The author acknowledges courtesies extended to him by Prof. Charles F. Marvin, present chief of the Weather Bureau, and by R. H. Weightman, chief clerk of the Bureau, in the matter of securing several important illustrations; and like favors extended to him by D. Appleton and Company, John Wiley & Sons, and the Taylor Instrument Company, of Rochester, N. Y. W. L. M. AUGUST, 1922 CONTENTS CHAPTER PAGE INTRODUCTION vii I ATMOSPHERES OF THE EARTH, THE SUN, AND THE PLANETS 1 II A SYNOPTIC PICTURE OF THE AIR 7 III EXPLORATIONS OF THE ATMOSPHERE 18 IV EARTH’S FOUR ATMOSPHERES 29 V LIGHT, HEAT, AND TEMPERATURE 48 VI THE ADVANTAGE OF TAKING WEATHER OBSERVATIONS AND APPLYING THEM TO ONE’S PERSONAL NEEDS 64 VII FROST 85 VIII WIND AND PRESSURE OF THE GLOBE 98 IX HOW TO FORECAST FROM THE DAILY WEATHER MAP 112 X CLIMATE 161 XI HOW CLIMATE IS MODIFIED AND CONTROLLED 188 XII CIVILIZATION FOLLOWS THE STORM TRACKS 213 XIII HAS OUR CLIMATE CHANGED? 225 XIV CLIMATES FOR HEALTH AND PLEASURE 245 XV CONDENSATION 282 XVI DEVELOPMENT OF THE AMERICAN WEATHER SERVICE 291 INDEX 307 LIST OF FIGURES Instrument Shelter (Figure 4) _Frontispiece_ FIGURE PAGE 1. Winter and Summer Vertical Temperature Gradients, in degrees Centigrade and Fahrenheit 12 2. Showing light from lamp a passing into dust-free air at _b_, and passing out at _c_ without illuminating the interior 46 3. Standard Weather Bureau Kite 64 5. Comparison of the Thermometer Scales 67 6. Dry and Wet Bulb Thermometers 68 7. Mercurial Barometer 78 8. Continuous records of the temperature from 4 P.M. to 9 A.M. 87 9. Continuous records of the temperature 5 feet and 35 feet above ground on a tower in a pear orchard 95 10. Average dates of last killing frost in Spring 96 11. Average dates of first killing frost in Fall 97 12. Trade wind circulation 99