"I am the daughter of earth and water, And the nursling of the sky; I pass through the pores of the ocean and shores; I change, but I cannot die. For after the rain, when with never a stain The pavilion of heaven is bare, And the winds and sunbeams with their convex gleams, Build up the blue dome of air, I silently laugh at my own cenotaph, And out of the caverns of rain, Like a child from the womb, like a ghost from the tomb I arise and unbuild it again." How crammed are these lines with the purest Nature Mysticism as moderns understand it! The sense of living process reigns supreme. They are the offspring, not of fancy, nor even of imagination as ordinarily conceived--but of insight, of vision, of living communion with a living world. It is tempting, while dealing with the airy realms of cloud-land, to dwell at length on the mystic influence of the queen of aerial phenomena--the rainbow. That influence in the past has been immense; it still is, and ever will be, a power to be reckoned with. Science cannot rob it of its glories. The gold-winged Iris of Homer, swifter-footed than the wind, has passed. The Genesis story of "the bow in the cloud" may dissolve in the alembic of criticism--but the rainbow itself remains, still a sevenfold bridge of souls from this solid-seeming earth to a rarer land beyond. Who is there who cannot sympathise with Wordsworth? "My heart leaps up when I behold A rainbow in the sky. So was it when I was a child; So it is now I am a man; So let it be when I am old-- Or let me die." Tempting is it also to treat of the birds--the denizens of the air-- to comment on the exquisite trio of bird-poems, Wordsworth's "Cuckoo," Shelley's "Ode to a Skylark," and Keats' "Ode to a Nightingale." For assuredly it is the medium in which these delicate creatures pass their lives that gives them the chiefest share of their magic and their mystery. But this gem from Victor Hugo must suffice for all the tuneful choir: "Like a songbird be thou on life's bough, Lifting thy lay of love. So sing to its shaking, So spring at its breaking, Into the heaven above." The dome of air thus expands into the dome of heaven with its eternal fires, and bids us turn to the third of the ancient sages whose speculations are aiding our steps in this tentative study. CHAPTER XXVII HERACLEITUS AND THE COSMIC FIRE