Alpena weekly argus. [volume] (Alpena, Mich.) 1871-1893, 1892-12-07
Sahara.

The Sahara is an immense zone
of desert which commences on the
shores of the Atlantic Ocean, be-
tween the Canaries and Cape de
Verde, and traverses the whole of
North Africa, Arabia, and Persia,
as far as Central Asia. The Medi-
terranean portion of it may be said
roughly to extend between the 18th
and Both degrees of north latitude.
This was popularity supposed to
have been a vast inland sea in very
recent times, but the theory was
supported by geographical facts
wrongly interpreted. 1t has been
abundantly proved by the researches
of travellers and geologists that such
sea was neither the cause nor the
origin of the Libyan Desert.
Rainless and sterile regions of
this nature are not peculiar to
North Africa, but occur in two
belts which go round the world in
either hemisphere, at about similar
distances north and south of the
equator. These correspond in To-
cality to the great island drainage
areas from which no water can be
discharged into the ocean and which
occupy about one-fifth of the total
land surface of the globe.
The African Sahara is by no
means a uniform plain, but forms
several distinct basins containing
a considerable extent of what may
almost be called mountain land.
The Hoggar mountains, in the cen
ter of the Sahara, are 1000 feet
high, and are covered during three
months with snow. The general
average may be taken at l,500.
The physical character of the regi Oh
is very varied. In some places.
such as Tout, Touat, and other
oases in or bordering on Morocco,
there are well-watered valleys, with
fine scenery and almost European
vegetation, where the fruits of the
North flourish side by side with the
palm tree. In others there are riv-
ers like the Uied Guir, an afiluent
of the Niger, which the French
soldiers, who saw it in 1870, COM
pared to the Loire. Again, as in
the bed of the Uied Guir, there is
subterranean river which gives
sufficient supply of water to make
a chain of rich and well-peopled
oases elual in fertility to some of
the finest portions of Algeria. The
greater part of Sahara, however, is
hard and undulating, cut up by dry
water courses, such as the Ighar-
CHAR, which descends to the Chott
Melghigh, and almost entirely
without animal or vegetable life.
About one-sixth of it's extent
consists of dunes of moving sand,
a vast accumulation of detritus
washed down from more northern
and southern regions--perhaps
during the glacial epoch---but
with no indication of marine form
alton. These are difficult and even
dangerous to traverse, but they are
not entirely destitute of vegetation.
Water is found at rare but we'll
known intervals, and there is abund-
ance of salsolaceaus plants which
serve as food for the camel. This
sand is largely produced by wind
action on the underlying rocks,
and is not sterile in itself-it is on
ly the want of water which makes
it so. Wherever water does exist,
or artesian wells are sunk, oases of
great fertility never fail to follow.
Some parts of the Sahara are be-
low the level of the sea, and here
are formed what are called chotts or
sebkhas, open depressions without
any outlets, inundated by torrents
from the southern slopes of the At
las in winter and covered with a
saline efflorescence in summer.
This salt by no means proves the
former existence of an inland sea.
1t is produced by the concentration
of the natural salts, which exist in
every variety Of soil, washed down
by winter rains, with which the un-
eyaporated residue of water becomes