HINTS TO TRAVELLERS SCIENTIFIC AND GENERAL TENTH EDITION _REVISED AND CORRECTED_ FROM THE NINTH EDITION EDITED FOR THE Council of the Royal Geographical Society BY E. A. REEVES, F.R.A.S., F.R.G.S. _Map Curator and Instructor in Surveying to the Royal Geographical Society._ VOL. II. METEOROLOGY, PHOTOGRAPHY, GEOLOGY, NATURAL HISTORY, ANTHROPOLOGY, INDUSTRY AND COMMERCE, ARCHÆOLOGY, MEDICAL, ETC. LONDON THE ROYAL GEOGRAPHICAL SOCIETY KENSINGTON GORE, S.W. 7 _AND AT ALL BOOKSELLERS_ 1921 _Price of the two Volumes, 21s. net. To Fellows, at the Office of the Society, 15s. net._ LONDON: PRINTED BY WILLIAM CLOWES AND SONS, LIMITED, DUKE STREET, STAMFORD STREET, S.E. 1, AND GREAT WINDMILL STREET, W. 1. PREFACE TO VOL. II. The first seven sections of this volume have been carefully revised, but required no serious alteration. The eighth section required very extensive changes and additions, due to the great progress of Tropical Medicine in the last fourteen years. The Society is much indebted to Dr. Andrew Balfour, C.B., C.M.G., Director-in-Chief of the Wellcome Bureau of Scientific Research, who has very kindly revised and extended the Medical Hints in the light of his wide experience in the Sudan and in the East during the War. In the instructions for the use of drugs the word “tablet” has been used to denote products compressed in the form usually described by a proprietary word that belongs in law only to the products of a particular firm. A. R. H. CONTENTS. PAGE SECTION I. METEOROLOGY AND CLIMATOLOGY (by Hugh Robert Mill, D.SC., LL.D., F.R.S.E., formerly President Royal Meteorological Society and Director British Rainfall Organization) 1-50 General Remarks, 1—A Record of Weather, 2—Non-Instrumental Observations, 3—Instrumental Observations, 11—Observations for Forecasting the Weather, 32—Extra-European Weather Services, 42—Table of Relative Humidity, 44—Table showing Pressure of Saturated Aqueous Vapour in Inches of Mercury at Lat. 45° for each degree Fahr. from -30° to 119°, 50—Isothermal, Isobaric, and Rainfall Maps, 50. SECTION II.