CHANGES OF CLIMATE 338 Popular belief in climatic change—Evidence of climatic changes within historic times—What meteorological records show—Why the popular belief in climatic changes is untrustworthy—Value of evidence concerning changes of climate—Periodic oscillations of climate: the sunspot period—Brückner’s 35-year cycle—Climatic cycles of longer period—Geological changes in climate—Conclusion.

INDEX 373

ILLUSTRATIONS.

FIG. PAGE

1 DISTRIBUTION OF INSOLATION OVER THE EARTH 8 2 ANNUAL VARIATION OF INSOLATION AT DIFFERENT LATITUDES 10 3 INSOLATION RECEIVED AT DIFFERENT LATITUDES ON JUNE 21 14 4 THE ZONES IN THE TIME OF PARMENIDES 22 5 SUPAN’S TEMPERATURE ZONES 25 6 TEMPERATURE ZONES AFTER KÖPPEN 27 7 INFLUENCE OF LAND AND WATER ON THE ANNUAL MARCH OF AIR TEMPERATURE 39 8 DIURNAL VARIATION OF PRESSURE: INFLUENCE OF ALTITUDE 48 9 DIURNAL VARIATION OF TEMPERATURE: INFLUENCE OF ALTITUDE 50 10 SUPAN’S CLIMATIC PROVINCES 56 11 GENERAL DISTRIBUTION OF PLANT ZONES 63 12 SCHEME OF CLIMATES AT SEA-LEVEL 64 13 NAMES OF CLIMATES AT SEA-LEVEL 65 14 VERTICAL DISTRIBUTION OF CLIMATES 66 15 PRESSURE AND WINDS IN JANUARY 67 16 PRESSURE AND WINDS IN JULY 68 17 KÖPPEN’S CLASSIFICATION OF CLIMATES IN RELATION TO VEGETATION 69 18 HERBERTSON’S MAJOR NATURAL REGIONS 71 19 ANNUAL MARCH OF TEMPERATURE: EQUATORIAL TYPE 91 20 ANNUAL MARCH OF RAINFALL IN THE TROPICS 92 21 ANNUAL MARCH OF CLOUDINESS IN THE TROPICS 95 22 ANNUAL MARCH OF TEMPERATURE: TROPICAL TYPE 97 23 MONTHLY DISTRIBUTION OF RAINFALL: SUB-TROPICAL WINTER RAINS 125 24 RAINY AND RAINLESS ZONES ON EASTERN ATLANTIC COAST 128 25 ANNUAL MARCH OF TEMPERATURE FOR SELECTED SUB-TROPICAL STATIONS 131 26 ANNUAL MARCH OF CLOUDINESS IN A SUB-TROPICAL CLIMATE 133 27 ANNUAL MARCH OF TEMPERATURE FOR SELECTED STATIONS IN THE TEMPERATE ZONES 135 28 ANNUAL MARCH OF RAINFALL: TEMPERATE ZONES 139 29 ANNUAL MARCH OF CLOUDINESS IN CONTINENTAL AND MOUNTAIN CLIMATES: TEMPERATE ZONES 147 30 JANUARY NORTH POLAR ISOTHERMS 155 31 JULY-NORTH POLAR ISOTHERMS 156 32 MEAN ANNUAL NORTH POLAR ISOTHERMS 158 33 ANNUAL MARCH OF TEMPERATURE: POLAR TYPE 164 34 ANNUAL MARCH OF CLOUDINESS IN THE NORTH POLAR ZONE: MARINE TYPE 173

ACKNOWLEDGMENT OF ILLUSTRATIONS.

Fig. 1. W. M. Davis: _Elementary Meteorology_. ” 2, 3, 7, 8, 9. A. Angot: _Traité élémentaire de Météorologie_. ” 4. H. Berger: _Geschichte der wissenschaftlichen Erdkunde der Griechen_. ” 5, 10, 24. A. Supan: _Grundzüge der physischen Erdkunde_. 3d edition. ” 6. W. Köppen: _Die Wärmezonen der Erde, nach der Dauer der heissen, gemässigten und kalten Jahreszeit, und nach der Wirkung der Wärme auf die organische Welt betrachtet. Met. Zeitschr._, i, 1884. ” 11, 12, 13, 14, 15, 16, 17. W. Köppen: _Versuch einer Klassifikation der Klimate, vorzugsweise nach ihren Beziehungen zur Pflanzenwelt_. Hettner’s _Geogr. Zeitschr._, vi, 1900. ” 18. A. J. Herbertson: _The Major Natural Regions. Geogr. Jour._, xxv, 1905. ” 30, 31, 32. _Scientific Results of the Norwegian North Polar Expedition_. Vol. vi, _Meteorology_.

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