LIFE IN THE PAST 1 55 



volving nebulae had come into comparatively close 

 proximity to a passing body. The visitor, by its at- 

 traction, drew from the nebula a wisp of gas. The 

 revolving motion of the nebula gave to the attracted 

 arm the spiral form. 



These twisted arms are not equally dense through- 

 out, but have thickened knots here and there in their 

 course. The Planetesimal Theory suggests that these 

 thickened knots are embryo planets and the central 

 portion of the nebulae an embryo sun. After all the 

 material in such a body has condensed either around 

 the knots or about the central mass a new solar sys- 

 tem will be complete. As before stated, neither of 

 these theories can be said to be demonstrated. Each 

 of them has points in its favor and each has its diffi- 

 culties. It is pleasant to know what men have clearly 

 thought concerning such questions, but for a man not 

 a trained geologist neither will carry much convic- 

 tion. He will still rest with his own early conclusion 

 that whichever shall prove to be true, for him his 

 old formula is still valid, "in the beginning God made 

 the heavens and the earth." He will no longer think 

 of God as having shaped the balls with his own hand 

 and thrown them into space ; he will no longer dream 

 that it all occurred within a week not more than six 

 thousand years ago; but still to him will come the 

 reverent conviction that, whatever the plan by which 



