The Structure of the Atlantic : 35 



picture of the five-foot globe in order to acquire a certain perspective 

 regarding the proportions of our earth. To emphasize these propor- 

 tions, we have talked in terms of a steel ball. That was all right for 

 our purpose, but now we shall have to make certain corrections. 

 Though the interior of our earth is actually very dense and under 

 great compression, the surface of the continents are made of rock and 

 dirt and sand which contrast, of course, with the ocean water. Photo- 

 graphs have now been taken of the earth from a V2 rocket in flight 

 and they begin to show how the earth actually looks as we move out 

 into space. It does look like a very solid smooth ball. The curvature 

 of the earth begins to be apparent but the outlines of the oceans and 

 seas and lands are apparent too. Clouds appear as a very low-lying 

 fuzzy scum, drifting here and there over the sea. An observer on the 

 moon with a good pair of field glasses could, after a period of time, 

 create a very good picture of the structure of our earth. He could do 

 so, not because of the difference in height of the structure of the earth, 

 but because land and water receive and reflect light in quite different 

 ways. Now one of the most significant things that an astronomer on 

 the moon or some planet would notice and record about our planet 

 is that it did have an atmosphere and that it was wet. If he had about 

 the same scientific equipment that our astronomers have, the astron- 

 omer on Mars would conclude that the earth is very unusual and 

 interesting because it could sustain life — including human life. Even 

 from the astronomer's point of view, these thin oceans are therefore 

 of the greatest importance. 



This five-foot globe representing the earth can leave with us not 

 only a vivid picture of the mountains, the seas and the atmosphere, 

 but also a just and useful sense of their true proportions. It relates us 

 to reality, it shows us how vast in area and how thin in depth is the 

 stage setting in which man has been performing the human drama. 

 This vision of the earth is not exaggerated; though it seems hard to 

 believe, it is in fact an understatement. 



Though the shell of the earth from mountain height to abyss is 

 but a thin eggshell in space, man's hold on life hangs on a still thin- 

 ner film. It is not all levels of the earth or depths of the sea that are 

 useful to living creatures. Photosynthesis, the process by which sun- 

 light builds up in plants the ingredients that are required for the proc- 

 ess of living by all creatures, and other chemical and bacteriological 

 actions that are essential to life are confined to a film that, on our 

 globe, would be so incredibly thin as to be ultra-microscopic. In the 

 case of the oceans there is some depth to the zones on which life is 



