ELEMENTS INTERCHANGEABLE 121 



well, too, be surprised that after so many breakers 

 have spent their force, any succeeding wave is left. 

 The truth is, nothing is ever exhausted that returns 3 

 upon itself (i.e. is self-supported). All the four 

 elements return alternately upon one another ; what 

 is lost in one is conserved by passing into another. 

 Nature, too, weighs her parts as if with nice adjust- 

 ment in the balance, lest their just proportion should 

 be disturbed and the world topple over into ruin 

 ( = lose its equilibrium). All elements are in all. 

 Air not only passes into fire, but it is never without 

 fire. Deprive it of its heat and it will grow stiff, 

 stagnant, hard. Air passes into moisture, but 

 nevertheless contains moisture. Earth yields both 4 

 air and water, and is never at any time devoid of 

 water any more than it is of air. 'The mutual 

 transition is the easier, because there is already an 

 admixture of the element to which the transition 

 is to be made. So (i), 1 then, the earth contains 

 moisture, which it forces out. (2) 1 It contains air, 

 which the darkness of its wintry cold condenses so 

 as to form moisture. (3) 1 By nature, too, it has 

 itself the power of changing into moisture : this 

 power it habitually exerts. 



XI 



You have still a difficulty, you say. If the causes i 

 giving rise to rivers and fountains are constant, why 

 are their waters sometimes dried up ? and why do 

 they sometimes appear in places where they did not 

 exist before ? Their routes, I should reply, are often 

 disturbed by earthquakes ; the channel is cut off by a 



1 The numerals here have no counterpart in the original. 



