The great advantage to be derived from the mode of constructing domes just described was the power it gave of placing them on pillars without having anything to fear from the lateral thrust of the vault. The Romans never even attempted this, but always, so to speak, brought their vaults down to the ground, or at least could only erect them on great cylinders, which confined the space on every side. The Byzantine architects, as we have seen, cut away a great deal of the substructure, but nevertheless could never get rid of the great heavy piers they were forced to employ to support their domes, and in all ages were forced to use either heavy abutments externally, or to crowd their interiors with masses of masonry, so as in a great measure to sacrifice either the external effect or the internal convenience of their buildings to the constructive exigencies of their domes. This in India never was the case; all the pressure was vertical, and to ensure stability it only required sufficient strength in the support to bear the downward pressure of the mass--an advantage the importance of which is not easily over-estimated. One of the consequences of this mode of construction was, that all the decoration of the Indian domes was horizontal, or, in other words, the ornaments were ranged in concentric rings, one above the other, instead of being disposed in vertical ribs, as in Roman or Gothic vaults. This arrangement allows of far more variety without any offence to good taste, and practically has rendered some of the Indian domes the most exquisite specimens of elaborate roofing that can anywhere be seen. Another consequence of this mode of construction was the employment of pendants from the centres of the domes, which are used to an extent that would have surprised even the Tudor architects of our own country. With them, however, the pendant was an architectural _tour de force_, requiring great constructive ingenuity and large masses to counterbalance it, and is always tending to destroy the building it ornaments; while the Indian pendant, on the contrary, only adds its own weight to that of the dome, and has no other prejudicial tendency. Its forms, too, generally have a lightness and elegance never even imagined in Gothic art; it hangs from the centre of a dome more like a lustre of crystal drops than a solid mass of marble or of stone. [Illustration: 117. Diagram of the arrangement of the pillars of a Jaina Dome.] [Illustration: 118. Diagram Plan of Jaina Porch.]