INTRODUCTION. 57 



ena which are found to be distributed in various g^roups, I would 

 consider a few general questions intimately connected together, 

 and bearing upon the nature of our kno^vledge of the external 

 world and its different relations, in all epochs of history and in 

 all phases of intellectual advancement. Under this head will 

 be comprised the following considerations : 



1 . The precise limits of the physical description of the uni- 

 verse, considered as a distinct science. 



2. A brief enumeration of the totality of natural phenomena, 

 presented under the form of a general delineatioii of nature. 



3. The influence of the external world on the imagination 

 and feelings, which has acted in modern times as a powerful 

 impulse toward the study of natural science, by giving anima- 

 tion to the description of distant regions and to the delineation 

 of natural scenery, as far as it is characterized by vegetable 

 physiognomy and by the cultivation of exotic plants, and their 

 arrangement in well- contrasted groups. 



4. The history of the contemplation of nature, or the pro- 

 gressive development of the idea of the Cosmos, considered 

 with reference to the historical and geographical facts that 

 have led to the discovery of the connection of phenomena. 



The higher the point of view from which natural phenome- 

 na may be considered, the more necessary it is to circumscribe 

 the science within its just limits, and to distinguish it from all 

 other analogous or auxiliary studies. 



Physical cosmography is founded on the contemplation of all 

 created things-:-all that exists in space, whether as substances 

 or forces — that is, all the material beings that constitute the 

 universe. The science which I would attempt to define pre- 

 sents itself, therefore, to man, as the inhabitant of the earth, 

 under a two-fold form — as the earth itself and the reo-ions of 

 space. It is with a view of showing the actual character and 

 the independence of the study of physical cosmography, and at 

 the saraie time indicating the nature of its relations to general 

 fhysics, descrij)tive natural history, geology, and comparative 

 geography, that I will pause for a few moments to consider 

 that portion of the science of the Cosmos which concerns the 

 earth. As the history of philosophy does not consist of a mere 

 material enumeration of the philosophical views entertained 

 in different ages, neither should the physical description of the 

 universe be a simple encyclopedic compilation of the sciences 

 we have enumerated. The difficulty of defining the limits of 

 intimately-connected studies has been increased, because for 

 centuries it has been customary to designate various branches 



C2 



