CHAPTER XXXII 



THE COSMIC EXCHANGE OF MATTER 

 AND LIFE 



WHEN, after so many centuries of prediction and expectation, 

 the New World was actually found, Europe could not rest for 

 thinking ks full of wonders, as men had dreamed so long. The 

 persistence of this belief seems curious now. Nowadays the 

 trained imagination of the scientific adventurer has no such 

 expectations of the unknown. There may be some;witless folk 

 left still to believe that if we could reach the North Pole we 

 should find griffins and goblins and giants and genii. What the 

 four hundred intervening years since Columbus have taught us 

 mainly is the art of accurate inference and prediction. We can 

 foretell what the polar regions are like, and we know them to 

 be destitute of any sane man's interest. Can we form any idea 

 of worlds outside our own ? 



If it should turn out that the stellar universe has no more 

 real " structure " than that of a gas if the resemblance to the 

 kinetic theory of gases which I have suggested should be veri- 

 fied, the fact would carry with it many interesting implications. 

 One of these would be the incessant exchange incessant at 

 least in the sense of cosmic time of the material and of the 

 units of which this universe is composed, perhaps of life as 

 well. This could but mean the ultimate identity of the world 

 scheme throughout the farthest reaches of space. 



If we follow the analogy of the kinetic theory, we must 

 either conceive of the number of dark suns or dark bodies as 

 very great, or else picture the universe as a gas which is very 

 thin. The molecules of the air which we breathe, for example, 

 are not spaced at anything like the distances which we at pre- 

 sent regard as the average spacing of the suns. When the air 

 is reduced to a liquid or frozen solid, or what is very nearly 

 the same thing, when water goes over into vapour or steam, 



the difference of the volume occupied is not enormous. A cubic 



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