he southern limit of the S. E.
trades travel in like manner with the rainy belt, or rather, to speak with
entire accuracy, the belt of rain moves with the trades, and the trades
follow the verticality of the sun. The following diagrams exhibit
approximately, and with sufficient accuracy for illustration, the
situations of the rainy belt and the trades, when at their northern and
southern limit, as well as the manner in which it must give certain
localities two rainy seasons each year, in its transit north and south.

At the northern and southern limits of the trade-winds, and extending from
them to the poles, are found the variable winds and irregular
extra-tropical rains, all over the earth, which are shown by the shading
on the maps. This line of extra-tropical rains descends to the south,
following the retreating trades as they descend in our winter, and recedes
north before the trades when they return in spring and summer, so that at
the outer limit of the trades respectively, toward the poles, the line of
extra-tropical rains will be found, receding or following that limit, as
the trades pass up and down with the sun. From the north pole to the
northern limit of the N. E. trade-winds, wherever found, whether at 38 deg.
north latitude, as in some places in summer when the sun is at the tropic
of Cancer; or whether at 20 deg. to 30 deg. north latitude, as in our winter, when
the sun is at the tropic of Capricorn; the extra-tropical rains prevail. A
state of things precisely similar exists between the south pole and the
southern limit of the S. E. trades. Between this northern limit of the
N. E. trades and the northern line of the inter-tropical belt of
rains, wherever situated (with two exceptions, to which we have alluded
and shall allude again), there is, for the time being, a dry season; and a
like dry season between the southern line of the belt of rains and the
southern limit of the S. E. trades. We have, therefore, extending around
the earth, a belt of daily tropical rains, near the center,--two belts of
drought which are mainly trade-wind surfaces, one on each side of the
central rainy belt,--extending to the outward limits of the trades and the
line of extra-tropical rains; and these rainy and dry belts, moving up and
down after the sun, a distance of from twenty to forty degrees of
latitude, each year.

[Illustration: Fig. 10. IN SUMMER.]

[Illustration: Fig. 11. IN WINTER.]

Such are the _main_ pheno