Saussure perceived no means for that introduction,
will appear from what immediately follows in that paragraph. "Ces rocs
auroient-ils ete detruits, ou bien ce spath n'est il que le produit
d'une secretion des parties calcaires que l'on fait etres dispersees
entre les divers elemens du granit?"

Had M. de Saussure allowed himself to suppose all those substances in
fusion, of which there cannot be a doubt, he would soon have resolved
both this difficulty, and also that of finding molybdena crystallized
along with feld-spar, in a cavity of this kind. sec. 718.

To this argument, taken from the close cavities in our agates, I am now
to add another demonstration. It is the case of the calcedony agate,
containing a body of calcareous spar; here it is to be shown, that,
while the calcareous body was altogether inclosed within the calcedony
nodular body, these two substances had been perfectly soft, and had
mutually affected each others shape, in concreting from a fluid state.
In order to see this, we are to consider that both those substances have
specific shapes in which they concrete from the third state; the
sparry structure of the one is well known; the spherical or mammelated
crystallization of the calcedony, is no less conspicuous; this last
is, in the present case, spherical figures, which are some of
them hemispheres, or even more. The figures which we have now in
contemplation are so distinctly different as cannot be mistaken; the
one is a rhombic figure bounded by planes; the other is a most perfect
spherical form; and both these are specific figures, belonging
respectively to the crystallization of those two substances.

The argument now to be employed for proving that those two bodies had
concreted from the fluid state of fusion, and not from any manner of
solution, is this: That, were the one of those bodies to be found
impressing the other with its specific figure, we must conclude that the
impressing body had concreted or crystallized while the impressed body
was in a soft or fluid state; and that, if they are both found mutually
impressing and impressed by each other, they must have both been in
the fluid and concreting state together. Now the fact is, that the
calcareous body is perfectly inclosed within the solid calcedony, and
that they are mutually impressed by each others specific figure, the
sparry structure of the calcareous body impressing the calcedony with
its type of planes and angles, at the same