Acosta is very hazy on the subject. Cieza de Leon comes nearer the true cause, which is of course due to the height of the Andes. For the south-east trade-wind blows obliquely across the Atlantic Ocean until it reaches the coast of Brazil, heavily laden with moisture. It continues to carry this moisture across the continent, depositing it as it proceeds, and filling the tributaries and sources of the Amazon and La Plata. Eventually this trade-wind reaches the snow-capped mountains of the Andes, and the last particle of moisture is wrung from it that the very low temperature can extract. Meeting with no evaporating surface and with no temperature colder than that to which it was subjected on the mountain tops, the trade wind reaches the Pacific Ocean before it again becomes charged with fresh moisture. The last drop it has to spare is deposited as snow on the tops of the mountains. It reaches the coast region as a perfectly dry wind.
Yet the coast atmosphere is not absolutely dry. There is intense heat and a clear sky from November to April, but in May the scene changes. A thin mist arises which increases in density until October, rising in the morning and dispersing at about 3 P.M. It becomes fine drizzling rain called garua. This garua extends from the seashore to near the mountains, where rain commences, the line between the garua and the rain region being distinctly marked. There are even estates where one half the land is watered by garuas, the other half by rain. But the prevailing aspect
