The Abbé Durand has likewise testified that if the temperature does
not drop below 25 degrees Centigrade, it never rises above 33
degrees, and this gives for the year a mean temperature of from 28
degrees to 29 degrees, with a range of only 8 degrees.

After such statements we are safe in affirming that the basin of the
Amazon has none of the burning heats of countries like Asia and
Africa, which are crossed by the same parallels.

The vast plain which serves for its valley is accessible over its
whole extent to the generous breezes which come from off the
Atlantic.

And the provinces to which the river has given its name have
acknowledged right to call themselves the healthiest of a country
which is one of the finest on the earth.

And how can we say that the hydrographical system of the Amazon is
not known?

In the sixteenth century Orellana, the lieutenant of one of the
brothers Pizarro, descended the Rio Negro, arrived on the main river
in 1540, ventured without a guide across the unknown district, and,
after eighteen months of a navigation of which is record is most
marvelous, reached the mouth.

In 1636 and 1637 the Portuguese Pedro Texeira ascended the Amazon to
Napo, with a fleet of forty-seven pirogues.

In 1743 La Condamine, after having measured an arc of the meridian at