THE LESSON OF EVOLUTION 1 1 



From this theory of " dissipation of energy " it 

 follows that, as the earth is cooling, life cannot go on 

 for ever ; and also that at some former time the Earth 

 must have been too hot for the existence of protoplasm. 

 Consequently life can only have a limited existence on 

 the earth. It must have had a beginning and it must 

 come to an end. 



But the inference extended further. Not only 

 living beings but even the whole Solar System must 

 have had a beginning, not infinitely remote ; because 

 most of its members still contain a large amount of 

 their original heat. And if the Solar System had a 

 beginning, so also must each star in the heavens have 

 had a beginning ; for the very fact that we can see 

 them is a proof that they are radiating out energy. 

 And, it was asked, why should not the whole Universe, 

 visible and invisible, have had a common origin and a 

 common beginning in time ? This had been the 

 opinion of Immanuel Kant in the middle of the 

 eighteenth century ; and, although modern astronomy 

 has not altogether confirmed his speculations, it has 

 proposed an hypothesis which is not very dissimilar. 

 This is the " Meteoritic Hypothesis," and is chiefly 

 the work of Sir Norman Lockyer and Professor G. H. 

 Darwin. I will give you a short sketch of the views 

 held by the former. 1 



INORGANIC EVOLUTION. 



The close connection between the orbits of comets 

 and those of meteoritic streams has led to the uni- 



1 See the "Meteoritic Hypothesis," Macmillan, 1890; and 

 " Inorganic Evolution," Macmillan, 1900. 



