The first series, "Songs of Innocence," was succeeded by "Songs of Experience," subsequently bound in one volume. Then came the book of "Thel," an allegory, wherein Thel, beautiful daughter of the Seraphim, laments the shortness of her life down by the River of Adona, and is answered by the Lily of the Valley, the Little Cloud, the Lowly Worm, and the Clod of Clay; the burden of whose song is-- "But how this is, sweet maid, I know not, and I cannot know, I ponder, and I cannot ponder: yet I live and love!" The designs give the beautiful daughter listening to the Lily and the Cloud. The Clod is an infant wrapped in a lily-leaf. The effect of the whole poem and design together is as of an "angel's reverie." The "Marriage of Heaven and Hell" is considered one of the most curious and original of his works. After an opening "Argument" comes a series of "Proverbs of Hell," which, however, answer very well for earth: as, "A fool sees not the same tree that a wise man sees"; "He whose face gives no light shall never become a star"; "The apple-tree never asks the beech how he shall grow, nor the lion the horse how he shall take his prey." The remainder of the book consists of "Memorable Fancies," half dream, half allegory, sublime and grotesque inextricably commingling, but all ornamented with designs most daring and imaginative in conception, and steeped in the richest color. We subjoin a description of one or two, as a curiosity. "A strip of azure sky surmounts, and of land divides, the words of the title-page, leaving on each side scant and baleful trees, little else than stem and spray. Drawn on a tiny scale lies a corpse, and one bends over it. Flames burst forth below and slant upward across the page, gorgeous with every hue. In their very core, two spirits rush together and embrace." In the seventh design is "a little island of the sea, where an infant springs to its mother's bosom. From the birth-cleft ground a spirit has half emerged. Below, with outstretched arms and hoary beard, an awful, ancient man rushes at you, as it were, out of the page." The eleventh is "a surging of mingled fire, water, and blood, wherein roll the volumes of a huge, double-fanged serpent, his crest erect, his jaws wide open." "The ever-fluctuating color, the spectral pigmies rolling, flying, leaping among the letters, the ripe bloom of quiet corners, the living light and bursts of flame, the spires and tongues of fire vibrating with the full prism, make the page seem to move and quiver within its boundaries, and you lay the book down tenderly, as if you had been handling something sentient."