and give way to variable winds and calms. The trade-wind no
longer brings its regular supply of cooler, drier air; the rising
heats and calms favour an ascending current" (in the sea-depths,
I may add, as well as on land), "which bears the damp air into
the upper regions of the atmosphere, there to be cooled, and to
occasion the heavy down-pour of each afternoon. The nights and
mornings are for the most part bright and clear. When the sun
moves away from the zenith, the trade-winds again begin to be
felt, and bring with them the dry season of the year, during
which hardly ever a cloud disturbs the serenity of the skies.

"Between the tropical limits and the equator, however, the sun
comes twice to the zenith of each place. If now, between the
going and coming of the sun, from the Line to its furthest range,
a sufficient pause intervenes, or if the sun's temporary distance
from the zenith is great enough, the rainy season is divided into
two portions, separated by a lesser dry season. Closer to the
tropical lines, where the sun remains but once in the zenith, the
rainy season is a continuous one."

Such is the theory of the "Allgemeine Erdkunde" (Hahn,
Hochstetter and Pokorny, Prague, 1872). An explanation should be
added of the reason why the cool wind ceases to blow, at the time
when the air, heated and raised by a perpendicular sun, might be
expected to cause a greater indraught. We at once, I have said,
recognize its correctness at sea. The Gaboon, "in the belt of
calms, with rain during the whole year," has two distinctly
marked dry seasons, at the vernal and the autumnal equinoxes. The
former or early rains (Nchangya?) are expected to begin in
February, with violent tornadoes and storms, especially at the