The book contains but five pages, of which the most beautiful is a design of a boy and girl with arms wound around each other, running over a hill-top, with a passionate sunset sky behind them. The "Book of Los," which must not be confounded with the Song, appeared in the same year. The Print Room has no copy, so we must descend to the Library, which happily possesses one. It consists of four chapters on the old themes, written in a sort of metrical prose. The frontispiece, representing a woman in the characteristic attitude so often adopted by Blake--the figure being seated on the ground, with head supported on knees in a mysterious lone place among rocks--is an arresting and powerful design. The writing in this book is particularly fine and clear. It is the last of Blake's "London Books of Prophecy." [Illustration: THE ACCUSERS: OR, SATAN'S TRINITY Colour-print from the Large Book of Designs in the Print Room] What shall I say of "Jerusalem, the Emanation of the Giant Albion"--this longest and perhaps most mystical of all Blake's dithyrambic books? It was written, as well as the "Milton," during the Felpham period, though probably added to, and finally finished after his return to London. Those who have heard the extraordinary tone-poem called "Also sprach Zarathustra," by Richard Strauss, may not think it far-fetched to suggest a parallel between revolutionary, chaotic, yet somehow great music, such as it is, and the so-called poem of "Jerusalem." To the authors of both, the classical, the established forms of expression belonging to their respective arts, seem outworn, inadequate, cramped. They feared to trust the new wine of their fermenting ideas to the old bottles of recognized form, and each has invented for himself a way of escape--somewhat dangerous, nay, almost suicidal--from the pressure of precedent, law, and order. Strange harmonies, horrid discords, sweetness as of honey, to be succeeded by a sharp acridity like that of unripe lemons, great marshalled orchestral forms, and wild abortive sounds, tormenting alike to ear and heart, are to be discerned in "Zarathustra," not without irrational excitement, anger, dismay, and occasional delight on the part of the hearer. And in "Jerusalem" is it not much the same?