Internally perhaps the greatest defect of the building is a want of height in the perpendicular part, which the dome appears to overpower and crush. This mistake is aggravated by the lower part being cut up into two storeys, an attic being placed over the lower order. The former defect may have arisen from the architect wishing to keep the walls in some proportion to the portico. The latter is a peculiarity of the age in which I suppose this temple to have been remodelled, when two or more storeys seem to have become indispensable requisites of architectural design. We must ascribe also to the practice of the age the method of cutting through the entablature by the arches of the great niches, as shown in the sectional part of the last woodcut. It has already been pointed out that this was becoming a characteristic of the style at the time when the circular part of this temple was arranged as it at present appears. Notwithstanding these defects and many others of detail that might be mentioned, there is a grandeur and a simplicity in the proportions of this great temple that render it still one of the very finest and most sublime interiors in the world, and the dimensions of its dome, 145 ft. 6 in. span by 147 in height, have not yet been surpassed by any subsequent erection. Though it is deprived of its bronze covering[170] and of the greater part of those ornaments on which it mainly depended for effect, and though these have been replaced by tawdry and incongruous modernisms, still nothing can destroy the effect of a design so vast and of a form so simply grand. It possesses moreover one other element of architectural sublimity in having a single window, and that placed high up in the building. I know of no other temples which possess this feature except the great rock-cut Buddhist basilicas of India. In them the light is introduced even more artistically than here; but, nevertheless, that one great eye opening upon heaven is by far the noblest conception for lighting a building to be found in Europe. Besides this great rotunda there are two other circular temples in or near Rome. The one at Tivoli, shown in plan and elevation in the annexed woodcuts (Nos. 192 and 193), has long been known and admired; the other, near the mouth of the Cloaca Maxima, has a cell surrounded by twenty Corinthian columns of singularly slender proportions. Both these probably stand on Etruscan sites; they certainly are Etruscan in form, and are very likely sacred to Pelasgic deities, either Vesta or Cybele. [Illustration: 192. Plan of Temple at Tivoli. Scale 100 ft. to 1 in.] [Illustration: 193. Restored Elevation of Temple at Tivoli. Scale 50 ft. to 1 in.]