470 COSMOS. 



speedily established. We have already shown how a period of 

 fluctuations between truth and error is especially one of presen- 

 timents and fanciful hypotheses regarding natural philosophy. 

 After treating of the extended knowledge of nature as a 

 simultaneous consequence of direct observations and ideal 

 combinations, we have proceeded to the consideration of those 

 historical events which have materially extended the horizon 

 of the physical contemplation of the universe. To these 

 belong migrations of races, voyages of discovery, and mili- 

 tary expeditions. Events of this nature have been the means 

 of our acquiring a knowledge of the natural character of 

 the Earth's surface, (as, for instance, the configuration of 

 continents, the direction of mountain chains, and the relative 

 height of elevated plateaux), and in the case of extended 

 tracts of land, of presenting us with materials for expound- 

 ing the general laws of nature. It is unnecessary, in thia 

 historical sketch, to give a connected tissue of events, and it 

 will be sufficient, in the history of the recognition of nature 

 as a whole, to refer merely to those events which, at early 

 periods, have exercised a decided influence on the mental 

 efforts of mankind, and on a more extended view of the 

 universe. Considered in this light, the navigation of Colseus 

 of Samos, beyond the pillars of Hercules ; the expedition of 

 Alexander to Western India; the dominion exercised by the 

 Romans over the then discovered portions of the world ; the 

 extension of Arabian cultivation, and the discovery of the New 

 Continent, must all be regarded as events of the greatest 

 importance for the nations settled round the basin of the 

 Mediterranean. My object is not so much to dwell on the 

 relation of events that may have occurred, as to refer to the 

 action exercised on the development of the idea of the Cosmos 

 by events, whether it be a voyage of discovery, the establish- 

 ment of the predominance of some highly developed language 

 rich in literary productions, or the sudden extension of the 

 knowledge of the Indo- African monsoons. 



As I have already incidentally mentioned the influence of 

 language in my enumeration of heterogeneous inducements, I 

 will draw attention generally to its immeasurable importance 

 in two wholly different directions. Languages, when exten- 

 sively diffused, act individually as means of communication 

 between widely separated nations, and collectively when several 



