INTRODUCTION. IX 



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of language, styled Sub-species, with still smaller divisions of 

 Varieties, and Sub-varieties; so there remains a necessity for 

 more minute discriminations in this new arrangement. In 

 his excellent and elaborate system of chemistry Dr. Thomson 

 seems to have hit upon the just and natural term, when he 

 uses the word ASPECT as a chief characteristic. " The parti- 

 cular characters, says he, are the following: 1. Aspect of 

 the surface 5 C Z. Aspect of the fracture ; 3. Aspect of the 

 distinct concretions - } 4. General aspect, &c." As therefore 

 the most important object in the study of minerals is to 

 distinguish them by their external characters, and especially 

 by those apparent to the eye, the aspect becomes of such 

 radical importance that it may with the greatest propriety 

 be admitted into the distinctive nomenclature. The verb 

 aspecto signifies to view with great attention or earnestness, 

 and affords a hint to the student that these subdivisions called 

 aspects require strict attention and discrimination. Thus, 

 while the Mode chiefly expresses the difference of chemical 

 composition, &c. and the Structure the grand characteristic, 

 the Aspect refers to more minute features. The term variety Varieties, &c, 

 is unobjectionable, as it is equally applicable to objects of ani- 

 mated orhiert matter j and diversity may be used to imply a 

 still greater difference than the variety presents. A very 

 faint shade of difference might, if necessary, be called a 

 lineament. 



Having thus briefly explained the present system, the 

 result of the reflections and meditations of many years (for 

 it is well known that simplicity in a plan, or a machine, as 

 it is the most perfect quality, so it is the last which is dis- 

 covered), it may not be unnecessary to illustrate its necessity 

 and utility by some further observations. 



The embarrassments of the former systems cannot be more 

 forcibly evinced than by the following discussion by Wer- 

 ner, in his important work on the External Characters of 

 Minerals. 



" I shall here add some remarks upon the division or natu- Werner's 

 ral order of bo'dies in general, as wejl for example, as expja- difficulties. 



