PRELUDE TO THE EPOCH OF HAUY. 221 



and to have introduced the word, is D&neste 12 ; 

 although Wallerius 14 had already said, in speaking 

 of the various crystalline forms of calcspar, " I coja- 

 ceive it would be better not to attend to all differ- 

 ences, lest we be overwhelmed by the number.'* 

 And Werner, in his celebrated work On the Exter- 

 nal Characters of Minerals 15 , had formally spoken 

 of truncation, acuation, and acumination, or re- 

 placement by a plane, an edge, a point, respectively, 

 (abstumpfung, zuschdrfung, zuspitzung,) as ways 

 in which the forms of crystals are modified and 

 often disguised. He applied this process in par- 

 ticular to show the connexion of the various forms 

 which are related to the cube. But still the exten- 

 sion of the process to the whole range of minerals 

 and other crystalline bodies, was due to Rome de 

 Lisle. 



13 Lettres, 1779, i. 48. 



14 Sy sterna Mineralogicum, 1772-5, i. 143. 



15 Leipzig, 1774. 



