Besides, the earth, when of a sudden shook By the big thunder, doth with her motion shake All that's above her--which she ne'er could do By any means, were earth not bounden fast Unto the great world's realms of air and sky: For they cohere together with common roots, Conjoined both, even from their earliest age, In linked unison. Aye, seest thou not That this most subtle energy of soul Supports our body, though so heavy a weight,-- Because, indeed, 'tis with it so conjoined In linked unison? What power, in sum, Can raise with agile leap our body aloft, Save energy of mind which steers the limbs? Now seest thou not how powerful may be A subtle nature, when conjoined it is With heavy body, as air is with the earth Conjoined, and energy of mind with us? Now let us sing what makes the stars to move. In first place, if the mighty sphere of heaven Revolveth round, then needs we must aver That on the upper and the under pole Presses a certain air, and from without Confines them and encloseth at each end; And that, moreover, another air above Streams on athwart the top of the sphere and tends In same direction as are rolled along The glittering stars of the eternal world; Or that another still streams on below To whirl the sphere from under up and on In opposite direction--as we see The rivers turn the wheels and water-scoops. It may be also that the heavens do all Remain at rest, whilst yet are borne along The lucid constellations; either because Swift tides of ether are by sky enclosed, And whirl around, seeking a passage out, And everywhere make roll the starry fires Through the Summanian regions of the sky; Or else because some air, streaming along From an eternal quarter off beyond, Whileth the driven fires, or, then, because The fires themselves have power to creep along, Going wherever their food invites and calls, And feeding their flaming bodies everywhere Throughout the sky. Yet which of these is cause In this our world 'tis hard to say for sure; But what can be throughout the universe, In divers worlds on divers plan create, This only do I show, and follow on To assign unto the motions of the stars Even several causes which 'tis possible Exist throughout the universal All; Of which yet one must be the cause even here Which maketh motion for our constellations. Yet to decide which one of them it be Is not the least the business of a man Advancing step by cautious step, as I.