THE UNIVERSE. OCEANIC DISCOVERIES. 261 



currents of the ocean ; the regular decrease of temperature 

 on the declivities of the Cordilleras, and in successive strata 

 of water in descending in the depths of the ocean ; and on 

 the reciprocal operation upon each other of the different vol- 

 canoes forming chains, and their influence on the frequency of 

 earthquakes as well as on the extent of the circles of commotion. 

 The groundwork of what we now term physical geography, 

 (abstracting from it mathematical considerations,) is found 

 in the Jesuit Joseph Acosta's " Historia natural y moral de 

 las Indias," as well as in the work by Gonzalo Hernandez de 

 Oviedo, which appeared only twenty years after the death 

 of Columbus. Never, since the commencement of civil 

 society, was there an epoch in which the sphere of ideas as 

 regards the external world and geographical relations was so 

 suddenly and wonderfully enlarged, or in which the desire 

 of observing nature under different latitudes and at different 

 elevations above the level of the sea, and of multiplying the 

 means by which her secrets might be interrogated, was more 

 keenly felt. 



It has, perhaps, as I have elsewhere remarked, ( 407 ) been 

 erroneously supposed, that the value of these great discoveries, 

 each of which in turn promoted others, of these twofold 

 conquests in the physical and in the intellectual world, was 

 not felt until its recognition in our own days, when the 

 history of the intellectual cultivation of mankind is made a 

 subject of philosophic study. Such a supposition is 

 refuted by the writings of the cotemporaries of Columbus. 

 The feelings of the most talented among them anticipated 

 the influence which the events of the latter part of the fif- 

 teenth century would exert on mankind. Peter Martyr de 

 Anghiera ( 408 ) says, in his letters written in 1493 and 1494, 



