314 THEORIES OF ORE DISPOSITION HISTORICALLY CONSIDERED. 



geological writers, especially those of the Wernerian school, is often 

 a cause of misconception among modern readers who have occasion 

 to consult the older works on geology and mineralogy. 



For over a century after Agricola there appears to have been little 

 written that had any special l)earing on ore deposits, but toward the 

 close of the seventeenth century there was an apparent awakening of 

 interest in regard to their origin among reflective men who had to do 

 directly or indirectly with mines, which may probably have been 

 promj^ted by the theories of the cosmic philosophers, so that by the 

 close of the eighteenth century there had accumulated considerable 

 speculative literature on this subject. 



The following is a list of the more frequently quoted works that 

 appeared during this period, with the approximate dates of their 

 publication : 



Speculum MetaUurgi;e politis.siinuui, by I'.ergmeister Balthasar Rfislpr (ITOU). 



Physiea subteiranea, by J. J. Becher. C'oimnentated by G. S. Stabl. Second 

 edition (1703). 



Pyritologia. by .J. F. Heiikel, ])rofes,s(ii- of cheiuistry and mineralogy, Freiberg 

 (1725). 



Obersjichsicbe Bergakademle. Ijy C. F. Zimmermann, councilor of mines 

 (1749). 



Markscbeidekunst, by \'on Oppel, vice-director of Saxon mines (1749). 



Abb. V. d. Metalmuttern, etc., by D. J. II. Lebman. director of I'russian mines 

 (1753). 



Elementa Metallurgi;e Cbemica>, by W. .1. Wallerius. Stockbolm (17G8). 



Ursprung d. (iebirge u. Erzadern, etc.. by C F. Delias, professt)r of metal- 

 lurgy at Scbenniitz (177U). 



Mineral, (ieograpli. d. KursJicbsisclie Lander, by J. F. W. de Cbarpentier, 

 director of Sa.xon mines (177S). 



Unterirdiscbe (Jeograpbie, by I. (i. Banmci-, (iiessen (1779). 



Geseh. d. Metallreicbs, by C. A. (ierbard, cduncilor of mines (1781). 



Erfahr. ii. d. Innern d. (Jel»irge, by F. M. 11. v. Trebra, vice-director of Han- 

 overian mines (17S.'')). 



Beobacht. ii. d. Hartz Gebirge. by Lieut, (i. O. S. Lasius, engineer on land 

 survey of Hanover ( 17S7). 



The views of most of these early writers were rather curious than 

 instructive, yet some of them, especially those of men who had the 

 largest practical experience in mines, are remarkably suggestive. 



Rosier, the earliest recorded mine superintendent, recognized that 

 veins differ from ordinary cracks in the rocks only by being filled 

 with metallic minerals, but did not speculate on their genesis. 

 Becher and his commentator, Stahl, both professors of medicine, 

 assumed in a general way that mineral \cins were original cracks in 

 the rocks containing matter that had been changed into vein minerals 

 by some exhalations from the interior. Henkel supposed further that 

 certain kinds of rock or stone which served as matrices were favorable 

 and even absohilcly necessary to the formation of vein minerals. 

 Zimmermann, who, like Ilenkel, was a chemist rather than a miner, 



