442 APPENDIX ON 



Mr. P. for the forms and measurements of crystals 

 which I had not myself previously examined. 



Following this alphabetical list, will be found a 

 second table of primary forms, arranged according to 

 their classes. 



The synonyms have been collected chiefly from 

 Leonhard's Handbuch der Oryktognosie, published 

 in 1821, and corrected from such other sources as I 

 have had an opportunity of consulting. The choice 

 of a specific name among many synonyms, has been in 

 some degree arbitrary, but I have generally been 

 influenced in this choice by the previous adoption in 

 this country of the name I have selected. On refer- 

 ing to the list, the word Abrazite will be found at its 

 head, with a reference to Zeagonite, that being the 

 name under which the mineral, also called Abrazite 

 and Gismondin, had been previously known here. 

 For this reason I have retained many of the old 

 names, as Chiastolite, for example, instead of Made, 

 the name assigned to the same mineral by Hatty. In 

 many instances, it will be perceived, I have adopted 

 the names given by Haiiy, either because they have 

 already become familiar to the English mineralogist, 

 as Peridot, instead of Chrysolite, or because they 

 have comprehended several of the older species under 

 a single name, as Amphibole, which includes the 

 Hornblende, Tremolite, and Actynolite of the Wer- 

 nerian school. 



Although the basis of the proposed arrangement of 

 minerals is alphabetical, it is to a certain extent 

 founded on their chemical distinctions. 



But a difficulty presents itself when we attempt a 

 purely chemical classification of minerals, which 

 arises out of the uncertainty of our knowledge rela- 

 tive to the essential constituents of many species. For 

 however accurately these may have been analysed by 



