Harold Bloom discusses the transition "from the confrontation" of Emilia "to history," which "is gradual and inconstant until the passage beginning with line 190. What begins as history at line 71 passes rapidly into a rhapsody of images again, descends yet once more into the realization of the limits of expression, and climaxes in three passages of high rhetoric, sermons on love" (213). Let's look at what Bloom has to say specifically about lines 72-82:
We are back to the "Life of Life" lyric celebrating Asia's transformation in this account of the meeting with Emilia. The language of rapturous paradox is employed to convey a reality which transcends the world of our experience, the world in which we appropriate for ourselves. The shared reality of relationship, in which what is loved cannot be imaged for fear that self-appropriation may commence, is represented here by the irony of a figure of the loved one which cannot be apprehended, strictly speaking. As in the "Life of Life" lyric, the reader is confronted by a divine brightness trembling through limbs, but the limbs themselves are the only evidence for such brightness, and tremble through the brightness. The Thou cannot become an It, if we are given no object toe experience, but the poem demands a figure, a verbal object. Only paradox can provide a figure which is no figure, in which the outer covering and the essence contained are interchangeable, and therefore scarcely to be grasped before they have passed over into each other once again. (213)
Bloom, Harold. Shelley's Mythmaking. Ithaca: Cornell UP, 1969.