54 



There have been many attempts i<> formulate a theory of evolution for 



the earth, the solar system, and indeed the whole sidenal universe. Un- 

 fortunately, mos1 of these were based on comparatively little scientific data 

 and any actual proofs of reliability or truth were lacking. Mosl of them 

 might better be called speculations, pure and simple, and were produced 

 largely from analogy. For example, we have known for some three hundred 

 years that the planets circulate about the sun in nearly the same plane, the 

 ones near the sun moving faster than those farther away. The visible 

 universe is apparently arranged more or less in one plane or at least is very 

 much extended in the plane of the Milky Way. the solid figure that would 

 enclose the solar system not being greatly different, except in size, from the 

 one which would enclose all the stars. What would be more matural then 

 than to suppose that the Avhole universe was built up on a large scale much 

 as the planetary system, the sun being in revolution with many others 

 about some distant center. These, in turn, perhaps, revolving about 

 another center till the whole Universe is accounted for. Some such idea 

 was advanced by Kant who had only the Law of Gravitation upon which 

 to base his speculations. Unfortunately he knew nothing of the distances of 

 the stars. At that time no one knew from actual observation that the 

 stars had any real motions of their own through space. 



We know little enough of these things now, but a few facts have been 

 established with certainty in the last hundred years, indeed most of our 

 accurate knowledge of the stars being attained in much more modern times. 

 It was not till 1839 that we knew the distance of a single star in the whole 

 sky, and only in the last fifty years has it been possible to measure their 

 motions in any very precise way. 



Following the above general theory it was supposed for a while that the 

 central point about which the whole siderial system revolved had been lo- 

 cated in Alcyone, the brightest of the Pleiades. It is sufficient to say that 

 there is not a particle of evidence to sustain this conclusion, or the conclusion 

 that the stars, as a whole, revolve about any center whatever. As far as 

 we know the stars move in all sorts of directions and with all sorts of veloci- 

 ties. We are lacking now as much as a thousand years ago any theory of the 

 evolution of the system of the stars, which is based upon observed changes 

 in the stars themselves. The theories and speculations regarding the origin 

 and history of the planetary system are more numerous and in some cases as 

 improbable and impossible as those regarding the universe. The best 



