From a structural point of view Palladio’s scheme is an improvement on that of Padua. For in Padua, as in Vicenza, both stories of the portico are vaulted, and the slender columns which alone bear the vaulting are too weak to withstand the thrusts of this vaulting, and thus both transverse and longitudinal tie-rods are inserted to maintain the stability of the fabric. But Palladio’s massive and heavily weighted piers are strong enough to bear the thrusts without the aid of ties, and it may be added that the great orders have more function here than they usually have in Renaissance design, since their columns act somewhat as buttresses. The shaft of an order has not, indeed, a proper form for an abutment, and has no buttress expression. Its resistance to thrust is slight, but it is better than nothing at all. Following Sansovino, the architect has introduced a balustrade in each opening of the arcade, and a continuous one as a crowning feature of the cornice. Palladio himself thought well of this work, and he does not hesitate to say in his book that it will bear comparison with the most beautiful buildings of antiquity. He tells us, also, that it is constructed in the best manner out of excellent cut stone.[101] The last remark is significant, for genuine stone masonry was not always employed by Palladio in buildings which had the appearance of stone construction. The use of brick and rubble with a revetment of stucco had not been uncommon with the builders of the early Renaissance, and such materials were extensively employed even by Bramante and Michael Angelo. But Palladio went further than his predecessors in the creation of architectural shams. [Illustration: FIG. 75.--Loggia Bernarda.] Palladio was an earnest devotee of his art as he understood it, but he had what may be called a theatrical ideal of architecture. The superficial appearance was what chiefly concerned him. He had great versatility in scenic and structurally meaningless composition, and his numerous palace fronts in Vicenza are remarkable for their superficially varied character. The Palazzo Valmarana, with its colossal pilasters on a high podium overlapping a lesser order embracing the basement and mezzanine, while the great entablature is broken into ressauts over the pilasters; the Palazzo Colleone-Porta, with its basement wall rusticated over a plain dado and an Ionic order on the face of the superstructure; the Palazzo Porta-Barbarano, with its superimposed orders and elaborate ornamentation in stucco relief; and the Loggia Bernarda, with its gigantic composite order and balcony corbels in the form of Doric triglyphs (Fig. 75), are sufficient illustrations of this. The skin of stucco with which many of these buildings were originally covered has broken off in many places, revealing the poor materials of which they are built. [Illustration: FIG. 76.--Window of Palazzo Branzo.]