PRELUDE TO THE EPOCH OF DE LISLE AND HAUY. 317 



an opinion very natural in one who had been immersed in the study of 

 the general analogies of the forms of plants. But though this is ex- 

 cusable in Csesalpinus, the rejection of this definiteness of form a 

 hundred years later, when its existence had been proved, and its laws 

 developed by numerous observers, cannot be ascribed to anything but 

 strong prejudice ; yet this was the course taken by no less a person 

 than Buffon. " The form of crystallization," says he, 4 " is not a con- 

 stant character, but is more equivocal and more variable than any 

 other of the characters by which minerals are to be distinguished." 

 And accordingly, he makes no use of this most important feature in 

 his history of minerals. This strange perverseness may perhaps be 

 ascribed to the dislike which Buffon is said to have entertained for 

 Linnaeus, who had made crystalline form a leading character of mine- 

 rals. 



It is not necessary to mark all the minute steps by which mineralo- 

 gists were gradually led to see clearly the nature and laws of the fixity 

 of crystalline 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 remarkable 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, 6 in his Harmonics of the World, asserts a " forma- 

 trix facultas, which has its seat in the entrails of the earth, and, after 

 the manner of a pregnant woman, expresses the five regular geometri- 

 cal 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," that 

 though the sides of the hexagonal crystal may vary, the angles are not 

 chanyed. And Dominic Gulielniini, in a Dissertation on Salts, 

 published in 1707, says, 7 in a true inductive spirit, "Nature does not 

 employ all figures, but only certain ones of those which are possible ; 

 and of these, the determination is not to be fetched from the brain, or 

 proved a priori, but obtained by experiments and observations." And 



Hist, des Min. p. 343. ' Linz 1619, p. 161. 6 p. 69. T p. 19. 



