The Structure of the Atlantic : 33 



inaccurate, but for our purpose this does not matter, because the 

 thing we are after is a matter of comparative and not absolute size. 

 Let us assume the earth has a radius of 4,000 miles, diameter of 8,000 

 miles and a circumference of 25,000 miles. Of course, scientists will 

 point out that the earth is not a sphere but to a certain degree an 

 "oblate spheroid of rotation." We come to this point in a moment. 



Now let us reduce this earth to a size we can easily look at. The eye 

 height of the average human being is not too far from five feet five 

 inches, so let us take a block of steel of sufficient diameter and turn it 

 down as smoothly as we can into a sphere that has a five-foot diame- 

 ter and is perfectly smooth everywhere. Now this sphere will represent 

 the earth and on it, keeping to scale, we will show the continents and 

 the oceans. How much metal do you think we should cut away to 

 represent the deepest sea? How much metal do you think we should 

 have to build up to represent the highest mountain? The answer is 

 rather surprising. The highest mountains in the United States would 

 be represented by a little roughness 1/50 of an inch in height. The 

 highest mountain in the world. Mount Everest, a little over 29,000 

 feet, would be represented by an elevation of 1/25 of an inch. The 

 deepest depth ever measured in any ocean is a little deeper than 

 Mount Everest is high. It occurs, not in the Atlantic, but in the Pa- 

 cific. The Philippine Deep runs to about 33,000 feet. So this would be 

 represented by a little scratch in our globe about 1/25 of an inch in 

 depth. 



To get a clear image of these relationships, let us imagine that we 

 are representing on our globe the sum total of the height of Mount 

 Everest and the depth of the deepest part of the Philippine Deep as 

 lying right beside each other. We could represent this by a flat piece 

 of cardboard stuck on our globe. Standing some ten feet away from 

 our five-foot globe, we could see that the cardboard was there. Of 

 course, actually the highest mountains and deepest seas are separated 

 by thousands of miles. If our globe represented these in proper scale, 

 we would possibly notice a slight irregularity in outline here and 

 there. If the light were coming from the right direction and we saw 

 the roughness, we might infer that the mechanic who turned our 

 metal globe had had a slightly unsteady hand or that his tool was 

 dull and had slipped a little. 



Incidentally, while we have the globe before us it is interesting to 

 note that on this scale the difference between a sphere and the oval 

 shape we referred to could hardly be detected. It works out something 



