
deep as you pleafe, and never find any thing but gypfum,
which is very feldom feen where there is mineral.
The country, is every where barren and miferable, a
perfe<ft defert without water, and nothing but rofemary,
lavender, and a few ftarved oaks. After quitting this
wretched diftrift a fertile plain opens to the eye, fuppli-
ed by wheels with water from the Ebro, and here I faw
the tamariik, which is a beautiful plant when in flower.
From Caparrofo it is four leagues to the Ebro in a
plain bordered by a chain o f hills from eaft to weft,
■compofed of limy earth mixed with gypfeous ftone,
fometimes in ftrata, granulated, or in mafies, white as
fnow. This chain extends about two leagues, and towards
the middle, where it is the higheft, ftands the village
of Valtierra: about half way up, there is a mine of
foffil common fait, which being tranfparent and refemb-
ling chryftal, goes by the name of Salgem, and is feen
above ground where the ihaft is made at the entrance of
the mine. About twenty paces within, one obferves that
the fait, which is white and’ abundant, has penetrated
into the very beds of gypfeous ftone. This mine may
be about four hundred paces in length, with feveral lateral
ihafts, upwards of eighty paces, fupported by pillars
o f fait, and gypfum, which the miners have very judici-
oufly left at proper diftances, fo that it has all the appearance
of a gothic cathedral. The fait follows the
dire&ion
direction o f the hill, inclining a little to the north, like
the ftrata o f gypfum, being comprifed in a fpace about
five feet in height without variation, and feems to have
corroded feveral beds of gypfum, and marl, and infinu-
ated itfelf into their place, though much of thofe fub-
ftances ftill remain.
At the end o f the principal ihaft, the miners have
carried out a branch to the right, where the faline bed
appears to have followed exaftly the inclination o f the
MIT, which in that part is very perpendicular: this firatum
o f fait defcends to the valley, and goes on to the oppo-
fite h il l; which regularity deftroys the fyftem o f thofe
who pretend that fal gem is formed by the evaporation
occafioned by fubterraneous fire. I f this was the cafe,
the beds would not be undulated in this manner, re-
fembling thofe of coal at Chamond, near Lyons, in
France, or thofe o f afphaltos (a), in Alface, that follow
the elevation and declivity of the hills or vallies, the b i-
(a) Afphaltos or JewiJh bitumen is fo called from the lake AfpKaltites or dead'fea in Judea,
•which rifes up in the nature of a liquid pitch, and floats upon the furface of the water like
other oleaginous bodies, and is condenfed by degrees through the heat of the fun ; the Jews
formerly ufed'it to embalm their-dead. The Arabs gather it for pitching their ihips, but-
Europeans ufe it in. medicinal compolitions, efpecially in theriaca, or Venice treacle \ as alfo
a:fine black varnifli, in imitation of.that of China. Rolt’s did; of commerce. London, 1.7 61.
The origin of bitumens is aninterefling queftion, concerning which naturalifts are not agreed,
fome imagining that they eflentially belong, to the mineral kingdom, and otheis-that they
proceed originally from vegetable fubfiances; we.muft allow this latter opinion .to be the moil-,
probable, See. See did; of chemiftry, tranflated from the French. London, printed fox.
X Cadell, 1777..
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