WILLIAM BARTON ROGERS. 429 



developing the resources of the State. So great was the scientific 

 reputation that Professor Rogers early acquired by such services, that 

 in 1835 he was called to fill the important Professorship of Natural 

 Philosophy and Geology in tlie University of Virginia ; and during 

 the same year he was appointed State Geologist of Virginia, and 

 began those important investigations which will always associate his 

 name with American geology. 



Professor Rogers remained at the head of the Geological Survey of 

 Virginia until it was discontinued, in 1842, and published a series of 

 very valuable annual reports. As was anticipated, the survey led to 

 a large accumulation of material, and to numerous discoveries of great 

 local importance. As this was one of the earliest geological surveys 

 undertaken in the United States, its directors had in great measure to 

 devise the methods and lay out the plans of investigation which have 

 since become general. This is not the place, however, for such de- 

 tails ; but there are four or five general results of Professor Rogers's 

 geological work at this period which have exerted a permanent influ- 

 ence on geological science, and which should therefore be briefly 

 noticed. Some of these results were first published in the American 

 Journal of Science ; others were originally presented to the Associa- 

 tion of American Geologists and Naturalists, and published in its 

 " Transactions." Professor Rogers took a great interest in the organi- 

 zation of this association in 1840, presided over its meeting in 1845, 

 and again, two years later, when it was expanded into the American 

 Association for the Advancement of vScience. 



In connection with his brother Robert, Professor "William B. Rogers 

 was the first to investigate the solvent action of water — especially 

 when charged with carl)onic acid — on various minerals and rocks ; 

 and by showing the extent of this action in nature, and its influence in 

 the formation of mineral deposits of various kinds, he was one of the 

 first to observe and interpret the important class of facts which are the 

 basis of chemical geology. 



Another important result of Professor Rogers's geological work was 

 to show that the condition of any coal-bed stands in a close genetic 

 relation to the amount of disturbance to which the enclosing strata 

 have been submitted, the coal becoming harder and containing less 

 volatile matter as the evidence of disturbance increases. This gen- 

 eralization, which seems to us now almost self-evident, — under- 

 standing, as we do, more of the history of the formation of coal, — 

 was with Professor Ro"ers an induction from a great mass of observed 

 facts. 



