Tangs show that the shaft was a reed, sockets show that it was of wood.
Inscriptions of Lugal-zaggisi and Lugal-kigub-nidudu, kings of Erech and Ur respectively, and of other early pre-Semitic rulers, on door-sockets and stone vases, show the veneration in which the ancient shrine was then held and the importance attached to its possession, as giving a certain stamp of legitimacy.
This joint is durable, secure and easily made; it allows for expansion and by its use the risk of pipe sockets being cracked is avoided.
The anterior margin of the sternum, between the right and left anterior lateral processes receives in sockets the feet of the coracoids.
This method, however, was not found satisfactory: the projecting feet were liable to be broken off, and in 1799 or 1800 Jessop abandoned them, using instead separate cast-iron sockets or chairs, which were fastened to the sleepers and in which the rails were supported in an upright position.