280 ETHER AND GRAVITATIONAL MATTER. 



Sec. 22. There may also be a large amount of matter in many stars 

 outside the sphere of 3.10 16 kilometers radius, but however much mat- 

 ter there may be outside it. it seems to be made highly probable by 

 sections 11—21 that the total quantity of matter within it is greater 

 than 100,000,000 times and less than 2,000,000,000 times the sun's 

 mass. 



I wish, in conclusion, to express my thanks to Sir Norman Lockyer, 

 to the Astronomer Royal. Mr. Christie, to Sir Robert Ball, and to Pro- 

 fessor Becker for their kindness in taking much trouble to give me 

 information in respect to astronomical data, which has proved most 

 useful to me in sections 11-21, above. 



