STELLAR EVOLUTION. Hu) 



We must look to tlio >u^)lar system for exampk's of stars in the last 

 stage of development. Each of t\w planets may, in fact, he regarded 

 as an object of this kind. Jhc bare and rocky surface of the moon 

 affords a desolate pictui-e of what may result from this long-continued 

 process of condensation. The volcanic region, which is shown to 

 excellent advantage in a photograph recently taken with the Yerkes 

 telescope (Fl. XI), gives no evidence of the existence of life; in fact, 

 the spectroscope indicates that if there is any air on the moon it is 

 much too rare to support life as we know it. 



Fortunately, the moon is not the only example of a worn-out star. 

 The earth, which probably has many counterparts in the universe, is 

 another example of a less desolate kind. Here, though the process 

 of condensation which is the chief cause of celestial phenomena has 

 ceased, the problem of evolution has not ended. In fact, though the 

 cosmical problems which we have considered in their barest elements 

 will not be completely solved for centuries, it may be truly said that 

 the questions raised by the countless living organisms in a single drop 

 of ditch water are still more complex and will require a still longer 

 time for their solution. 



