vi PREFACE. 



Mr- Saujfure, render his work, if ever it ap-* 

 pears, abfolutely unintelligible *. 



Whether the characters of Minerals fhould 

 be taken from external appearances only, or 

 from their internal properties as difcovered 

 by chymical agents, has long been contro- 

 verted among Mineralogifts ; though, in- 

 deed, at prefent the controverfy feems almoft 

 at an end from the univerfal approbation with 

 which the fyftem of the celebrated Cronfted, 

 founded almoft entirely on chymical charac- 

 ters as far as they were known in his time, 

 has been received by all Europe. However, 

 fome able patrons of the former opinion 

 have appeared of late, among whom I ihall 

 mention only Mr. Werner and Mr. Rome dc 

 Lijle. 



Mr. Werner is the author of an excellent 

 treatife written in the German language on 

 the external characters of foffils. Mr. Rome 

 has lately publifhed a voluminous treatife on 

 the external forms of cryftals, under which 

 title he comprehends all thofe foffils that are 

 fufceptible of a regular figure, all of which 

 he pretends may be diftinguifhed by the 

 angles which their planes make with each 

 pther, if fome heterogeneous matter be not 

 Contained in them ; but fuppofing all this to 



f Foyages fas Alps* p. 6 jr. 



be 



