ing south of the tropic of Capricorn.
In general terms, it is a tropical country, with sub-tropical and
temperate areas covering its three southern states and a great part of
the elevated central plateau. The forest-covered, lowland valley of
the Amazon is a region of high temperatures which vary little
throughout the year, and of heavy rainfall. There is no appreciable
change of seasons, except that produced by increased rainfall in the
rainy season. The average temperature according to Castelnau is about
78 deg.F., or 82.40 deg. to 84.20 deg. F. according to Agassiz. There
is an increase in the rainfall from August to October, and again from
November to March, the latter being the regular rainy season, but the
time varies considerably between the valley of the upper Amazon and
those of the upper Madeira and Negro. There is usually a short dry
season on the upper Amazon in January and February, which causes two
annual floods--that of November-December, and the great flood of
March-June. The subsidence of the latter usually lasts until October.
The average rainfall throughout the whole Amazon valley is estimated
by Reclus as "probably in excess of 2 metres" (78.7 in.), and the
maximum rise of the great flood is about 45 ft. The prevailing winds
in the Amazon valley are easterly and westerly (or south-westerly),
the former warm and charged with moisture, the latter dry and cold.
The easterly winds, which are deflections of the trade winds, blow
upstream with great regularity and force, more especially in the
winter or dry season, and are felt as far inland as the mouths of the
Madeira and Negro. Above these they are less regular and are attracted
northward by the heated _llanos_ of Venezuela in winter, or southward
by the heated _campos_ of Matto Grosso in summer. The cold
south-westerly winds are felt when the sun is north of the equator,
and are most severe, for a few days, in the month of May, when a
_tempo da friagem_ (cold period) causes much discomfort throughout the
upper Amazon region. There are winter winds from the Andes, but in the
summer season there are cold currents of air from up-river (_ventos da
cima_) which are usually followed by downpours of rain.

The coastal plain as far south as Santos is a region of high
temperatures and great humidity. The year is usually divided into a
winter (_inverno_) and summer (_verao_), corresponding appr