THE SCIENTIFIC PERIOD 9 



anxious to present a theory, he says he can not see from his observation 

 of the workings of nature any other method for the formation of veins or 

 other ore deposits than by an actual transformation of the rock material. 

 Nature's processes have created innumerable small cracks and fissures 

 in the rocks, and when a great number of such cracks lie together and 

 in a common direction they might give rise to a considerable vein deposit. 

 Vapors bringing iu mineral solutions might penetrate these small cracks, 

 as the sap rises in capillary tubes in organic bodies. If thereby the in- 

 termediate rock mass became changed into vein material, a vein deposit 

 might be created without the necessity of wide empty spaces for its 

 reception. 



Rather more than usual space has been given here to Charpentier's 

 work because of the striking contrast of his mental attitude with that 

 of his great successor, Werner, whose reputation so completely over- 

 shadowed him that he has received less notice from later writers than 

 seems to be his due. 



THE SCIENTIFIC PERIOD 



The first scientific period may be said to have been entered on near 

 the close of the eighteenth century, when De Saussure (1779), Pallas 

 (1777), and Werner (1791) almost simultaneously inaugurated by their 

 works the era of positive geology. It was about the same time that 

 chemistry was placed on a scientific basis by the researches of Lavoisier, 

 Scheele, Priestly, Cavendish, and others. Up to this time even the name 

 geology had hardly been recognized, natural history or mineralogy being 

 the titles usually given to works that treated of it, and the few exact facts 

 with regard to it which such men as Agricola, Steno, and others -had 

 determined were drowned in a sea of conjectures. On the Continent it 

 was the mining schools that principally fostered mineralogic and geog- 

 nostic studies, and these had been but recently founded, that at Freiberg, 

 Saxony, in 1765 ; at Schemnitz, Hungary, in 1770 ; at Saint Petersburg 

 in 1783, and at Paris in 1790. Geological literature, especially in Ger- 

 many, went hand in hand with that on mining and mineralogy. 



Of the three men just named, the two first were eminently observers. 

 Pallas, after being called to the mining school at Saint Petersburg, had 

 made a six years 1 geological expedition through the mountains of Russia 

 and Siberia, and De Saussure for over thirty years was largely busied 

 in studying geological phenomena in his native Alps, being the first to 

 climb Mont Blanc and Monte Rosa. He also appears to have been the 

 first to use the name geology for his science. While neither of these 

 men contributed much to the advancement of geological theory, they 

 added largely to the store of ascertained fact, which is its necessary basis, 



II— Bum,. Geol. Soc. Am., Vol. 15, 1903 



