24 HISTORY OF GEOLOGY AND PALEONTOLOGY. 



containing the imbedded fossils rises above sea-level and 

 becomes dry land. 



Agricola, the mineralogist, also made a number of useful 

 observations about springs, earthquakes, active and extinct 

 volcanoes, volcanic rocks, the action of running water, and 

 atmospheric movements. 



Giordano Bruno, who was burnt at Rome in 1600 for heresy, 

 was a natural philosopher of considerable insight. A reprint 

 of his ideas appeared quite recently (Boll. Soc. Natur. Napoli, 

 1895). Bruno described the earth as a spherical body, on 

 whose surface the depths of the oceans were greater than the 

 height of the mountains; the mountains were no higher in 

 proportion to the size of the earth than the wrinkles on the 

 skin of a dried apple. Bruno also denied that there had ever 

 been a universal Deluge, but brought forward evidences of 

 frequent alteration in the distribution of land and sea. He 

 also directed attention to the position of volcanoes in the 

 immediate proximity of the sea, and from that he argued 

 that thermal and volcanic phenomena might be due to some 

 interaction between surface waters and the interior of the 

 earth. Bruno's ideas were not understood by his contempor- 

 aries and were neglected. 



No writer was more appreciated in his time than the 

 accomplished Jesuit, Athanasius Kircher. 1 His famous work, 

 Mundus subterraneiiS) begins with the consideration of the 

 centre of gravity of the earth, and the form and constitution 

 of sun, moon, and earth. Book III. is devoted to hydro- 

 graphy, another book (Pyrologus) treats of the earth's interior, 

 volcanoes, and winds. Kircher's idea is that there are in- 

 numerable subterranean centres of conflagration (pyrophylada}., 

 which are connected with active volcanoes ; similarly that 

 there are special water cavities in the earth (Jiydrophylacia), 

 which are fed from the sea and are connected by branches 



1 Athanasius Kircher was born 2nd May 1602, at Geisa, near Eisenach, 

 and died 1680, in Rome ; was educated in the Jesuit College of Fulda, and 

 took orders in 1618 at Paderborn. He was an accomplished linguist, and 

 travelled through Sicily, Malta, and the Lipari Islands, visiting Etna, 

 Stromboli, and Vesuvius. He was made a Professor in Wurzburg in 1630, 

 but on the approach of the Swedes in 1633, took flight to Avignon, and 

 afterwards accepted the post of teacher of Mathematics in the Collegium 

 Romanum in Rome. There he founded a valuable natural history collec- 

 tion, which was afterwards described by Bonanni in 1709 under the name 

 of Museum Kircherianum, and is still kept up in Rome. 



