In the city of Washington the Government maintains an astronomical and timekeeping institution known as the Naval Observatory, and it maintains in the same city the central office of the United States Weather Bureau. The two establishments are a mile apart in space and nearly a whole library apart in the subjects with which they are concerned. The fact that their functions are persistently confounded by the public indicates the necessity of writing this preface to a popular book on meteorology. CONTENTS CHAPTER PAGE I. THE ANATOMY OF THE ATMOSPHERE 9 II. THE RESOURCES OF THE ATMOSPHERE 24 III. THE ATMOSPHERE AS A HIGHWAY 39 IV. DUST AND SMOKE IN THE ATMOSPHERE 52 V. WEATHER AND WEATHER INSTRUMENTS 66 VI. CLOUDLAND 90 VII. PRECIPITATION 106 VIII. WINDS AND STORMS 123 IX. ATMOSPHERIC ELECTRICITY 141 X. ATMOSPHERIC OPTICS 164 XI. ATMOSPHERIC ACOUSTICS 186 XII. CLIMATE AND CLIMATES 197 XIII. ORGANIZED METEOROLOGY 212 XIV. WEATHER MAPS AND FORECASTS 224 XV. AGRICULTURAL METEOROLOGY 245 XVI. COMMERCIAL METEOROLOGY 261 XVII. MARINE METEOROLOGY 271 XVIII. AERONAUTICAL METEOROLOGY 284 XIX. MILITARY METEOROLOGY 306 XX. MEDICAL AND PHYSIOLOGICAL METEOROLOGY 316 XXI. WEATHER-MAKING 332 XXII. ATMOSPHERIC BYWAYS 346 GLOSSARY 365 LIST OF ILLUSTRATIONS FUNNEL-SHAPED CLOUD OF A TORNADO _Frontispiece_ _Painted from an unusual Photograph_ FACING PAGE EXPLORING THE UPPER AIR--BEGINNING OF A PILOT BALLOON FLIGHT 32 EXPLORING THE UPPER AIR--SENDING UP A SOUNDING BALLOON 32 METEOROGRAPH FOR USE WITH A SOUNDING BALLOON 33 KITE METEOROGRAPH TO BE SENT ALOFT ATTACHED TO A KITE 33 ALTO-CUMULUS--FLEECY MASSES SHOWING BLUE SKY BETWEEN 96 CUMULUS, OR WOOL-PACK CLOUD 96 MAMMATO-CUMULUS, OR “RAIN BALLS” 97 CUMULO-NIMBUS--THE THUNDERCLOUD 97 CLOUD BANNER OVER MOUNT ASSINIBOINE, CANADIAN ROCKIES 100 CIRRUS, WITH LOWER CLOUDS IN THE FOREGROUND 100 LENTICULAR CLOUD OVER MOUNT RAINIER 101 ICE STORM AT PHILADELPHIA--TREES COVERED WITH GLAZE 116