different, procefles, I never could difcover in it, the
leaft grain of fait, which perfuaded me that the fait
was entirely, decompofed by motion, and diffolved into
earth and water. The water of the Tagus, which
paffes between hills of gypfum.and fal gem, at Aranjuez,,
is bad in that fpot, but at Toledo it is good ; foap eaiily
diffolves in it, and a little lower down, if it is diftilled,
not the, leaft particle o f gypfum or fait is to be found(«)..
I f we burn fulphur, arfenic, pitch, or other combuftible)
matters at . the foot of a tower, none of thofe that are near
it can bear the ftench, while thofe above will not perceive, *
it ; becaufe it entirely ftecompofes into water and earth
before it reaches them, and the inflammable principle
which is inodorous rifes anew to form frefh combinations,
and occafion thunder and lightning, I fhould think the
emanations of malignant fevers, and o f the plague, follow
the fame laws.
It is commonly faid, that of the three acids .of nature,,
the nitrous, which is the fecond in ftrength, ejefts the.
marine, which is the third and the weakeft, but experience
is contrary to this do&rine, ft nee in Spain, the fal
gem ejecfts the nitrous acid from its bafts : grind twenty-
four ounces of this fait with twelve of falt-petre, let them
be diftilled in the ufual manner, and the refult will be a,
(a) Thefe curious fa£ts merit a further examination, as the prefen tilluftratiop is by no ipeans
fatisfaitory. _ , . .■ , . , • M
very
very good aquafortis, which will readily diffolve Giver,
and have no effetft upon gold. The ftlverfmiths o f Madrid
ufe no other. To clear up more fully this lingular
phenomenon, and fee whether the chemifts are miftaken
or not, nothing is left but to afcertain whether this fal
gem contains a vitriolic acid, becaufe in fuch cafe it would
not be the marine acid that was more powerful than the
nitrous, but the vitriolic: however as it has not been
demonftrated, or known, that any fuch vitriolic acid
exifts in common fait, the difficulty ftill remains. This
Angularity of the Spaniih fal gem merits the attention o f
chemifts and repeated experiments; as this fyftem feems
to militate againft the received opinions concerning the
nature of the three acids, the mafter-key o f chemiftry,
and overturns the theories now in vogue (a).
What rhapfodies have been publilhed with refpetft to
the phyfical caufes of the faltnefs o f the fea, fome faying
that immenfe beds of fait exifted at its bottom ; others,
finding this argument deftroyed itfelf, had recourfe to
the idea of rivers bringing down fait enough to the fea to
impregnate its waters, which fuppofition is as falfe as the
former, as we are pofitive that fea water is at prefent as
briny as it was in ancient times in proportion to its fitua-
(tz) Mr. Bowles feems to have drawn his concluiions rather too haftily, without refle&ing that
nitre when divided to & certain degree and kept divided, may by the force o f heat alone be
deprived of its acid; whilil common fait can fuflain a much greater degree o f heat without
any decompofition.
O d d tion,