200.69 DAYS. Perikalian distance 64, 23, 50 miles. Aphelion distance 98.506.350 miles. (Glau N.P. 164.55 DAYS. Difference between aphelion & perihelion distance 14, 212,700 miles. N. WINTER SOLSTICE 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. NEW YORK: D. APPLETON AND COMPANY, 1, 3, AND 5 BOND STREET. 1890. Geol. QE 698 .092 18000 PREFACE TO THE FIRST EDITION. In the following pages I have endeavoured to give a full aud Considerable attention has been devoted to objections, and to 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 17684 The University of Lon prove that secular changes of climate follow, as a necessary effect, from admitted physical agencies, and that these changes, in as far as the past climatic condition of the globe is con cerned, fully meet the demand of the geologist. The volume, though not intended as a popular treatise, will be found, I trust, to be perfectly plain and intelligible even to readers not familiar with physical science. I avail myself of this opportunity of expressing my obligations to my colleagues, Mr. James Geikie, Mr. Robert L. Jack, Mr. Robert Etheridge, jun., and also to Mr. James Paton, of the Edinburgh Museum of Science and Art, for their valuable assistance rendered while these pages were passing through the press. To the kindness of Mr. James Bennie I am indebted for the copious index at the end of the volume, as well as for many of the facts relating to the glacial deposits of the West of Scotland. EDINBURGH, March, 1875. |