The Ely miner., 1930-08-22
prepared by the National Geographic
Society. Washington, D. CD

" pun LHc great IlfcIS VI
i the world. OF the dozen larg-
est. six are in Asia and three
In Africa, leaving only three for the
two continents of the New world. And
among the twelve leaders, Europe and
Australia are wholly unrepresented.
The longest single river is the Nile,
measuring some 1000 miles from head
to mouth. The Nile is further distin-
guished In that it has no tributaries
for the last 1,5O0 miles of its course
to the sea. During this stretch it's
waters are considerably reduced in
volume by evaporation and irrigation,
so that it grows smaller instead of
larger toward its mouth.
Other African rivers among the
length-scoring twelve are the Niger
and the Congo. both fed by the trop-
ical rains of hot regions near the
Equator. In a general way they more
nearly resemble South Americas rep
resentative. the Amazon, than the
continents.
OF Asia's six longest rivers, four are
In Siberia, the OBJ, Yenisei and Lena,
flowing north into the Arctic ocean,
and the Amur emptying into an arm
Of the Pacific. The other two are the
Yangtze and Hwang, or Yellow, river
Of China.
These twelve river basins represent
the greatest variety Of climate and
civilization. The Amazon and the
Congo flow through lush equatorial
jungles inhabited by birds of brilliant
plumage, wild animals and savage
tribes, while the mouths OF the Ye-
nisei and the Lena are above the
northern timber line and their valleys
support the sparsest population. The
Mississippi and the Yangtze flow
through established, if divergent, civ
ilizations, with rich cities along their
banks like jewels on a string The
Nile is one of the cradles Of world
history; the Mackenzie is still a
frontier stream.
Five of the dozen rivers flow to the
north. These are the Nile, Mackenzie,
OBJ Yenisei, and Lena. The Missis-
sippi and Niger flow south. The
Amur, Yangtze, Hwang and Amazon
run eastward. Only the Congo points
toward the west.
Difference in Floods.
All these streams overflow their
banks at intervals but the results are
r,+,. rrol,, Il In fhsAfn Off I,n
Mississippi and the Yangtze, floods are
national disasters bringing untold suf-
fering to millions. The annual over
flow of the Nile with resulting ferti-
lization of the valley by the deposit
of silt is the source of the wealth of
Egypt The Hwang, or Yellow river,
from its habit of overflowing its banks
and changing its entire course at in
tervals is known as the 'scourge of
China"
The Amazon and the Congo lie al
most under the Equator, and the 9TH
er ten longest rivers are in the north
ern hemisphere. Four flow into the
Arctic ocean. A reason is not far to
seek. The greatest land masses are
in the northern half of the world, and
without large land areas long rivers
are impossible. The smaller conti-
nents of Australia and Europe are not
represented in the dozen. Similarly,
tie reason for the longest rivers flow
ing to the north and east is that the
longest continental slopes extend in
those directions.
The Yangtze and the Mississippi are
lined with wealthy cities largely be-
cause of their location in the temper
ate zone. The tropic Amazon, Niger,
and Congo are too hot; the Mackenzie
and the Siberian rivers are too cold
for the favorable growth of towns.
The Nile valley beyond Cairo is
mere strip of green from 10 to 80
miles wide between two burning des-
erts. The Hwang is too variable in
its habits to encourage navigation or
river ports.
From the earliest times these long
rivers have furnished high roads for
the exploration of continental interi-
ors. Nero sent an expedition to- dis
cover the headwaters of the Nile,
which failed to reach its objective.
Russian penetration of Siberia fol-
lowed the great river beds. The
Amazon and the Congo are still high
ways of discovery. Head reaches of
the Yangtze are yelled in Asiatic OBJ
scurity. The Niger was the river of
romance in the great days of Tim
buktu. The histories of the worlds
river basins have been the history of
the worlds empires. A great river is
both a roadway and source of life.
Menace of the Mississippi.
Although North America can claim
onlv two of the worlds dozen longest
rivers. it possesses in the Mississippi
Missouri the longest of them all.
This magnitude of the Mississippi is
becoming more and more of a menace
because each flood seems greater than
the preceding one. Why this should
be true has been a problem to some
laymen; but one of the chief factors
Is plain enough: it Is the usually laud-
able effort of Americans to develop
and build up their country.
Aside from the fact that several de
cades ago there were fewer people liv-
ing end fewer dollars invested in the
regions subject to overflow in the low
er Mississippi valley, the food stages