the two coasts. These two sets of conditions are often very close together, with a divide between them. On the island of Hawaii, Hilo, on the east side, is exposed to the north-east trade and has a winter maximum of rainfall. Kailua, on the lee side, has about one-third as much rainfall, with a summer maximum. The islands of the East Indian archipelago furnish many examples of such curious complications. The eastern coast of Madagascar has south-east trade winds fairly uniformly through the year, while the interior and west coast have a summer maximumthe normal tropical rainfall season.

IV. Mountain Climate. Within the tropics, altitude is chiefly important because of its effect in tempering the heat of the lowlands, especially at night. If tropical mountains are high enough, they carry snow the year around, even on the equator, and the zones of vegetation may range from the densest tropical forest at their base to the snow on their summits. The highlands and mountains within the tropics are thus often sharply contrasted with the lowlands, and offer more agreeable and more healthful conditions for white settlement. They are therefore often sought out by residents from colder latitudes as the most attractive resorts. In India, the hill stations are crowded during the hot months by civilian and military officials, and it has been well said that India is ruled from 7,000 feet above sea-level. The climate of many tropical plateaus and mountains has the reputation of being a "perpetual spring."

Thus, on the interior plateau of the tropical Cordilleras of South America, and on the central plateau of tropical Africa, the heat is tempered by the altitude, while the lowlands and coasts are very hot. The rainfall on tropical mountains and highlands often differs considerably in amount from that on the lowlands, and other features common to mountain climates the world over are also noted. But the main emphasis is rightly laid upon the temperature.

CHAPTER V

THE CHARACTERISTICS OF THE ZONES: II.—THE TEMPERATE ZONES

General: "Temperate " Zones-Temperature-Pressure and Winds -Rainfall-Humidity and Cloudiness-Seasons: Their Effects on Man-Weather-Climatic Subdivisions-South Temperate Zone Sub-tropical Belts: Mediterranean Climates-North Temperate Zone: Western Coasts-Interiors-Eastern Coasts -Mountain Climates.

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General: "Temperate" Zones. The so-called temperate" zones occupy about one-half of the earth's surface. As a whole, they are temperate only in that their mean temperatures and their physiological effects are intermediate between those of the tropics and those of the polar zones. The modifications of solar climate which result from the distribution and influence of land and water are greatest in the temperate zones. The north temperate zone includes the greatest known extremes of temperature. If the use of the word "temperate were not so firmly established it would be well to change the name to intermediate, or to middle.1

1 North-middle and south-middle would then distinguish the zones in the two hemispheres. (See W. M. Davis: The Temperate Zones, Journ. Geogr., vol. i, 1897, pp. 139-143.) "Temperate " does, however, apply fairly well to the south temperate zone.

A marked changeableness of the weather is a striking characteristic of these zones. Apparently irregular and haphazard, these continual weather changes nevertheless run through a fairly systematic series, although they are essentially non-periodic. Climate and weather are by no means synonymous over most of the extra-tropical latitudes.

Temperature. The mean annual temperatures at the margins of the north temperate zone differ by more than 70°. The ranges between the mean temperatures of hottest and coldest months reach 120° at their maximum in north-eastern Siberia, and 80° in North America. A January mean of -60° and a July mean of 95°, and maxima of over 120° and minima of -90°, occur in the same zone. In the districts of lowest winter minima, the mean summer temperatures exceed 85°, and in portions of the districts of highest mean summer maxima, the mean winter minima fall below 32°. Such great ranges characterise the extreme land climates. Under the mild influence of the oceans, the windward west coasts have much smaller ranges than the interiors; the seasonal differences increase inland. The annual ranges in the middle and higher latitudes exceed the diurnal, the conditions in much of the torrid zone being exactly reversed. Over much of the oceans of the temperate zones the annual range is less than 10°. In the south temperate zone there are no extreme ranges, the maxima, slightly over 30°, being near the margin of the zone in the interior of South America, south

Africa, and Australia. In these same localities, the diurnal ranges, however, rival those of the north temperate zone.

The north-eastern Atlantic ocean and north-western Europe are about 35° too warm for their latitude in January, while north-eastern Siberia is 30° too cold. The lands north of Hudson's Bay are 25° too cold, and the waters of the Alaskan Bay 20° too warm. In July, and in the southern hemisphere, the anomalies are small. The lands which are the centre of civilisation in Europe average too warm for their latitudes. These lands are the most truly "temperate " portion of the north temperate zone. The northwest coast of North America is much the same. The diurnal variability of temperature is greater in the north temperate zone than elsewhere in the world, and the same month may differ greatly in its character in different years. One winter in higher latitudes may have much snow, and temperatures below normal; the next may give much rain instead of snow, and the ground remain unfrozen. One summer may be very favourable for crops; the next may give a poor harvest.

From the point of view of temperature, these zones may be considered in three divisions: (1) the subtropical, (2) the "temperate " latitudes, and (3) the sub-polar. The annual temperature curve has one maximum and one minimum. In the continental type, the times of maximum and minimum are about one month behind the maximum and minimum in