These different types of structure may perhaps be illustrated by three different books, all belonging to the intermediate ground between science and art. I should say that Buckle's "History of Civilization," with all its wealth and vigor, is exceedingly loose-jointed in all its logical structure, and also very defective in its literary structure, although it happens to have an element of freshness which is rare in such a work, and carries the reader along. Darwin's "Origin of Species" is better; that has at the bottom a strong logic, whether conclusive or otherwise, but is so rambling and confused in its merely literary statement, that it does itself no justice. A third book, Huxley's "Lectures," combines with its logic a power of clear and symmetrical statement that gives it a rare charm, and makes it a contribution, not to science alone, but to literature. In what is called poetry, _belles-lettres_ or pure literature, the osseous structure is of course hidden; and the symmetry suggested is always that of taste rather than of logic, though logic must be always implied, or at least never violated. In some of the greatest modern authors, however, there are limitations or drawbacks to this symmetry. Margaret Fuller said admirably of her favorite Goethe, that he had the artist's hand, but not the artist's love of structure; and in all his prose writings one sees a certain divergent and centrifugal habit, which completely overpowers him before the end of "Wilhelm Meister," and shows itself even in the "Elective Affinities," which is, so far as I know, his most perfect prose work. In Emerson, again, one observes a similar defect; his unit of structure is the sentence, and the periods seem combined merely by the accident of juxtaposition; each sentence is a pearl, and the whole essay is so much clipped from the necklace; but it is fastened at neither end, and the beads roll off. Yet it is not enough for human beauty to possess symmetry of structure, within and without: there must be a beautiful coloring also, wealth of complexion, fineness of texture. So the next element of literary art lies in the _choice of words_. Style must have richness and felicity. Words in a master's hands seem more than words; he can double or quadruple their power by skill in using; and this is a result so delightful, as to give to certain authors a value out of all proportion to their thought. There are books which are luxuries, _livres de luxe_, whose pages seem builded of more potent words than those of common life. Keats, for example, in poetry, and Landor in prose, are illustrations of this; and perhaps the representative instance, in all English literature, of the prismatic resources of mere words is the poem of "The Eve of St. Agnes." But thus to be crowned monarch of the sunset, to trust one's self with full daring in these realms of glory, demands such a balance of endowments as no one in English literature save Shakespeare has attained.