i 7 4 POPULAR SCIENCE MONTHLY. 



it in the highest degree interesting wherever it may be found — sen- 

 tient life. 



It does not follow, however, that there are no real planetary 

 bodies revolving around the stars. As Dr. See himself remarks, such 

 insignificant bodies as our planets could not be seen at the distance 

 of the fixed stars, " even if the power of our telescopes were increased 

 a hundredfold, and consequently no such systems are 'known." 



This brings me to another branch of the subject. In the same 

 article from which I have already quoted (Recent Discoveries re- 

 specting the Origin of the Universe, Atlantic Monthly, vol. lxxx, 

 pages 484-492), Dr. See sets forth the main results of his well-known 

 studies on the origin of the double and multiple star systems. He 

 finds that the stellar systems differ from the solar system markedly 

 in two respects, which he thus describes: 



'' 1. The orbits are highly eccentric; on the average, twelve 

 times more elongated than those of the planets and satellites. 



" 2. The components of the stellar systems are frequently equal 

 and always comparable in mass, whereas our satellites are insignifi- 

 cant compared to their planets, and the planets are equally small 

 compared to the sun." 



These peculiarities of the star systems Dr. See ascribes to the 

 effect of " tidal friction," the double stars having had their birth 

 through fission of original fluid masses (just as the moon, according- 

 to George Darwin's theory, was born from the earth), and the reac- 

 tion of tidal friction having not only driven them gradually farther 

 apart but rendered their orbits more and more eccentric. This man- 

 ner of evolution of a stellar system Dr. See contrasts with Laplace's 

 hypothesis of the origin of the planetary system through the suc- 

 cessive separation of rings from the periphery of the contracting- 

 solar nebula, and the gradual breaking up of those rings and their 

 aggregation into spherical masses or planets. While not denying 

 that the process imagined by Laplace may have taken place in our 

 system, he discovers no evidence of its occurrence among the double 

 stars, and this leads him to the following statement, in which 

 believers in the old theological doctrine that the earth is the sole 

 center of mortal life and of divine care would have found much 

 comfort : 



" It is very singular that no visible system yet discerned has any 

 resemblance to the orderly and beautiful system in which we live; 

 and one is thus led to think that probably our system is unique in 

 its character. At least it is unique among all known systems." 



If we grant that the solar system is the only one in which small 

 planets exist, revolving around their sun in nearly circular orbits, 

 then indeed we should seem to have closed all the outer universe 



