is bathed by warm seas full of flying-fish and coral reefs. The
northern continent is broadest in the cool latitudes that are
most favorable for human activity. The southern expands most
widely in latitudes whose debilitating monotony of heat and
moisture is the worst of handicaps to human progress. The great
rivers of the northern continent correspond very closely to those
of the southern. The Mackenzie, however, is bound in the rigid
bands of winter for eight months each year, while the Orinoco,
the corresponding South American river, lies sweltering under a
tropical sun which burns its grassy plains to bitter dust even as
the sharp cold reduced the Mackenzie region to barren tundra. The
St. Lawrence flows through fertile grain fields and the homes of
an active people of the temperate zone, but the Amazon winds its
slow way amid the malarious languor of vast tropical forests in
which the trees shut out the sky and the few natives are
apathetic with the eternal inertia of the hot, damp tropics.

Only when we come to the Mississippi in the northern continent
and the Rio de la Plata in the southern do we find a pair of
rivers which correspond to any degree in the character of the
life surrounding them, as well as in their physiographic
character. Yet even here there is a vast difference, especially
in the upper courses of the river. Each at its mouth flows
through a rich, fertile plain occupied by a progressive,
prosperous people. But the Rio de la Plata takes its rise in one
of the world's most backward plains, the home of uncivilized
Indians, heartless rubber adventurers, and the most rapacious of
officials. Not infrequently, the degenerate white men of these
regions, yielding to the subtle and insidious influence of the
tropics, inflict the most outrageous abuses upon the natives, and