322 THEORIES OF ORE DISPOSITION HISTORICALLY CONSIDERED. 



canic regions. The cosmic theory, generally knoAvn as the " nebular 

 hypothesis," the one which has been most universally accepted by 

 geologists as an explanation of the earth's beginnings, as finally re- 

 ceived, was the work of a French mathematician, Laplace (1796). 

 Hence, in seeking to account for the origin of ore deposits they were 

 naturally inclined to look for igneous agencies. Thus, A. Burat, 

 well known through his work' " Applied Geology," 1843, took extreme 

 Plutonic views and divided the copper, lead, and iron deposits of the 

 Italian peninsula, which he had esj^ecially studied, into (1) dikes or 

 eruptive masses, with gangue of amphibolite and livaite; and (2) 

 irregular veins of contact between eruptive serpentine and sedi- 

 mentary rocks. The Elba deposits of specular iron, which he re- 

 garded as striking instances of the first class, he considered to have 

 exercised an elevatory as Avell as metamorphic action on the inclosing 

 rocks at the time of their injection. Fournet, another j^rominent 

 authority on the subject, maintained a theory of igneous injection for 

 vein fillings as late as 1859. 



As in Germany, it was the professors in the mining schools, espe- 

 cially those at Freiberg, who, in the early part of the century, led in 

 forming scientific opinion as to ore deposition, so it was the School 

 of Mines at Paris which later furnished the leaders in that branch of 

 geological thought. 



The French students of underground phenomena were at a certain 

 disadvantage as compared with their German brethren, in that they 

 were obliged to travel to foreign countries to study large mines, 

 whereas the German schools were all situated in the midst of impor- 

 tant mining districts. On the other hand, while the German displays 

 great industry and acuteness of observation in his collection of facts, 

 the Frenchman has a remarkable faculty of logically grouping them 

 and of clearly and concisely stating the conclusions to be drawn 

 therefrom. The French language, moreover, by its structure is much 

 better adapted to a concise presentation of scientific concepts that may 

 be readily understood by the reader than the German, which is likely 

 to be involved and cumbersome in its mode of expression. Hence, 

 toward the middle of the century the influence of the French geolo- 

 gists on genetic speculation became predominant, especially as it 

 was based on synthetic experiment, a branch of geological investiga- 

 tion which for a time they practically monopolized. 



The first of the French geologists who has left an enduring impress 

 upon the theory of ore deposits was Elie de Beaumont, who for nearly 

 fifty years occupied the chair of geology at the Paris School of Mines 

 (1827-1874). In 1847 he published, as an abstract of his lectures, his 

 well-known paper '^ Volcanic and metalliferous emanations," in which 

 he does not claim to formulate a complete or final theory, but presents 

 his views as explanations which seemed to him best to fit the facts of 



