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JULY, 1915]
THE DOME IN PERSIA
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I will now briefly describe Sarvistân. It measures 120 feet by 140, and has three domes which are shown here in plan and in section. (Figs. 7 and 8) The
OPEN walls are built of stone, the domes being of brick, but practically all the stucco decoration has disappeared. A great advance in scientific knowledge is shown in the vaulting arrangements. In order to lessen the thrust of the elliptical barrel vaults, and to avoid very thick side walls, piers were built within the
Fig. 7. walls, thus forming a series of recesses. (Plate I, B.) These recesses, be it specially noticed, are nothing more than a development of the method employed at Firûzâbâd, by which the hollow spaces left in the thickness of the walls in the former building, are here utilised to add to the floor-space of the hall itself.
Fig. 4 These piers do not carry transverse arches, but support instead either semidomes or barrel vaults over the recesses between them, above which rises the central elliptical vault, its span being reduced by this arrangement from 26 feet (the extreme width of the hall) to about 17. (Fig. 9). The lower portion of these piers is carried on coupled columns, which give increased space; so that the builders must have recognised the fact that, the thrust being resisted, the actual weight can be borne by supports of less superficial area than the piers themselves. As the recesses are of course rectangular, squinches are used in the angles to carry the semi-domes over them.
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