314 THEORIES OF ORE DISPOSITION HISTORICALLY CONSIDERED. 



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

 a cause of misconception among modern readers Avho have occasion 

 to consult the older works on geology and mineralogy. 



For over a century after Agricola there aj^pears to have been little 

 w^ritten that had any special bearing 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 probabh' have been 

 prompted by the theories of the cosmic philosophers, so that by the 

 close of the eighteenth centur}^ there had accumulated considerable 

 speculative literature on this subject. 



The following is a list of the more frequently quoted Avorks tliat 

 appeared during this 2:)eriod, with the approximate dates of their 

 j)ublication : 



Speculuin Motallurjii.c politissiiimiii. by P.ergmeistor Bnlthusar lii'lsler (1700). 



Physiea subton-auea, by J. J. Beeher. Coniineiitated by G. S. Stahl. Second 

 edition (1703). 



Pyritologia, by .7. F. Ilenkol, j)rofessor of cliemistry and mineralogy, Freiberg 

 (1725). 



Obersiichsicbe Bergakadeniie, l)y C. F. Zininierniaun, councilor of mines 

 (1749). 



Markscheidekunst, by Von Oppel. vice-director of Saxon mines (1740). 



Abh. V. d. Metalmuttcu'u, etc., by D. J. 11. Lebman, director of Prussian mines 

 (1753). 



Elementa Metallurgia' Cbemicne, by W. J. Wallerius. Stockholm (17t!8). 



Ursprung d. (iebirge u. Erzaderu, etc., by C. F. Delius, professor of metal- 

 lurgy at Scbemnitz (1770). 



Mineral, (ieograpb. d. Kursiicbsiscbe Lander, by J. F. W. de ("barpentier, 

 director of Sa.xon mines ( 177S). 



Unterirdisebe Geograpbic, by I. (J. Baumer, Giessen (1770). 



Gesch. d. Metallreicbs, Ijy G. A. Gerhard, councilor of mines (1781). 



Erfahr. ii. d. Innern d. Gebirge. by F. M. H. v. Trebra, vice-director of Han- 

 overian mines (17.S."i). 



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

 survey of Hanover (17S7). 



The views of most of these early writers were rather cui'ious than 

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

 hirgest practical experience in mines, are remarkably suggestive. 



Rosier, the earliest recorded mine superintendent, recognized that 

 veins difl'er from ordinary cracks in the rocks only by being filled 

 W'ith metallic minerals, but did not speculate on their genesis. 

 Beeher and his counnentator, Stahl, both professors of medicine, 

 assumed in a geueral wa}' that uiiiieral veins were original cracks in 

 the rocks containing matter that had been changed into vein minerals 

 by some exhalations from the intei-ior. Henkel supposed further that 

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

 and even absolutely necessarj^ to the formation of vein minerals. 

 Zimmermann, Avho, like Henkel, was a chemist rather than a miner. 



