Kathleen Raine adds to the concept of the relationship of the parts to the whole in this passage from her biography Blake.
"Blake's 'visions' do not belong to time, but to the timeless; they are related as parts to the whole, but as parts of the surface of the sphere, all equidistant from the center, rather than in the time sequence to which in this world we are normally confined. Like dreams, they come to him in single symbolic episodes, or images; there is some attempt at chronology, but the material does not lend itself to this order, any more than would a series of dreams, all relating to an unfolding situation, but not forming a consecutive narrative. Blake added to Jerusalem over many years, inserting passages which may be fine in themselves but which further destroyed the continuity."
We can think of 'time' in the system of fourfold of which Blake was so fond.
Dimensionless: Time is the isolated fleeting moment, the point without extension. This is the only time we possess, the now which is ours to use and lose.
Milton, Plate 28 , (E 127) "Every Time less than a pulsation of the artery Is equal in its period & value to Six Thousand Years. Plate 29  For in this Period the Poets Work is Done: and all the Great Events of Time start forth & are concievd in such a Period Within a Moment: a Pulsation of the Artery.
1 Dimension: Moments strung together give us the thread of time which records the passing of time. Thought identifies the personal span of time into before and after. The individual follows his thread without deviation.
Jerusalem, Plate 20, (E 165) "Vala replied weeping & trembling, hiding in her veil. When winter rends the hungry family and the snow falls: Upon the ways of men hiding the paths of man and beast, Then mourns the wanderer: then he repents his wanderings & eyes The distant forest; then the slave groans in the dungeon of stone. The captive in the mill of the stranger, sold for scanty hire. They view their former life: they number moments over and over; Stringing them on their remembrance as on a thread of sorrow. Thou art my sister and my daughter! thy shame is mine also! Ask me not of my griefs! thou knowest all my griefs. Jerusalem answer'd with soft tears over the valleys."
2 Dimensions: The thread of each individual's time line is not isolated. Other time lines have their simultaneous moments and movements. A fabric is woven which becomes a plane of moments in lives, forming a surface with contributions from multiple lives.
Jerusalem, Plate 83, (E 242) "So Los spoke. to the Daughters of Beulah while his Emanation Like a faint rainbow waved before him in the awful gloom Of London City on the Thames from Surrey Hills to Highgate: Swift turn the silver spindles, & the golden weights play soft And lulling harmonies beneath the Looms, from Caithness in the north To Lizard-point & Dover in the south: his Emanation Joy'd in the many weaving threads in bright Cathedrons Dome
Weaving the Web of Life for Jerusalem. The Web of Life Down flowing into Entuthons Vales glistens with soft affections."
3 Dimensions: A matrix develops when to the two dimensions of the plane are added the past and future. To everywhere and everyone is added everytime. In Blake's matrix nothing is lost, everything is permanent.
Milton, Plate 22 , (E 117) 'I am that Shadowy Prophet who Six Thousand Years ago Fell from my station in the Eternal bosom. Six Thousand Years Are finishd. I return! both Time & Space obey my will. I in Six Thousand Years walk up and down: for not one Moment Of Time is lost, nor one Event of Space unpermanent But all remain: every fabric of Six Thousand Years Remains permanent: tho' on the Earth where Satan Fell, and was cut off all things vanish & are seen no more They vanish not from me & mine, we guard them first & last The generations of men run on in the tide of Time But leave their destind lineaments permanent for ever & ever. So spoke Los as we went along to his supreme abode."
End of Time: Time ends when it is swallowed up in Eternity. Enitharmon's loom no longer weaves the web of material life. Consciousness on longer resides in the minds of men, but the minds of men reside in the great consciousness from Eternity to Eternity.
Jerusalem, Plate 92, (E 252) "So Los spoke. Enitharmon answerd in great terror in Lambeths Vale The Poets Song draws to its period & Enitharmon is no more. For if he be that Albion I can never weave him in my Looms But when he touches the first fibrous thread, like filmy dew My Looms will be no more & I annihilate vanish for ever Then thou wilt Create another Female according to thy Will. Los answerd swift as the shuttle of gold. Sexes must vanish & cease To be, when Albion arises from his dread repose O lovely Enitharmon:"
River of Life