xviii PREFACE. for mineralogy this accomplilhed and moft amiable man was removed from this tranfient fcene before he was permitted to communicate to the world the re- fults of his own profound obfervations and thoughts, on a fcience in the knowledge of which he was only rivalled by its great founder Werner. Previous to entering on the defcription of the indi vidual minerals, I fhall, in the Introduction, firft date the bafts on which this fyftem is founded ; then men tion the method followed in fubdividing it into clafies, genera, fpecies, and fubfpecies, and give an account of the different characters employed in mine- ralogy, of the rules of mineralogical nomenclature; and, laftly, Ihew the utility of oryCtognofie and the requifites necefiary to form an oryctognoft. INTRODUCTION.