Quarterly Review on "Scrope's Geology of Central France." These papers all indicate powers of observation and comparison of a high order, and prepared the geological world for the appearance of the work on which, above all others, the reputation of Sir Charles Lyell mainly rests; this was his Principles of Geology. The first volume of this work appeared in January, 1830, the second in January, 1832, and the third volume in May, 1833. Such, bowever, was the impression produced by this work, that second editions of the first and second volumes were required before the third volume appeared. A third edition of the whole work, in four volumes, appeared in May, 1834, a fourth edition in 1835, and a fifth in 1837. This work treated geology from two points of view. First, the history of the earth was examined with regard to its modern changes, and the causes producing them; second, an account was given of those monuments of analogous changes of ancient date: the first comprehending an account of the forces at work producing geological changes, and the second presenting a survey of the changes that had been accomplished in the past. As new editions of these works were required, and materials accumulated, the author was induced to separate the two parts of the work, and in 1838 he published a volume, entitled Elements of Geology, which contained a more full and elaborate treatment of that part of the first work devoted to the ancient history of the earth, or what may be called geology proper. A second edition of this work, in two volumes, appeared in 1841. This work was again produced in one large volume in 1851, with the title of Manual of Elementary Geology. A fourth edition appeared in 1852, and a fifth has since appeared. The Principles were again published in three volumes in 1840, and in one large volume in 1847, 1850, and 1853.

Of these works, Sir Charles says, in his preface to the ninth edition of the Principles: "The Principles treat of such portions of the economy of existing nature, animate and inanimate, as are illustrative of geology, so as to comprise an investigation of the permanent effects of causes now in action, which may serve as records to after ages of the present

condition of the globe and its inhabitants. Such effects are the enduring monuments of the ever-varying state of the physical geography of the globe the lasting signs of its destruction and renovation, and the memorials of the equally fluctuating condition of the organic world. They may be regarded as a symbolical language, in which the earth's autobiography is written. In the Manual of Elementary Geology, on the other hand, I have treated briefly of the component materials of the earth's crust, their arrangement and relative position, and their organic contents, which, when deciphered by aid of the key supplied by the study of the modern changes above alluded to, reveal to us the annals of a grand succession of past events-a series of revolutions which the solid exterior of the globe and its living inhabitants have experienced in times antecedent to the creation of man." Such is the author's account of the two great works, which more than any others have exercised an influence on the progress and development of geological science. It was undoubtedly the Principles that called the attention of geologists to the necessity of regarding the past changes of the earth's surface as resulting from causes now in operation. It demanded that geological science should be placed upon the same foundation as the other inductive sciences, and that those causes which could not be demonstrated to have existed should cease to influence the theories of the geologist. This work was at once acknowledged by the abler geologists of the day as an expression of the principles of their science. It met, however, with great opposition from those who imagined that it interfered with the authoritative declarations of Scripture. Sir Charles Lyell's own university was most decided in its opposition to the new views, although its able professor of geology was not so. At the present time, the position taken by the author of the Principles is generally acknowledged as the only one consistent with a philosophical pursuit of geological scienc, and the theologian has admitted the necessity of adapting his opinions to the requirements of correct reasoning and undoubted facts. But whilst Sir Charles has thus the merit of having placed geology on a true and scientific basis, he is