C H A P . X.
O f the C rystall ization of S alts, As seen by the
Microscope; together with a concise L ist of
Objects.
/ c r y s t a l l i z a t io n , in general, fignifies the natural form-
, at*°.n ° f any fubftance into a regular figure, refembling that
o f natural cryftal. Hence the phrafes o f cryftallized ores, crvf-
talhzed falls, &c. and even the bafaltic rocks are now generally
reckoned to be effeHs o f this operation; the term, however is
moft commonly applied to bodies o f the falinekind; and their
reparation in regular figures from the water, or other fluid in
which they were dtffolved, is called their cryftallization. I f the
word cryftallization were to be confined to it’s moft proper fenfe
as it feems to have been formerly, it could only be applied to'
operations by which certain fubftances are difpofed to pafs from
a fluid to a fohd ftate, by the union o f their parts, which fo
arrange themfelves, that they form tranfparent and regularlyfigured
figured maffes, like native cryftal; from which refemblance the
word cryftallization has evidently been taken.*
But modern chemifts and naturalifts have much extended this
expreflion, and it now fignifies a regular arrangement o f the
parts o f any bo'dy which is capable of it, whether the maffes fo
arranged be tranfparent or not. Thus opake ftones, pyrites, and
minerals, when regularly formed, are faid to be cryftallized, as
well as tranfparent ftones and falts.
The opacity and tranfparency of fubftances are jufily disregarded,
in confidering whether they be cryftallized or n o t; for
thefe qualities are perfeftly indifferent to the regular arrangement
of the integrant parts of fubftances, which is the effential objeft o f
cryftallization.
This being eftablilhed, cryftallization may be defined, an
operation by which the integrant parts of a body, feparated from
each other by the interpofition o f a fluid, are difpofed to unite
again, and to form folid, regular, and uniform maffes.
T o underftand as much as we can o f the mechanifm of cryftallization,
we muft remark,
I. That the integrant parts o f all bodies have a tendency to
each other, by which they approach, unite, and adhere together,
when not prevented by an obftacle.
4 Q 2. That
* Macquer’ s Dictionary , of Chemiftry, Art, Cryftallization.