148 PLEASANT WAYS IN SCIENCE. 



our sun in long past ages a more satisfactory explanation 

 than any yet obtained may be found of the problem 

 geologists find so perplexing the former existence of a 

 tropical climate in places within the temperate zone, or even 

 near the Arctic regions.* 



It remains that I should exhibit the general results to 

 which I have been led. It has seemed to many that my 

 views tend largely to diminish our estimate of the extent 

 of the sidereal system. The exact reverse is the case. 

 According to accepted views there lie within the range of 

 our most powerful telescopes millions of millions of suns. 

 According to mine the primary suns within the range of our 

 telescopes must be counted by tens of thousands, or by 

 hundreds of thousands at the outside. 'What does this 

 diminution of numbers imply but that the space separating 

 sun from sun is enormously greater than accepted theories 

 would permit? And this increase implies an enormous 

 increase in the estimate we are to form of the vital energies 

 of individual suns. For the vitality of a sun, if one may 

 be permitted the expression, is measured not merely by the 

 amount of matter over which it exercises control, but by 

 the extent of space within which that matter is distributed. 

 Take an orb a thousand times vaster than our sun, and 

 spread over its surface an amount of matter exceeding a 

 thousandfold the combined mass of all the planets of the 

 solar system : So far as living force is concerned, the result 

 is nil. But distribute that matter throughout a vast space 

 all round the orb : That orb becomes at once fit to be the 

 centre of a host of dependent worlds. Again, according 

 to accepted theories, when the astronomer has succeeded 

 in resolving the milky light of a portion of the galaxy into 

 stars, he has in that direction, at any rate, reached the limits 

 of the sidereal system. According to my views, what he 



* Sir John Herschel long since pointed to the variation of our sun as 

 a possible cause of such changes of terrestrial climate. 



