The morning star and Catholic messenger., 1877-05-20
LANDS BELOW TIE OCEAN LETEL.
IScientifc American. i

IScientifc American
In an article treating OF some remark
able results of evaporation and rainfall, W
Edescribed one of the instances of the grea
excesses of evaporation over rainfall
namely, the Caspian Sea, of which tb
surface is much below the ocean level a
our Lake Champlain is above the same
namely, more than 80 feet. There are
however, two still more remarkable case
of the same sort, the Dead Sea in Palestin,
and the Great Desert of Sahara in Africa
The former ia remarkable for the grea
amount of the depression, and the latte
for the immense surface depressed, beiDe
in fact the bottom of an immense inland
lake, totally dried up by the heat of a trop
ical climate, aided by the absence o
feeding streams, and by the rainless ares
which covers its greatest portion. 1t is
on en- average, 80 feet below the ocean
about as much as the Caspian Sea; or nearly
1000 miles square, or nearly 4OO000C
square miles.
The French government, having ar eye
to the colonization of Northern Africa,
with Algiers as q starting point, has for
some time ia 7ored project for restOring 6
this sandy waste to it's priDeval condition
by cutting communication with the ocean,
and so Transforming it into q salt water
inland lake. The effect of this on the eli
mate of the surrounding country, and es-
pecially on the colony of Algiers, would
undoI billy be most beneficial, because the
south wind, instead of blowing as it does
now, over a sandy desert, would become a
sea breeze; this would increase the rainfall,
and change rainless district into fruit
ful region. In a commercial point of view,
moreover, the benefits of such change
could not be overestimated. The introduc-
tion of water transportation is especially
advisable in this tropical region, where the
miserable and utterly inefficient caravan
is now the only mode of carrying goods;
and without doubt commercial cities
would soon spring up around the shores
of the proposed inland sea, which would
become the scene of a mighty travel and
traffic, as the lake would give easy access
to the surrounding countries and develop
this part of Africa to al extent thus far
utterly undreamed of.
But it is well to look also at the disadvan-
tages of thIs gigantic scheme. la the first
place, it will rob the ocean of such an enor-
nous amount of water that it's general
surface will be lowered to an appreciable
extent. In order to realize how much this
lowering will amount to, let us consider
that the total Terrestrial surface is, in round
numbers 300, ,00U 600, square miles, of!which
the ocean occupies three quarters, or l5O,
900 600. If the estimate given of the De-
sert OF Sahara, 4,0OO, 600 square miles, is
correct, it occupies one-thirty. eight part of
the oceans surface, and, therefore, every
foot of depth of water abstracted for the
Desert will diminish the ocean one-thirty-
eight part of foot; aAd the withdrawal of
water for lake eighty feet deep would
the o"ean level go < one-t thirty eight, or
more than two feet lower, which would be
plainly perceptible in the many harbors
where careful tiding observations are made
and in some cases changes may influence
the shipping, robbing as it would do all
parts of TIE world of over two feet depth of
h. IL -,,lI L. L.
localities where the harbOrs are shallow.
- This much as to an immediate result; but
the ultimate consequences would be much
more serious. 1t should be considered that
this large inland lake, if once esta blished,
would have no fresh water supply, by Iivere;
but the sea water would certainly rush in
through the channel, to make up for the
large evaporation, which we may safely
set down at !, 200 lbs. of water per year for
every square foot. This would lower the
level 90 feet per year, which is one quarter
Of the whole quantity of the lake. This,
for surface of A 100000 square miles, or
LOG, 600 ,0O0, 900 900 square feet, gives g.
DOC, 600 600 000, ,090 cubic feet of water to
be replaced annually from the ocean, or
nearly 5000, 900. .OOO, 900 cubic feet per day,
or $50 600 OOO, 900 cubic feet per hour. or
| 166 666, ,666 cubic feet per minute, or &c. |
l44, ,444 cubic feet or 525 900, 900 gallons
per second. As the German Rhine carries |
>nly 1,OOO,UO gallons or water per secono, |
IN an average, the channel bringing the |
Jupply to the Desert Of Sahara from the
ocean would have co carry as much water |
ss is carried by 525 rivers like the r line
md from the salt water only pure water |
gould be evaporated, leaving the salt be-
lind. AS this amounts to 4 per cent, or
25 of the sea water, and as nearly 90 |
cot deep, or of the water in this new
AXE, would annually evaporate, it would |
,nly take 4x25. or 100 years, one single |
for all the water so disappear, and |
deposit of salt take its place. Then the
low andy desert would be changed into
leser5 of salt which salt would fill the
whole basin. and would certainly be more
erious atfliction to Algeria than the
present sand plain can possibly be.
STORY OF 4 NOSE,