Evening star. [volume] (Washington, D.C.) 1854-1972, 1900-07-07
THE DESERT OF SAHARA
WHAT THIS GREAT WASTE OF LAM
REALLY IS.
HOW the Caravans Find Their Way
Across It-harks Left by CameIs
Effect of Storms
From the Scientific American Supplement-

From the Scientific American Supplement-
Inc ground presents great variety in COM
position and aspect. 1t would be an exag-
.seration to claim that the Saharian land
scapes are not monotonous. To the south
Oh Algeria comes first the Great Erg :p;J
miles in width. Every region of dunes is
called "Erg.' The Great Erg is the vastest.
When We enter this we meet in the frs,
place only with low, sandy promontories
which spread. undulated and striated over
the calcareous carapax of the naked soil
Farther on. the dunes increase in number
and size Sand is everywhere. and forms
both the apparent relief and the mass of
the ground. A complete geography is mold
ed IN this sand. There is Erg, properly So
called, with its hills. its chains it's counter
ioits' It's decIlVltles. its valleys, its deprcs-
sicns an0 its accidents of all sorts The en-
tre surface OF the bottoms is Slightly
honeycombed. The surface of the slonas is
wonderfully even and smooth. The ton OF
the highest dunes-the Oghroud plural of
Ghourd)-domlnates a chaos of ridges neaks
and depreSsions
The Light is dazzling and the sand never
appears white. The SUBMITS whicn are
either sharp or rounded. exhibit orange vel
low or rose-colored reflections The shad-
ows are of deep violet. Here and there
are seer black spots formed by tufts of
grass or shrubs. When the tufts of grass
are not too widely spaced the place where
they grow is called a pasturage
Inc tfaI tMedJebeD of the caravans
through the dunes is clearly written in the
sand, wherever the wind has not blown
since the last of them passed. Even after A
violent wind the Medjebed is still to be
seen In places where travelling is frecueut
me feet OF the camels pack the sand and
| their teeth leave mark in the sparse vege.
tation Of the road
| The ahorigines are endowed to the highest
| n .,tr-..a Nx-i-A
\ They are capable of distinguishing from
| each other dunes that to US look precisely
| alike. and recognize the highest of tham
| from afar and use them as datum points
| 1t is pCpu.arly supposed that these masses
| or sand are necessarily in motion. in
| reality. the displacements produced by
| the wind are continuous. but not
| very perGeptble When the Chill
| b ows yellowish dust is seen to fly from
| the crests. This dust. which is sand, is
| carried to great distance; but one tenn
pest restores as much of the material as an
| other one has carried away, and so a bal
ance Is established. The volume of each mass
scarcely changes except as the result Of
| exceptiona, whrlwinds or Of feeble but
constant actions. The wind affects merely
| the superficial strata and modifies the nm
dulations OF the burrows only. AS a whole
the chains Of dunes are as stable as noun
tain chains. The largest of them have
| names that they received hundreds of wears
ago, and that they will continue to bea r
| for ages to come
| storm of extreme violence came down
\ upon Timassanine in the month of Decem-
| Der. 1898 and lasted three days There was
so much sand in the wind that the air wa G
darkened by it. and the fine dust was hur ed
with violence against the adobe walls of
| the place After the Chilli had abated the
layers Of accumulated sand were measured
and found to vary from three and one-nuar
ter inches to five feet in thickness But
around the station the outlines of the I'M
duIatlons OF the ground had not undergone
any perceptible alteration.
Marching in the dunes presents other dIf-
ficulties than those that attend the ascer-
| tanning Of ones bearings A caravan, in
order to surmount a hi lock selects pa h
midway between the top and bottom, in
| order to avoid too steep an ascent and de-
| scent. The men of the vanguard and the
guides provided with mechara go on foot
| In traversing the Sandstone of them bare
| footed and others wearing Gourarian Shoes
wide and light and having felt soles. They
| walk little to the front and upon the
| flank of the group of camels- The latter
proceed with their usual calm step. sway
Ing their heads and occasionally making a
| snap with their teeth at the too rare grass
| IS that chance to be within their reach
| When a passage presents itsef where the
| soil Is particularly loose, the intelligent
| animals stop and make a careful inspection
| of the place, for they know that II they
/ pass In a body slide might occur along
| the decivity. So they separate one after
| another. in order to cross the pace one at
| time
| Camels. the pack animals especially have
| a repugnance toward climbing, and a great
| er one still toward descending. When they
are forced to approach a dune and to scale
| 1t, battle almost always ensues at the
| summit between them and their drivers in
| the attempt to make them descend on the
| other side: and in order to maintain them
| selves in the horizontal. they obstinately
| turn to the right and left. The mechara
pass more easily; and as for the horses
| they cheerfuhy climb hills and willingly
| descend them by sliding.
| The caravans that traverse the Great Ere
| from north TO south do not continue ly
| Is traversed by the Gassis-wide and
| lengthy passageways running north and
south. The soil of the Gassi is the Reg-a
| sand. which forms the best of all grounds
| the desert.
| In the medan part of the Gassi we fire..
| quently meet with what are called Dallas
low bottoms in which humidity accumu ties
| as a consequence of rains and keeps up the
| vegetation. The Dhamran, which the cam
| els eat with avidity; the Retem. on the flow.
| ers of which they browse. and the Zita
| which is used fuel. abound in this clayey
| or chalky soil, while the gum trees reach
| fine proportions therein.
| Other depressions contain deposits OF
gypsum and rocksa't. These are the Sch.
khas- The Foureau-Lamy mission met with
one Of them on leaving the Great E,rg near
| Ell Biodh- From the summit of the dunes
there was observed what might have beer
| supposed be frozen lake coyerad uyitb