Difference between aphelion & perihelion distance 14, 212,700 miles. N. WINTER SOLSTICE IN PERIHELION. FRONTISPIECE CLIMATE AND TIME bat IN THEIR GEOLOGICAL RELATIONS: A THEORY OF SECULAR CHANGES OF THE EARTH'S CLIMATE. BY JAMES CROLL, OF HER MAJESTY'S GEOLOGICAL SURVEY OF SCOTLAND. STANFORD NEW YORK: D. APPLETON AND COMPANY, 1, 3, AND 5 BOND STREET. 1893. st PREFACE TO THE FIRST EDITION. In the following pages I have endeavoured to give a full and concise statement of the facts and arguments adduced in support of the theory of Secular Changes of the Earth's Climate. Considerable portions of the volume have already appeared in substance as separate papers in the Philosophical Magazine and other journals during the past ten or twelve years. The theory, especially in as far as it relates to the cause of the glacial epoch, appears to be gradually gaining acceptance with geologists. This, doubtless, is owing to the greatly increased and constantly increasing knowledge of the drift-phenomena, which has induced the almost general conviction that a climate such as that of the glacial epoch could only have resulted from cosmical causes. Considerable attention has been devoted to objections, and to the removal of slight misapprehensions, which have naturally arisen in regard to a subject comparatively new and, in many respects, complex, and beset with formidable difficulties. I have studiously avoided introducing anything of a hypothetical character. All the conclusions are based either on known facts or admitted physical principles. In short, the aim of the work, as will be shown in the introductory chapter, is to |