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tacked, and did not melt in the ftrongeft
fire alone. The fufible urinous fait
hardly attacked it,; borax diflblved it,
though with difficulty ; but fal fodæ
diflblved it perfeffly with a ftrong ef-
fervefcence. In confequence of this
the gelatinous fubftance chiefly confifts
o f filiceous earth expanded in the
higheft degree. But by what means has
this indiflbluble fubftance been introduced
into a folvent ?
We have before obferved, that the
Adelfors zeolite contains eighty parts
in a hundred o f filiceous earth, nine
and a half o f argillaceous earth, and
fix and a half of calcareous earth free
from fixed air ; all which fubftances
are united as clofe as poffible. I f
therefore the powder is thrown into
an acid, and remains there during
fome time, the argillaceous and calcareous
earths are immediately attacked
by it ; but thefe are internally conr
iiefled with the filiceous earth, and
confequently take a confiderable part
o f it, half diíTolved, into the fpungy
and ftvoln ftate, which all fubftances
generally exhibit in the moment of
'C C Î 1pitar
precipitation. The fame thing happens
when a refinous gum is laid
into fpirits o f wine ; part o f the gum,
together with the refin, is then im-
mediately diflblved by the fpirit of
wine on account o f its conneclion,
though the firft alone cannot be dif-
folved by it at all. I f a fufficient
quantity o f water or acid is added
before the liquor begins to congeal,
no congelation enfues, but the filiceous
earth falls in loofe flakes to the
bottom, which evidently proves that
the folvent, in regard to its quantity
and ftrength, muft be confined within
certain limits. An addition o f ibme
chalk increafes its tendency to gelatinous
congelations, partly becaufe the
folution becomes more broken and
hard, and partly by means of bubbles
of fixed air, which attach themfelves
to the fpungy iiliceous powder, and
make it lighter ; whence the zeolite
of Adelfors in this cafe feems to liave
an advantage over every other fort,
on account of the lime-fpar naturally
mixed with it ; the principal part
however, no doubt, depends on the
A a 4 feveral
.•y
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