GROWTH OF EXPERIMENTAL SCIENCE 175 



which the many unforeseen difficulties, which always present themselves 

 in such an investigation, were surmounted and the infinite patience with 

 which the investigation was followed out mark Hall as an investigator 

 of high rank. He carried out some 500 experiments, and a whole battery 

 of gun-barrels burst in the course of the investigation ; but he succeeded 

 eventually in converting the powdered chalk by heat and pressure into 

 a material which was to all intents and purposes a fine-grained marble, 

 thus proving that the presence of this rock in a complex of crystalline 

 schists could not be taken as evidence that these rocks were aqueous pre- 

 cipitates, but that, on the contrary, it conveyed the suggestion that they 

 had during their formation been submitted to conditions of great heat 

 and pressure. 



The arguments of the Neptunists were thus finally overthrown by 

 Hall's investigations, and he well merits the honor which is bestowed on 

 him when he is called "the Father of Experimental Geology." 



The recognition of the fact that much valuable information, contribut- 

 ing in no small measure to the understanding of many recondite processes 

 which are at work in nature, might be obtained through experiments, 

 where the conditions which obtain in the earth's crust are reproduced as 

 closely as possible in the laboratory, now commenced to draw the atten- 

 tion of an ever increasing number of geologists to the importance of ex- 

 perimental work. Among these may be mentioned Sorby, Pfaff, Kick, 

 Michel Levy, Fouque, Cadell, Doelter, Spring, Meunier, Bailey Willis, 

 and especially Daubree, who for over forty years devoted himself untir- 

 ingly to the pursuit of experimental geology and whose great work, en- 

 titled "Etudes synthetiques de Geologic Experimentale," published in 

 1879, will ever remain one of the classics in this subject. 



One of the lines along which such experimental study has yielded im- 

 portant results to geological science may be referred to briefly, namely, 

 the experimental study of the development of mountain ranges. 



The Alps, situated as they are in the very heart of Europe, have been 

 subjected to more continuous and intensive study than any other moun- 

 tain range in the world. The serious attempts to unravel their structure 

 may be said to have extended over the lifetime of three successive Swiss 

 geologists — De Saussure, Arnold Escher von der Linth, and his pupil, 

 Albert Heim, representing the period from 1740 to the present time. 



In the earlier part of this period the mountain range was considered 

 to be a jumbled assemblage of rock-masses without definite or recogniz- 

 able structure of any kind — a mere chaos of broken pieces of the earth's 

 crust. Gradually it came to be seen that in addition to more or less 

 massive rocks of obscure orio^in there were stratified elements in the vari- 



