. THE Treatise here offered to the Public, was drawn up with a view of explaining Dr Hutton's Theory of the Earth in a manner more popular and perspicuous than is done in his own writings. The obscurity of these has been often complained of; and thence, no doubt, it has arisen, that so little attention has been paid to the ingenious and original speculations which they contain. THE simplest way of accomplishing the object proposed, seemed to be, to present a General Outline of the System, in one continued Discourse; and to introduce afterwards, in the form of Notes, what farther elucidation any particular subject was thought to demand. Through the whole, I have aimed at little more than a clear exposition of facts, and a plain deduction of the conclusions grounded on them; nor shall I claim any merit to myself, if, in the order which I have found it necessary to adopt, some arguments may have taken a new form, and some additions may have been made to a system naturally rich in the number and variety of its illustrations.