216 Biographical Memoir of M. Hauy. 



,it proved that, in fact, like calcareous spar, it only contains car- 

 bonate of lime. 



If the minerals which are properly determined with respect 

 to their species and composition, he now said, have each its nu- 

 cleus and its constituent molecule fixed, it must be the same 

 with all the minerals distinguished by nature, and whose com- 

 position is not yet known. This nucleus or molecule may 

 therefore supply the composition for the distinction of sub- 

 stances; and from the first application which he made of this idea, 

 he threw light upon a department of science which all the la- 

 bours of his predecessors had failed to elucidate. 



At this period, the most able mineralogists, Linnaeus, Wal- 

 ierius, Rome Dehsle *, and Saussure himself, confounded, un- 

 der the name of schorl^ a multitude of minerals, which had no- 

 thing else in common than some degree of fusibiHty, united to 

 a more or less prismatic form ; and under that of zeolite^ a mul- 

 titude of others, whose sole distinctive character was that of 

 being converted by acids into a sort of jelly. The schorls, espe- 

 cially, formed the most heterogeneous union : all the mine- 

 rals that were but imperfectly known, were thrown into them: 

 and the late M. de Lagrange, a man whose extensive know- 

 ledge and accuracy of perception equalled his genius, said in 

 jest, that schorl was the nectary of mineralogists, because 

 botanists were accustomed to designate as a nectary any part of 

 the flower of whose nature they were ignorant. 



M. Haiiy having divided mechanically the substance called 

 white schorl^ was quite astonished to find in it the nucleus and 

 molecule of felspar +. The late M. Darcet, analyzing it on 

 this indication, in fact, discovered in it all the physical and che- 

 mical characters of the felspars. 



Filled with new hopes, M. Haiiy examined the other schorls^ 

 and discovered that the black mineral which occurs imbedded 

 in so many lavas, and which was named volcanic schoil^ has 

 for its nucleus an oblique prism with rhombic base, and that 



• Cristallographie, tome ii. p. 344, et seq. 



■J" Notice res})ecting white schorl^ read to the Acadeinj- on the 28th July 

 1784, printed in the Journal de Physique of 17B6, torn. i. p. 63; and, in 

 1787, in the Memoirs of the Academy for 1784, p. 270. 3 



