any propriety be called a dome, occurs over the crossing of nave and transept in the old cathedral of Salamanca in Spain (Fig. 28).[47] But this vault has a very different character from the imaginary one just described. It rises from the top of a high drum resting on pendentives, and is built on a system of salient converging ribs. The spaces between these ribs are vaulted over with courses of masonry slightly arched from rib to rib, and thus running in a direction perpendicular to that of the courses in a Gothic vault cell, as in _B_, Figure 27. A series of hollowed gores are thus formed which give a scalloped instead of a plain circular plan to the vault as a whole. But such a vault differs fundamentally from a Gothic vault. For the line of the crown of each cell is the steep segmental curve _ab_ in _A_, Figure 29. In other words, the vault as a whole is a hemisphere with its surface broken into shallow hollows like the gores of a melon. It is obvious that in a vault with cells so shaped the thrusts are as great at all points in the circumference as they are in a simple hemispherical dome, and that such a vault can have no Gothic character. To develop this into any real likeness to a Gothic vault, it would be necessary to reduce it to an unbroken circular plan by cutting off the scallops at its base so that it would fit into the circular drum, upon the inner surface of which it would now intersect in series of small arches, one for each hollowed gore, with its springing at the point _d_ and its crown at the point _c_. Then these arches would have to be raised by stilting and pointing until their crowns were brought up to the level, or near the level, of the point _b_ as in _B_ of the same figure. Thus the line _dc_, which represents the height of the arches in the first stage of this development, becomes the line _ac_ in the second stage. So long as the chord of the arc _bc_ is a steeply inclined line, the vaulting cells cannot bear upon the ribs, nor can the thrusts of the vault be concentrated in a Gothic way. [Illustration: FIG. 28.--Interior of dome of Salamanca.] [Illustration: _A_ FIG. 29. _B_] The vault of Salamanca is not a Gothic vault in any sense, though its rib system and its hollowed cells conform with the earliest stage of apsidal vault development leading to Gothic.[48] It is a dome, and like the larger dome of St. Peter’s, it is sprung from the top of the drum; but unlike St. Peter’s dome, it is powerfully abutted by turrets and dormers built against its springing and its haunch, and it is loaded at the crown with a cone of masonry, so that from without it looks like a stumpy spire, and not like a dome.[49]