at the spot where it originated, and passes from the consider- 

 ation of the known to the unknown, of the near to the distant 

 It corresponds with the method pursued in our elementary 

 works on astronomy (and which is so admirable in a mathe- 

 matical point of view), of proceeding from the apparent to the 

 real movements of the heavenly bodies. 



Another course of ideas must, however, be pursued in a 

 work which proposes merely to give an exposition of what is 

 known — of what may in the present state of our knowledge 

 be regarded as certain, or as merely probable in a greater or 

 lesser deofree — and does not enter into a consideration of the 

 proofs on which such results have been based. Here, there- 

 fore, we do not proceed from the subjective point of view of 

 human interests. The terrestrial must be treated only as a 

 part, subject to the whole. The view of nature ought to be 

 grand and free, uninfluenced by motives of proximity, social 

 sympathy, or relative utility. A physical cosmography — a 

 picture of the universe — does not begin, therefore, with the 

 terrestrial, but with that which fills the regions of space. But 

 as the sphere of contemplation contracts in dimension our per- 

 ception of the richness of individual parts, the fullness of phys- 

 ical phenomena, and of the heterogeneous properties of mat- 

 ter becomes enlarged. From the regions in which we rec- 

 ognize only the dominion of the laws of attraction, Ave de- 

 scend to our own planet, and to the intricate play of terrestrial 

 forces. The method here described for the delineation of na- 

 ture is opposed to that which must be pursued in establish- 

 ino- conclusive results. The one enumerates what the other 

 demonstrates. 



Man learns to know the external world through the organs 

 of the senses. Phenomena of light proclaim the existence of 

 matter in remotest space, and the eye is thus made the me- 

 dium through which we may contemplate the universe. The 

 discovery of telescopic vision more than two centuries ago, has 

 transmitted to latest generations a power whose limits are as 

 yet unattained. 



The first and most general consideration in the Cosmos is 

 that of the contents of space — the distribution of matter, or 

 of creation, as we are wont to designate the assemblage of all 

 that is and ever will be developed. We see matter either 

 agglomerated into rotating, revolving spheres of different dens- 

 ity and size, or scattered through space in the form of self- 

 luminous vapor. If we consider first the cosmical vapor dis 

 persed in definite nebulous spots, its state of aggregation will 



