=The Dome.=--A vertical section of the dome of the Rotunda would show an exact half circle, with a diameter of one hundred feet. As has been said before, the dome is of stucco, applied to a framework of iron and steel, filled in with terra cotta. Although, as previously described, it appears to rest upon the deep upper entablature, it really springs immediately from the eight arches resting upon the great piers. The entablature, as will be seen on a close inspection, bears no part in the construction. It is projected so far forward from the dome that one may easily walk between the two. The entablature is about seven feet high, with a richly moulded architrave and a heavy projecting cornice. The ground of the frieze is gilt, with a relief ornament in white of eagles standing upon hemispheres and holding in their beaks a heavy garland of laurel. Over the north, south, east, and west arches, are two female figures--the work of Mr. Philip Martiny--represented as seated upon the architrave moulding and supporting a heavy cartouche--another instance of the emphasis which the architect has so often placed upon the four main axes of the building. [Illustration: HALF FIGURES. BY ALBERT WEINERT.] =The Stucco Ornamentation.=--The dome is so simply planned that a description of its main features may be given in a very brief space. The surface is filled with a system of square coffers. The ornamentation of the body of the dome is in arabesque. The eight ribs which mark off the dome into compartments are each divided into two by a band of gilded ornament resembling a guilloche. The coffers diminish in size from four and a half feet square at the bottom to two and a half feet at the top. The total number of coffers is three hundred and twenty--or forty in each compartment, and also in each horizontal row, and eight in each vertical row. The ground of the coffers is blue, the sky-color, as if one were really looking out into the open air--and therefore the color traditionally used in coffering. To give sparkle and brilliancy, many shades and kinds of blue are used, the darker and heavier at the bottom, and the lighter and airier toward the top. The transition is so gradual and natural that the eye does not perceive any definite change, but only a generally increased vividness. The border mouldings of the coffers are cream-colored--old ivory is the usual term--strongly touched with gold, and in the centre of each is a great gold rosette.