inexpressible color in the world,--the color of glass, of transparent alabaster, of polished marble, and lustrous gold. It would be easier to illustrate a crest of Scottish mountain, with its purple heather and pale harebells at their fullest and fairest, or a glade of Jura forest, with its floor of anemone and moss, than a single portico of St. Mark's. The fragment of one of its archivolts, given at the bottom of the opposite Plate, is not to illustrate the thing itself, but to illustrate the impossibility of illustration. SECTION XLIX. It is left a fragment, in order to get it on a larger scale; and yet even on this scale it is too small to show the sharp folds and points of the marble vine-leaves with sufficient clearness. The ground of it is gold, the sculpture in the spandrils is not more than an inch and a half deep, rarely so much. It is in fact nothing more than an exquisite sketching of outlines in marble, to about the same depth as in the Elgin frieze; the draperies, however, being filled with close folds, in the manner of the Byzantine pictures, folds especially necessary here, as large masses could not be expressed in the shallow sculpture without becoming insipid; but the disposition of these folds is always most beautiful, and often opposed by broad and simple spaces, like that obtained by the scroll in the hand of the prophet seen in the Plate. The balls in the archivolt project considerably, and the interstices between their interwoven bands of marble are filled with colors like the illuminations of a manuscript; violet, crimson, blue, gold, and green alternately: but no green is ever used without an intermixture of blue pieces in the mosaic, nor any blue without a little centre of pale green; sometimes only a single piece of glass a quarter of an inch square, so subtle was the feeling for color which was thus to be satisfied. [Footnote: The fact is, that no two tesserae of the glass are exactly of the same tint, the greens being all varied with blues, the blues of different depths, the reds of different clearness, so that the effect of each mass of color is full of variety, like the stippled color of a fruit piece.] The intermediate circles have golden stars set on an azure ground, varied in the same manner; and the small crosses seen in the intervals are alternately blue and subdued scarlet, with two small circles of white set in the golden ground above and beneath them, each only about half an inch across (this work, remember, being on the outside of the building, and twenty feet above the eye), while the blue crosses have each a pale green centre. Of all this exquisitely mingled hue, no plate, however large or expensive, could give any adequate conception; but, if the reader will supply in imagination to the engraving what he supplies to a common woodcut of a group of flowers, the decision of the respective merits of modern and of Byzantine architecture may be allowed to rest on this fragment of St. Mark's alone.