Mineralogist has ascertained that Granite is a
compound substance, made up of three distinct
and dissimilar simple mineral bodies, Quartz, F e lspar,
and Mica, each presenting certain regular
combinations o f external form and internal structure,
with physical properties peculiar to itself.
And Chemical Analysis has shewn that these several
bodies are made up o f other bodies, all o f
which had a prior existence in some more simple
state, before they entered on their present union
in the mineral constituents o f what are supposed
to be the most ancient rocks accessible to human
observation. The Crystallographer also has further
shewn that the several ingredients o f Granite,
and o f all other kinds o f Crystalline Rocks are
composed o f Molecules which are invisibly minute,
and that each o f these Molecules is made
up o f still smaller and more simple Molecules,
every one o f them combined in fixed and definite
proportions, and affording at all the successive
stages o f their analysis, presumptive proof that
th ey possess determinate geometrical figures.
These combinations and figures are so far from in dicating
the fortuitous result o f accident, that they-
are disposed according to laws the most severely
rigid, and in proportions mathematically exact.*
The above Paragraphs of this Chapter excepting the first,
are taken almost verbatim from the Author’s MS. Notes of his
Lectures on Mineralogy, bearing the date of June 1822, and
he has adhered more closely to the form under which they ap-
The Atheistical Theory assuming the gratuitous
postulate o f the eternity o f matter and motion,
would represent the question thus. All matter,
it would contend, must o f n ecessity have assumed
some form or other, and therefore m ay fortuitously
have settled into any o f those under which it
actually appears. Now, on this hypothesis, we
ought to find all kinds o f substances presented
occasionally under an infinite number o f external
forms, and combined in endless varieties o f indefinite
proportions ; but observation has shewn
that crystalline mineral bodies occur under a
fixed and limited number of external forms called
secondary, and that these are constructed on a
. series of more simple primary forms, which are
demonstrable b y cleavage and mechanical division,
without chemical analysis : the integrant
molecules* of these primary forms o f crystals are
pear, than he might otherwise have done, for the sake of showing
that no part of them has been suggested by any recent publications
; and that the views here taken have not originated in
express considerations called forth by the occasion of the present
Treatise, but are the natural result of ordinary serious attention
to the phenomena of Geology and Mineralogy, viewed in their
conjoint relations to one another, and of enquiry pursued a few
steps further beyond the facts towards the causes in which they
originated.
* Ce que j ’ai dit de la forme deviendra encore plus évident,
si, en pénétrant dans le mécanisme intime de la structure, on
conçoit tous ces cristaux comme des assemblages de molécules
intégrantes parfaitement semblables par leurs formes, et subordonnées,
à un arrangement régulier. Ainsi, au lieu qu’une