vni FURTHER PROOFS 59 



a single voice resounds at the same moment 

 through whole cities; light does not creep forth 

 little by little, but is shed simultaneously over the 

 whole world. 



IX 



AGAIN, how could water be subject to tension i 

 without the aid of air ? You entertain no doubt, I 

 suppose, that the jet of water in the amphitheatre, 

 which is thrown from the centre of the arena to 

 the highest pinnacle, is accompanied by tension of 

 the water ? And yet neither hand 1 nor any other 

 engine can send or force water more effectively 

 than air. It lends itself readily to the influence of 2 

 the air, by the compelling force of which within the 

 pipe it is raised. Its nature is to flow down, but 

 under pressure it mounts and accomplishes great 

 results contrary to its nature. Yes, and do not 

 heavily laden vessels also prove that it is the 

 resistance of air, not of water, that prevents their 

 sinking ? The water of itself would give way, 

 and would be unable to bear up the burthens, were 

 it not itself upborne. So, too, a quoit thrown from 3 

 a height into a pond does not fall straight in, but 

 recoils, and that merely because the air bears it 

 back. In what way, again, could the sound of a 

 voice be transmitted through the thick barrier of a 

 wall unless the solid masonry contained some air 

 to receive and transmit the sound from without ? 

 The tension of the air, of course, affects not only 

 what is exposed, but what is concealed and enclosed 

 as well. This is easy for it to do, since it is never 4 

 divided, but maintains an unbroken continuity even 



1 A conjecture widely adopted gives "crane." 



