, and of dust.

[Illustration: PLATE I. ANNUAL DISTRIBUTION OF TEMPERATURE AND
PRESSURE.]

[Illustration: PLATE I. SEASONAL DISTRIBUTION OF TEMPERATURE AND
PRESSURE.

TEMPERATURE JANUARY
TEMPERATURE JULY
PRESSURE & WINDS JANUARY
PRESSURE & WINDS JULY]

_Coast or Littoral Climate._--Between the pure marine and the pure
continental types the coasts furnish almost every grade of transition.
Prevailing winds are here important controls. When these blow from the
ocean, the climates are marine in character, but when they are
off-shore, a somewhat modified type of continental climate prevails,
even up to the immediate sea-coast. Hence the former have a smaller
range of temperature; their summers are more moderate and their winters
milder; extreme temperatures are rare; the air is damp, and there is
much cloud. All these marine features diminish with increasing distance
from the ocean, especially when there are mountain ranges near the
coast. In the tropics, windward coasts are usually well supplied with
rainfall, and the temperatures are modified by sea breezes. Leeward
coasts in the trade-wind belts offer special conditions. Here the
deserts often reach the sea, as on the western coasts of South America,
Africa and Australia. Cold ocean currents, with prevailing winds
along-shore rather than on-shore, are here hostile to rainfall, although
the lower air is often damp, and fog and cloud are not uncommon.

_Monsoon Climate._--Exceptions to the general rule of rainier eastern
coasts in trade-wind latitudes are found in the monsoon regions, as in
India, for example, where the western coast of the peninsula is
abundantly watered by the wet south-west monsoon. As monsoons often
sweep over large districts, not only coast but interior, a separate
group of monsoon climates is desirable. In India there are really three
seasons--one cold, during the winter monsoon; one hot, in the transition
season; and one wet, during the summer monsoon. Little precipitation
occurs in winter, and that chiefly in the northern provinces. In low
latitudes, monsoon and non-monsoon climates differ but little, for
summer monsoons and regular trade-winds may both give rains, and wind
direction has slight effect upon temperature.

The winter monsoon is off-shore and the summer monsoon on-shore under
typical conditions, as in India. But exceptional cases are found where
the opposite is true. In higher latitudes the seasonal changes of the