vi ATMOSPHERIC "TENSION" 57 



through atmospheric tension that they display their 

 functions ? Or, let us note what an enormous force 5 

 is exerted in secret by quite tiny seeds, whose small- 

 ness has allowed them to find a lodgment in the 

 clefts of stones. Their slender diminutive roots 

 gather strength enough to dislodge huge boulders, 

 split statues, and cleave crags and rocks. And to 6 

 what is this due but air tension, without which 

 there is no strength, over which no strength can 

 prevail ? The unity of the atmosphere may, in fact, 

 be inferred from the mere coherence of our bodies. 

 What else is it that holds them together save air ? 

 What else is it by which the soul is stirred (literally, 

 moved) ? l What constitutes that motion if it be 7 

 not tension ? What tension can there be except 

 from unity? What unity could there be unless it 

 were in the air ? What else, too, brings forth from 

 the earth its fruits and slender grain, and sets erect 

 the verdant trees, and stretches out their branches, 

 or sets them on high, but the tension and unity 

 of air? 



VII 



SOME writers believe that the air is rent and sepa- i 

 rated into small parts with void spaces, as they 

 suppose, between. They consider the easy flight of 

 birds through it a proof that it has not a compact 

 body, but has large empty spaces : fowls, great and 

 small, pass through it without difficulty. But this is 

 a mistake. For water also affords the same easy 2 

 motion, and there is no doubt of its unity. When 

 it receives bodies, it always retreats in the direction 



1 Nisard translates, What imparts movement, in man, to the vital 

 principle ? 



