[99] Early Hellenistic barrel vaults in the Mediterranean coast-lands. Delbrück, op. cit., pt. ii. Table A, p. 64. Cut stone vaults showing characteristics of brick construction, such as vaulting in concentric courses, vaults outlined by mouldings, vaults with uncentered joints, and a single example of the horse-shoe vault at Chiusi, idem, Table B, p. 67. In Egypt and in western Asia solutions were sought to further problems of stone vaulting, the intersection of stone barrel vaults, vaulting in inclined planes, the stone dome with or without voussoirs. At first these were in general confined to the East; the evolution in the West begins in the Roman Imperial period. Delbrück, pt. ii. pp. 77-80. Development of the Egyptian cut stone vault out of sun-dried brick construction, idem, pp. 80-3. [100] Delbrück, op. cit., pt. ii, Table C, p. 70. [101] Bridge at Pergamon, Delbrück, pt. ii, Table D, p. 72. [102] Andrae, _Hatra_, pt. ii, p. 2, assigns it to the second century, after Trajan and before Septimius Severus; a more accurate dating is not possible without excavation. The largest of the palace vaults spans 14·80 metres. [103] Choisy, _L’Art de bâtir chez les Byzantins_, p. 154. [104] Podium of the altar and of the upper gymnasium at Pergamon, Delbrück, pt. ii, p. 104. The whole subject is admirably handled by him, pt. ii, pp. 108-11, where the accounts left by Diodorus and by Strabo of the substructure of the Hanging Gardens are examined, and the mutual interaction of India and western Asia is considered. See Koldewey, _Das wieder erstehende Babylon_, p. 90, for a description of the vaulted substructions which he believes to have supported the Hanging Gardens. [105] Strabo, xvi, 1, 5. [106] Chaldaea, at Mughair, sun-dried brick; Perrot-Chipiez, vol. ii, p. 232. Egypt, at Dair el-Baḥri, 18th Dynasty; Perrot-Chipiez, vol. i, p. 536; and a brick dome at Abydos; Choisy, _Histoire de l’Architecture_, vol. i, p. 19. Syria, dolmenic tomb at Ridjm el Melfûf; _Annual of the Palestine Exploration Fund, 1911_, p. 9. Knossos; Evans, _Prehistoric Tombs of Knossos_, p. 139. Numerous other examples are cited by Durm in two articles in the _Jahreshefte des öst. arch. Instituts_, vol. x, 1907. [107] _Mitt. der D. O.-G._, No. 27, p. 29. [108] In one of these only is the springing of the vault preserved. Bell, _Amurath to Amurath_, Fig. 109. [109] Sâmarrâ, _Amurath_, Fig. 154. [110] Cf. the stone vaults at Medinet Abu, Delbrück, op. cit., pt. ii, p. 81. [111] Dieulafoy, _L’Art antique de la Perse_, vol. iv, Fig. 10; _Mitt. der D. O.-G._, No. 40, Fig. 10, a late Assyrian tomb. [112] Dieulafoy, _L’Art antique_, vol. iv, Plate 7. [113] Bell, _Churches and Monasteries of the Ṭûr ‘Abdîn_, p. 100 (44). [114] Idem, pp. 65 (9), 71 (15), &c. [115] Mau, _Pompeii, its Life and Art_, p. 199. [116] Delbrück, op. cit., pt. ii, Fig. 45. [117] Idem, p. 146.