274 TERMINOLOGY. . 



varieties, as long as this composition had not been explain- 

 ed, nor the individuals themselves traced in it, whose di- 

 minutive size very often considerably adds to the difficulty. 

 If we consider the varieties of rhombohedral Iron-ore, or 

 of many other species, and if we do riot possess an exact 

 knowledge of the individual in the mineral kingdom, that 

 is to say, if we do not sufficiently distinguish between 

 simple and compound minerals ; we find some of them so 

 very different, that it would seem to be in opposition to all 

 the principles of Natural History, if nevertheless we would 

 unite them into one species, since they differ in almost 

 every one of their properties. This has indeed been the 

 reason why Specular Iron-ore, lied Iron-ore, and many 

 others, have really been considered and distinguished as 

 particular species. At that time the transitions (. 221.), 

 which might have led to the knowledge of errors commit- 

 ted in these determinations, had also not yet been dig- 

 tinctly developed ; and it must be avowed that those mi- 

 neralogists who have escaped similar errors, awe this 

 to inquiries and considerations of minerals, very different 

 from such as are carried on according to the principles of 

 Natural History. 



A few examples, once given of the dismemberment of a 

 natural-historical species, could not but produce many si- 

 milar errors in subsequent instances. The consequences 

 of this mode of proceeding, have been numberless species, 

 or aggregates erroneously so called, being connected Avith 

 each other by transitions. Incapable of being character- 

 ised, or distinguished from one another, they have only 

 served to incumber the nomenclature, and to degrade the 

 systems into mere registers of words. If one single erro- 

 neous idea is capable of producing such confusion, we must 

 bestow all possible attention on the establishment of cor- 

 rect ideas, in a science in which they are or might be so 

 pure and simple, as in the Natural History of the Mineral 

 Kingdom. 



Zoology and Botany have not been subject to similar er- 

 rors. They are almost impossible in the first, and in the 



