68 LIGHT SCIENCE FOR LEISURE HOURS. 



scheme of motions, whose laws are as yet unknown to 

 us. We may recognise in the method of research which 

 has now been so successfully applied, the sole means of 

 determining what those laws may be. We can now tell 

 the very rate, in miles per annum, at which the suns 

 are approaching or receding from us ; and though we 

 have no reason for believing that our sun occupies in 

 any sense a central position so that we have yet to 

 learn at what rate and in what way the stars move 

 around the true centre of their system, yet it is far 

 from unlikely that if we can but ascertain the motions 

 of a sufficient number of stars, we shall have the 

 means of judging where the centre lies round which 

 these motions are taking place. 



The astronomer may well look with doubt, however, 

 on the efforts which are being made to solve this stu- 

 pendous problem. If we may judge from the analogy 

 of our own solar system, we can see that in the far 

 more complicated scheme of the stars there must exist 

 innumerable features to perplex the observer. If we 

 imagine a being placed in the midst of the solar system, 

 and enabled to study the various apparent motions 

 visible from his stand-point, and if we further suppose 

 him gifted with the power of measuring the rate at 

 which the various orbs are approaching him or receding 

 from him, then we know that if his scrutiny were but 

 continued long enough, he could not fail to recognise 

 the laws which exist within that system and regulate 

 all those motions. Where at first all had seemed con- 

 fusion, our imaginary observer would recognise in the 





