458 OBJECTS AND METHOD OF MINERALOGY. [XIX. 



which Nature builds up her units, by interpenetration and 

 identification, and not by juxtaposition of the chemical ele- 

 ments. 



None of the above points are presented as new, though they 

 are for the greater part, I believe, original with myself, and 

 have been from time to time brought forward and maintained, 

 with numerous illustrations, chiefly in the American Journal 

 of Science, since March, 1853, when my paper on the Theory 

 of Chemical Changes and Equivalent Volumes (ante, page 426) 

 was there published. I have, however, thought it well to pre- 

 sent these views in a connected form, as exemplifying my 

 notion of some of the principles which must form the basis 

 of a true mineralogical classification. 



