INTRODUCTION. 381 
south-west monsoons ; but the former is the regular 
trade—the latter alone is the anomaly, and needs 
explanation. The cause usually assigned is, the 
rarefaction of the air on the continent of Asia 
during the summer months, when the sun is north 
of the equator; the air from the Indian Ocean 
flowing in to supply its place. This would sufii- 
ciently explain why the wind should be southerly, 
but leaves its westerly inclination entirely unac- 
counted for; and this seems the more inexplicable, 
because one would suppose that the air over the 
burning deserts of Arabia and North Africa would 
be much more heated, and that the direction of the 
supplying current would be south-east. Strange, 
however, as the fact is, it is perfectly uniform in 
its occurrence, and is obviously a very gracious 
ordination of God’s beneficent providence, in di- 
minishing the uncertainties of navigation. 
There is yet another phenomenon connected with 
the wind, in the climates of which we speak, that 
requires notice; it is the alternation of the land 
and sea-breezes. Every one who has resided near 
the coast in tropical countries is aware of the eager- 
ness with which the setting in of the sea-breeze is 
looked for. Usually about the hour of ten in the 
forenoon, when the heat of the sun begins to be 
oppressive, a breeze from the sea springs up, in- 
vigorating and refreshing the body by its delight- 
ful coolness, and continues to blow through the 
whole day, gradually dying away as the sun sinks 
to the horizon. Then, about eight in the evening, 
an air blows off the land until near sunrise; but this 
