C 29 ] 



TIJJE opinions of Wolterfdorf are principally thefe : 



That Soil proceeding from vegetable or animal fubftances paiTes 

 gradually into clay, n. 6. ; but jthis appears to vvant demon- 

 ftration. 



That all Rock, when (ilruck againft fleel, gives put fparks. 



That Pumice-ftone is not th.e product of volcanos, «. 14, 



That the Lapis atramentarius is produced by eroded vitriol, 

 n. 24. 



That Cobalt is of the farpe genus with arfenic, «. 30. 



That true native Iron no where exifts, 7?. 34. 



Jvinne \yas doubtlcfs the firft who, according to the laws of Syf- 

 tem, endeavoured to reduce the fcience of Mineralogy into 

 Clafles and Orders. Pref. 



fie divides Spar into three diftinft genera, or mqre properly into 

 three orders; Vitrefcent, Gypfeous, and Alcaline. 



