xii TOWARDS INFINITY 315 



that beyond the phenomena which have so far been 

 brought within the range of our senses there may be 

 many others awaiting to be revealed by more potent 

 or refined means of observation, or new methods of 

 inquiry. During the past few years, for example, the 

 conviction has been forced upon astronomers that there 

 are probably more dark stars than bright ; and that 

 completely blank regions here and there in the sky 

 represent immense clouds of non-luminous cosmic dust 

 which blot out the light of stars behind them. 



Masses of material have been revealed by photography 

 which are beyond the visual reach of the largest tele- 

 scopes ; many bright stars have been found to possess 

 acolytes ponderous enough to influence their movements 

 but without intrinsic luminosity ; and the millions of 

 meteoritic particles which enter the earth's atmosphere 

 daily, producing the appearance of shooting stars or 

 meteors, show that space should not be regarded as a 

 void, but rather as a plenum of dead matter. 



It is easy to understand that as the power of seeing is 

 enlarged by the improvement of instruments or the 

 development of methods of inquiry, new spheres are 

 brought within the range of human knowledge. Our 

 eyes have in truth been opened by the lenses of giant 

 telescopes, and we have come to know that greatness 

 is not to be measured by visibility. For not only are the 

 stars revealed by telescopes vastly more numerous than 

 those bright enough to be seen by the naked eye, but 

 they also contribute more to the total quantity of star- 

 light received by the earth than the brilliant objects 

 which make a view of the midnight sky an impressive 

 sight. As it is estimated that three-quarters of the total 

 starlight that reaches this world of ours is from stars 

 beyond the grasp of unaided vision, it is not difficult to 



