IN SIMPLE MINERALS. 
575 
The A theistical Theory assuming the gratuitous 
postulate of the eternity of matter and motion, 
Would represent the question thus. All matter, 
it would contend, must of necessity have assumed 
some form or other, and therefore may fortuitously 
have settled into any of those under Avhich it 
actually appears. Now, on this hypothesis, we 
ought to find all kinds of substances presented 
occasionally under an infinite number of external 
forms, and combined in endless varieties of in- 
definite 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 by cleavage and mechanical di- 
vision, without chemical analysis : the integrant 
molecules* of these primary fonns of 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 publi- 
cations ; 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 Evident, 
si, en penetrant dans le mccanisine intime de la structure, on 
0on9oit tous ces cristaux comme des assemblages de molecules 
integrantes parfaitement semblables par leurs formes, et subor- 
'lonnees, ^ un arrangement regulier. Ainsi, au lieu qu’une 
