ficult to discern without careful observation. Cyclonic storms are
most numerous and best developed in winter. Although greatly interfered
with near sea-level by continental changes of pressure, by cyclonic and
anticyclonic whirls, and by local inequalities of the surface, the
eastward movement of the atmosphere remains very constant aloft. The
south temperate zone being chiefly water, the westerlies are but little
disturbed there by continental effects. Between latitudes 40 deg. and 60
deg. S. the "brave west winds" blow with a constancy and velocity found
in the northern hemisphere only on the oceans, and then in a modified
form. Storms, frequent and severe, characterize these southern
hemisphere westerlies, and easterly wind directions are temporarily
noted during their passage. Voyages to the west around Cape Horn against
head gales, and in cold wet weather, are much dreaded. South of Africa
and Australia, also, the westerlies are remarkably steady and strong.
The winter in these latitudes is stormier than the summer, but the
seasonal difference is less than north of the equator.

_Rainfall._--Rainfall is fairly abundant over the oceans and also over a
considerable part of the lands (30-80 in. and more). It comes chiefly in
connexion with the usual cyclonic storms, or in thunderstorms. So great
are the differences, geographic and periodic, in rainfall produced by
differences in temperature, topography, cyclonic conditions, &c., that
only the most general rules can be laid down. The equatorward margin of
the temperate zone rains is clearly defined on the west coasts, at the
points where the coast deserts are replaced by belts of light or
moderate rainfall. Bold west coasts, on the polar side of lat. 40 deg.,
are very rainy (100 in. and more a year in the most favourable
situations). The hearts of the continents, far from the sea, and
especially when well enclosed by mountains, or when blown over by cool
ocean winds which warm while crossing the land, have light rainfall
(less than 10-20 in.). East coasts are wetter than interiors, but drier
than west coasts. Winter is the season of maximum rainfall over oceans,
islands and west coasts, for the westerlies are then most active,
cyclonic storms are most numerous and best developed, and the cold lands
chill the inflowing damp air. At this season, however, the low
temperatures, high pressures, and tendency to outflowing winds over the
continents are unfavourable to rainfal