10 S. F. EMMONS — THEORIES OF ORE DEPOSITION 



and their greatest service perhaps was in inaugurating geological studies 

 of the great mountain systems of the world, which more than any other 

 branch of geological inquiry have been instrumental in raising this 

 science to its present stand. 



The actual field of observation of Werner, on the other hand, was 

 extremely restricted, scarcely extending beyond the confines of his native 

 Saxony. He had, however, a genius for the analysis^ classification, and 

 coordination of observations, which enabled him to bring order out of 

 the chaos of fact and fancy which then constituted the science. With 

 an eminently didactic mind, he possessed, with much personal charm, 

 such a power of impressing his ideas upon his pupils, that during the 

 forty years that he occupied the chair of mining and mineralogy the 

 Freiberg school was the center of geological studies in Europe. From 

 it emerged so man}' distinguished geologists, as the fruit of his teachings, 

 that, as Cuvier says, " from one end of the world to the other nature was 

 interrogated in the name of Werner." 



Contemporaneously with Werner an equally great service was being 

 rendered to geology at Edinburgh, in Scotland, by James Hutton, who, 

 like so many of the eminent geologists of the world, had been educated as 

 a physician. Hutton, like Werner, taught mainly through his lectures, 

 neither of them finding time for much writing, so that the doctrines of 

 either have become known to posterity mainly through the publications 

 of their pupils. 



Each of these great teachers aimed to discard ^theory and to build 

 their respective systems on a basis of ascertained facts, but in the then 

 existing condition of geological investigation certain fundamental con- 

 ceptions had to be assumed from the interpretation given to as yet im- 

 perfectly studied phenomena. With minds like theirs, strong in the 

 courage of their convictions, an interpretation once fairly reasoned out 

 and accepted became an established fact, and thus it came about that 

 through a difference in their premises their respective systems were dia- 

 metrically opposed, and gave rise to the great controversy between Nept- 

 unists and Plutonists, which, for nearly fifty years, divided the scientific 

 world of Europe into two antagonistic schools. Werner assumed that 

 the earth had once been surrounded by an ocean of water at least as deep 

 as the mountains are high, and that from this ocean there were deposited 

 by chemical precipitation the solid rocks which now form the dry land. 

 He entirely ignored the internal heat of the globe in its influence on crys- 

 talline rocks, on ore deposits, and as a cause of the dislocations of stratified 

 rocks. Hutton, on the other hand, while not ignoring the agency of 

 water in the formation of the sedimentary rocks, ascribed to subterranean 

 heat and the expanding power it exercised their final consolidation, their 



