In Venice we have some grand examples, at S. Mark’s, of this system of incrustation filling in the whole of the space within large arches; here it is lawful, because there is no weight upon it to thrust it out of its place or disjoint it, as the least pressure most certainly always will. So far in praise of the Venetian system. But in other parts of the same building we have this system carried to a length which I cannot but think most mistaken, and which, I most heartily trust, may never find imitators here. In these the arches were constructed in brick, and then entirely covered with marble. Of course there was some difficulty in doing this, and the way in which the difficulty was met was extremely ingenious; a succession of thin slabs of marble was placed round the soffeit of the arch, having perhaps enough of the cohesion given by the form of the arch to enable them to support their own weight, and further supported by metal staples let into the joints of the brickwork. The edges of these thin slabs projected sufficiently in advance of the face of the brickwork to allow of their being worked with some kind of pattern--generally, as has before been said, a sort of dentil--and of their giving some support to the thin slices of marble with which the walls were then covered. The whole system was excessively weak; and this can nowhere be better seen than in the Fondaco de Turchi, where almost the whole of the marble facing and beautiful medallions, in which it was once so rich, have peeled off, and left nothing but the plain and melancholy substratum of brick. Few architects, I should think, would like to contemplate their work perishing in this piecemeal manner, any more than they would enjoy the thought of a west front left unfinished, like that of Sta. Anastasia at Verona, and prepared only for marble with rough, irregular, and unsightly brickwork. It would be unjust not to say that often, very often, this system of incrustation, even when carried to the extreme limits of what seems to be lawful, wins upon our love by the exquisite delicacy and taste of the sculptured patterns, worked in low-relief, with which it is covered. The men who did this work were, perhaps, more of sculptors than of architects; and certainly it must be confessed that never in buildings in which the construction is mainly thought of, is there, so far as I know, so much elaborate thought and skill exhibited in the decorative part of the work as in buildings such as these. Sometimes, the sculptured medallions set in the centre of a plain surface of marble are of exquisite taste and beauty; whilst here and there, as e.g. in S. Mark’s and in one or two spots in the water-front of the Ducal Palace, are examples of great beauty, of medallions formed of marbles of various colours, arranged with great refinement in some kind of geometrical pattern, which shew another and equally beautiful mode of relieving plain spaces of walling.