452 THOUGHTS ON THE 



the minutest straw. Now in bodies of such immense bulk 

 and magnitude, that by the vastness of their dimensions they 

 can overcome the greatness of distance, and come into visi 

 bility ; it is evident from certain comets, that changes take 

 place as they move in the expanse of the heavens. I allude 

 to those comets, which have retained a certain unvaried 

 relation of position to the fixed stars, such as that which 

 in our own day appeared in Cassiopea. But as respects 

 the earth, after having penetrated into the interior recesses 

 of it, leaving that crust and mixture of substances which 

 composes its surface and contiguous parts, there seems to 

 exist there also an eternal immobility, analogous to that 

 supposed to be found in heaven. For it is beyond a doubt, 

 that if the earth underwent changes at an extreme depth 

 beneath its surface, the influence of such changes, even in 

 the region we tread, would produce greater calamities than 

 any we behold. Most earthquakes, certainly, and volcanic 

 eruptions, do not rise from a great but a very moderate 

 depth, since they affect such an inconsiderable part of the 

 surface. For in proportion as such visitations agitate a* 

 wider area of the earth s surface, in the same proportion 

 we are to suppose that their bases and primitive seats enter 

 deeper into the bowels of the earth. These earthquakes, 

 therefore, which are greater (in the extent of surface agitated 

 I mean, not in violence of tremefaction), and which but 

 rarely happen, may be assimilated to comets of the des 

 cription we have mentioned, which are also unusual. So 

 that the proposition with which we set out remains un 

 shaken, namely, that between heaven and earth there is no 

 great difference as respects stability and change. But if 

 any one is influenced to a different opinion by the regularity 

 and seeming exactness of the motion of the heavenly bodies, 

 we have before us the ocean, the solitary handmaid as it 

 were of eternity, which exhibits no less unchangeable uni 

 formity than they. Lastly, if any one shall still insist, that 

 nevertheless it cannot be denied, but that on the surface of 

 the globe, and the part contiguous to it, changes innume 

 rable take place, but that in heaven it is not so, we would 

 have him thus answered ; that we do not carry the parallel 

 through every part; and yet if we take the upper and 

 middle regions of air (as they are termed) for a surface and 

 exterior integument of heaven, just as among us we regard 

 that space over which are distributed animals, plants, mi 

 nerals, as a surface or outer integument of earth, we behold 

 in both manifold reproductions and vicissitudes, in full 



