PRELUDE TO THE EPOCH OF HAUY. 217 



of minerals. This strange perverseness may 

 haps be ascribed to the dislike which Buffon is said 

 to have entertained for Linnaeus, who had ma^le 

 crystalline form a leading character of minerals. 



It is not necessary to mark all the minute steps 

 by which mineralogists were gradually led to see 

 clearly the nature and laws of the fixity of crystal- 

 line forms. These forms were at first noticed in 

 that substance which is peculiarly called rock- 

 crystal or quartz ; and afterwards in various stones 

 and gems, in 'salts obtained from various solutions, 

 and in snow. But those who observed the remark- 

 able regular figures which these substances assume, 

 were at first impelled onwards in their speculations 

 by the natural tendency of the human mind to 

 generalize and guess, rather than to examine and 

 measure. They attempted to snatch at once the 

 general laws of geometrical regularity of these 

 occurrences, or to connect them with some doctrine 

 concerning formative causes. Thus Kepler 5 , in his 

 Harmonics of the World, asserts a "formatrix 

 facultas, which has its seat in the entrails of the 

 earth, and, after the manner of a pregnant woman, 

 expresses the five regular geometrical solids in the 

 forms of gems." But philosophers, in the course of 

 time, came to build more upon observation, and less 

 upon abstract reasonings. Nicolas Steno, a Dane, 

 published, in 1669, a dissertation De Solido intra 

 Solidum Naturaliter contento, in which he says 6 * 



5 Linz. 1619, p. 161. 6 p. 69. 



