THE HEAVENS 369 



does the unaided eye. Photographic plates made in connection with 

 use of the telescope multiply enormously the stars that can be num- 

 bered. There is reason to believe, however, that the number of the 

 stars is not limitless. 



Bode's so-called "law" probably has no value other than as a device 

 for making an easy calculation of the distances of different planets 

 from the sun. It is to be noted that the number to be added to each of 

 the four's is in every case double the preceding number. 



The existence of so many non-luminous companions of the stars has 

 been established that it is not unreasonable to conceive that at least 

 some of the stars are centres of solar systems even as our own sun is. 

 However, astronomers lack sufficient evidence to warrant any such 

 assertion. The human mind naturally wonders if in all the immensity 

 of space, and out of all the multitude of celestial bodies corresponding 

 to what we know as satellites, planets, and sun, our earth alone is in- 

 habited by intelligent beings like ourselves. 



Scientists are very careful to avoid teachings that lack sufficient 

 evidence in known facts to warrant their acceptance. On the other 

 hand, imagination based upon facts, and tested at every stage so far as 

 possible by what is known to be true, enables the human mind to 

 compass the universe. And when the limit of human knowledge is 

 reached, as so quickly it is, the reverent mind readily believes that 

 within the shadows standeth God " Keeping watch above His own." 



