CHAPTER I. 

 THE NATURE OF THE PROBLEM 



SOME time in the remote past, in the remote corner of space 

 that our solar system then occupied, a huge fragment was 

 torn from the glowing central mass and began to press and 

 squeeze into the form of our planet. How it was detached 

 from the contracting fiery cloud, whether as a ring at the 

 surface or a projected mass, we cannot say with confidence. 

 When it was detached is equally a matter of conjecture. 

 We can only say that the limitations which Lord Kelvin so 

 long imposed on geological estimates have been discredited 

 by the discovery of radio-activity, and the vista of the past 

 stretches out endlessly before the calculating mind. The 

 present President of the British Association invites us to think 

 of it in terms of 1,000 or even 2,000 million years. Those 

 are problems of the future. It is germane to my inquiry 

 merely to state that at some inconceivably remote epoch 

 our planet was a fiery offspring of the sun, a formless 

 chaotic mass, millions of miles in diameter. When we 

 remember that the sun is now 150 times as luminous as the 

 incandescent lime in the optic lantern, and has a tempera- 

 ture expressed in several thousands of degrees, we realise 

 that the little sun our earth then was had no living things 

 upon or within it. 



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