of which ftands the imperial city of Goilar, fo famous
for its filver mines, where the loofened ftone may be ob-
ferved to crumble away, and be covered with mofs, and
verdure: infomuch that though the period is not yet arrived,
for its entire decompofition, foon, or late, it will
happen, and be covered with grafs, in the fame manner
as the mountain o f Hartz is at prefent.
Sit* About a quarter o f a league'from the city o f Molina, there is a fprrng whofc waters have
a fmell like rotten eggs, from being impregnated with fulphur an d a lk a li: thofe who-have aniu-
lyzed them, allure us, that they are o f the fame nature with the fprings near Gibraltar, and the
.waters o f Cotterets, in France, and equally ufeful in cutaneous complaints. The river Gallo
abounds in falmon trout, from half a pound to* four pounds weight. A bo u t a- quarter o f a
league from the town, the river contains a fine white earth m ixed in its waters, which incrufls
the earth and fuch plants as it touches, with a limy fubftance, though the water appears clear
.and limpid.
L E T T E R
L E T T E R X X II.
The fource o f the Tagus and its environs defcribed-
IN going from Molina de Aragon, to the weftward,
you crofs over mountains filled with petrifactions,
which appearance lafts for two or three leagues. At the
third league there is a fait fpring which ferves the people
o f Molina. The afcent is continual, through a wood
o f fir, and over mountains, till you reach the village o f
Peralejos on the banks of the golden Tagus, fo often
fung by the poets, fo frequently extolled by hiftorians.
At Peralejos, the Tagus is only fifteen paces wide, and
one foot deep. The petrifactions are obferved again in
the village, and the river runs through a narrow channel
it has made for itfelf, between two lofty mountains
Of marble, perpendicularly flitted near a hundred feet
high. Each mountain is a folid block, without either
horizontal, or perpendicular fiifure, if we except thofe
cafual crevices, occafioned by the enormous pieces which
now and then detach themfelves, and roll down to the
banks of the river. Such as have tumbled down on the
fouth