This remarkable scheme embodies the last notable attempt to solve the great dome problem with which the architects of the Renaissance had struggled from the time of Brunelleschi. But the problem is incapable of a satisfactory solution. It is impossible to make a large unbuttressed dome stand securely except by the extraneous means of binding chains. Wren has not attempted to do such a thing. He was too good an engineer to follow in the footsteps of Brunelleschi and Michael Angelo. His dome is well buttressed, but it is therefore necessarily hidden from view. To raise another dome of masonry from the cornice of the drum for external effect, and to crown such a dome with a stone lantern fifty feet high, he saw to be impossible with safety. A semblance of such a dome was, however, necessary to his scheme. He had been charged to make a dome “conspicuous above the houses,” and he therefore surrounded the cone, the true support of the lantern, with a wooden counterfeit of a dome upon which he makes the beholder believe that the lantern rests. The system is thus a monstrous architectural deceit. We have criticised Michael Angelo for springing a great dome from the top of a drum, but he cannot be reproached for deception. His dome is a real dome of masonry, and does carry the lantern as it appears to, though, as we have seen, insecurely, except for so long as the binding chains can be made to save it from collapse. Wren would not build a dome in this inherently weak manner. He preferred to design his masonry construction on sound principles, which would not allow an external dome, and to enclose this within the wooden counterfeit. And it may here be remarked that most modern domes, modelled after St. Peter’s and St. Paul’s, are wooden constructions and carry lanterns of wood. They are thus entirely safe, but they have not the monumental character of great architectural works. In general external effect the dome of St. Paul’s has much merit, if it does not justify the extravagant remark of Mr. Loftie that it is the “noblest dome in Christendom.”[177] [Illustration: FIG. 137.--Vaulting of St. Paul’s.] [Illustration: Plate XII INTERIOR OF ST. PAUL’S London]