In circuit, undetermined square or round;
in the Tenth Book it is determined, and is square. It is bounded by battlements of living sapphire, and towers of opal. In the midst is situated a Mount, the dwelling place of the Most High, surrounded by golden lamps, which diffuse night and day alternately--for without twilight and dawn, his dearest memories, Heaven would have been no Heaven to Milton. On a mountain far to the north of this great plain, Satan erects his pyramids and towers of diamond and gold, and establishes his empire, which lasts exactly three days. At his final overthrow the crystal wall of Heaven rolls back, disclosing a gap into the abyss; the rebels, tortured with plagues and thunder, fling themselves in desperation over the verge. They fall for nine days, through Chaos. Chaos is the realm of a king of the same name, who reigns over it with his consort Night. It is of immeasurable extent, quite dark, and turbulent with the raw material of the Cosmos. Just as Milton, for the purposes of his poem, followed the older astronomy, and gave to it a new lease of life in the popular imagination, so also he abides by the older physics. The orderly created World, or Cosmos, is conceived as compounded of four elements, Earth, Air, Fire, and Water. None of these four is to be found in Chaos, for each of them is composed of the simpler atoms of Hot, Cold, Moist, and Dry, symmetrically arranged in pairs. Thus Air is Hot and Moist, Fire is Hot and Dry, Water is Cold and Moist, Earth is Cold and Dry. Before they are separated and blended by Divine command, the four rudimentary constituents of creation are crowded in repulsive contiguity; they bubble and welter, fight and jostle in the dark, with hideous noises. In its upper strata Chaos is calmer, and is faintly lighted by the effulgence from the partially transparent walls of Heaven.
Below is Hell, newly prepared for the rebels. Like Heaven it is a vast plain; a bituminous lake, played over by livid flames, is one of its principal features; and hard by stands a volcanic mountain, at the foot of which the devils build their palace, and hold their assembly. The nine-fold gates of Hell, far distant, are guarded by Sin and Death, the paramour and the son of Satan. No one has plausibly explained how they came by their office. It was intended to be a perfect sinecure; there was no one to be let in and no one to be let out. The single occasion that presented itself for a neglect of their duty was by them eagerly seized.
During the nine days while the rebels lay on the burning lake, drowsed by its fumes, the World was created. It consists, according to the astronomy followed by Milton, of ten concentric spheres fitted, like Chinese boxes, one within another, and the Earth in the centre. Nine of these are transparent, the spheres, that is to say, of the seven planets (the Sun and the Moon being reckoned as planets), the sphere of the fixed stars, and the crystalline sphere. The outermost sphere, or primum mobile, is opaque and impervious. The whole orbicular World hangs by a golden chain from that part of the battlements of Heaven whence the angels fell. It is connected with Heaven by richly jewelled stairs, to be let down or taken up at pleasure, and can be entered only through an orifice or passage at the top. Between the foot of the stairs and the entrance to the World is a sea or lake of jasper and liquid pearl.
All the interest and meaning of the World is centred in one favoured spot of Earth. Eden is a district of Mesopotamia, and the happy garden, called Paradise, is situated in the east of Eden. It is a raised table-land, surrounded on all sides by a high ridge of hill, thickly wooded, and impenetrable. Its single gate, hewn out of a rock of alabaster, faces eastward, and is accessible only by a pass leading up from the plain and overhung by craggy cliffs. Through Eden runs a river which passes by a tunnel under Paradise, and, rising through the porous earth, waters the garden with springs. It was by this underground passage that Satan entered the garden a second time, when, having been discovered by Ithuriel, and expelled by Gabriel, he had circled the Earth seven times, keeping on the shady side to avoid the gaze of Uriel, and at the end of the week had resolved on another attempt.
The Fall of Man wrought some few changes in the physical configuration of the Universe. Sin and Death built the mighty causeway that connects the orifice of the World with Hell-gates. Provision had to be made under the new dispensation for the peopling of the whole surface of the Earth; so the axis was turned askew, and the beginning ordained of extremes of cold and heat, of storms and droughts, and noxious planetary influences. Night and day were known to man in his sinless state, but the seasons date from his transgression.
The time-scheme of the poem is less carefully defined; indeed, it is not certain that Milton intended accurately to define it. The recurrence of the numbers three and nine, numbers traditionally honoured by poetry, throws suspicion on the efforts of the exact commentators. Even in his statements with regard to spatial relations the poet was not always minutely consistent with himself. The distance from the plain of Heaven to the plain of Hell is said in the First Book to be three times the radius of the World, or, in his own words, the prison of Hell is
As far removed from God and light of Heaven
As from the centre thrice to the utmost pole.
The great globe, therefore, that hangs from the floor of Heaven reaches two-thirds of the way down to Hell. Yet in the Second Book Satan, after a long and perilous journey from Hell, comes in view of