SIDEREAL ASTRONOMY. 327 



astronomers have fully confirmed the fact ; and demonstrated 

 the motion of the sun to be about equal to its own semi- 

 diameter, or what is nearly twice the distance of the moon 

 from the earth, every single day. Whither is this vast and 

 unceasing translation in space to lead us ? or what collision 

 or other consequence may it finally involve ? Certain answer 

 there can be none ; though perhaps we may admit the idea 

 of revolution round some centre of gravity (visible or in- 

 visible, single or a system of bodies) as more consistent 

 with the analogies of nature than any other. But against 

 any sudden catastrophe from this movement of our system 

 in space, we are guaranteed by what we know of the distances 

 of the fixed stars. The star we have already taken as an ex- 

 ample, 61 Cygni, though not so near to us as a Centauri, and 

 some others whose parallax has been obtained, is probably 

 much nearer than the majority of those visible to the eye. 

 Yet the Sun, moving at the rate we have just named, would 

 take nearly 400,000 years to accomplish this measured dis- 

 tance! Here then again we gather knowledge and light 

 from amidst this cloud of numbers. We cannot comprehend 

 the whole, but we gain certainty as to a part ; and the general 

 conclusion is made more accessible to all. 



In this chapter on ' Cosmical Space,' Humboldt takes up 

 the enquiry as to the existence of an Ether or material 

 medium, occupying and filling the great domain of the uni- 

 verse ; but makes it rather a record of the opinions of others 

 than any distinct expression of his own. It is in truth, in 

 various ways, one of the most subtle questions which can ex- 

 ercise or perplex the human understanding. On one side it 

 approaches the region of metaphysics ; everywhere it passes 

 beyond the dominion of the senses, and of those exquisite 

 instruments with which human ingenuity has aided them. 

 Modern science thoroughly instructs us that matter and 

 material organisation may exist, and molecular actions take 



