Analysis of Milton: The Sky is an Immortal Tent Built by the Sons of Los

The sky is an immortal tent built by the Sons of Los:
     And every space that a man views around his dwelling-place
     Standing on his own roof or in his garden on a mount
    Of twenty-five cubits in height, such space is his universe:
    And on its verge the sun rises and sets, the clouds bow
    To meet the flat earth and the sea in such an order'd space:
     The starry heavens reach no further, but here bend and set
    On all sides, and the two Poles turn on their valves of gold:
  And if he moves his dwelling-place, his heavens also move
  Where'er he goes, and all his neighbourhood bewail his loss.
 Such are the spaces called Earth and such its dimension.
 As to that false appearance which appears to the reasoner
 As of a globe rolling through voidness, it is a delusion of Ulro.
The microscope knows not of this nor the telescope: they alter
The ratio of the spectator's organs, but leave objects untouch'd.
  For every space larger than a red globule of Man's blood
 Is visionary, and is created by the Hammer of Los;
 And every space smaller than a globule of Man's blood opens
 Into Eternity of which this vegetable Earth is but a shadow.
The red globule is the unwearied sun by Los created
 To measure time and space to mortal men every morning