prevailing ‘winds throughout the year, at least to the south of 40°8S.,, 
are westerly. 
54. The influence of the pressure of the air over the land in deter- 
mining the direction of the prevailing winds is most marked where 
\here are great bodies of land to the north or south of seas in lower 
latitudes, above all in eastern Asia and in Australia. The interior of 
sastern Asia in summer is a region of very low pressure, in winter of 
very high pressure. Hence, in summer ocean winds, south-westerly, 
southerly, south-easterly, blow over all the south-east of Asia, in- 
cluding the islands, from the Indian peninsula to about the parallel 
of 60° N. During the winter land-winds, north-easterly, northerly, 
north-westerly, prevail in the same region. These are the monsoons, 
which have an important effect on temperature as well as on rainfall. 
The summer winds, though blowing from lower latitudes, do not tend 
bo raise the temperature, because they come from the ocean ; but the 
winter winds being land-winds as well as coming from higher latitudes 
have a marked effect in lowering the temperatures, more particularly 
in the temperate zone. For this reason also the winter temperatures 
in the east of Asia are much lower than those in corresponding lati- 
tudes in the west of Europe and Africa, a fact of great importance in 
commercial geography. In Australia similar results are due to the 
alternation of high and low pressures in the interior, but owing to the 
Jifference of hemisphere the seasons and the directions of the winds 
are reversed. 
55. In consequence of the facts stated with regard to the prevalent 
winds, there is, in the temperate zones, and more particularly in 
the northern hemisphere, a general lowering of the mean temperature 
of the year from west to east, due chiefly to an easterly increase in 
the cold of winter, and partly compensated by an easterly increase 
in the heat of summer. The increase in the extremes of heat and 
cold is greatest in the eastern or broader of the two great land- 
masses, and the coldest region of the earth (so far as explored) lies 
towards the east of Asia, some distance inland, since the sea everywhere 
has some effect in mitigating extremes of temperature. While the 
eastern land-mass thus exhibits greater cold and greater contrasts of 
summer and winter temperature in the east of Asia than are presented 
in the east of America, its western or European portion, being exposed 
to warmer winds traversing a warmer ocean than those which visib 
the western coasts of North America in high latitudes, is characterised 
by a more equable climate and higher winter temperatures than 
corresponding latitudes on the latter coasts ; and, in general, we find 
that when we compare equal latitudes in the west of America and 
the west of Europe, the latter continent shows the higher tempera- 
tures; but when we make a similar comparison for the east of America 
snd the east of Asia, the higher temperatures are found in America. 
56. By way of illustrating these great general facts by neans 
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CLIMATE