It is somewhat uncertain whence they obtained their silver; in a letter of Lu-enna to Enitarzi, a ruler who apparently flourished shortly after the first dynasty of Lagash, silver is mentioned as forming part of the booty taken from Elam, and in later times it was one of the principal items of tribute exacted by the Assyrian kings from their vassal princes, and as such, is frequently mentioned on the Black Obelisk of Shalmaneser II. The excavations have yielded very few relics made of this material, the reason again being probably due to the predatory raids of booty-hunters. Of smaller objects belonging to the Assyrian period may be mentioned a silver bell with a bronze clapper, a silver ring set with a garnet, and a silver bracelet, all in the British Museum, but the dates of these are unfortunately quite uncertain. That it was used extensively, however, is shown not only by the important place which it occupies in the tribute brought by subject tribes and peoples, but also by the allusions made to this metal in the royal inscriptions. Thus Esarhaddon informs us that he covered the doors of one of his palaces with this precious metal. Idols were also sometimes made of silver as well as of gold, to both of which classes Tiglath-Pileser I makes allusion in one of his inscriptions.[119] With two of the so-called “baser metals” we have already had occasion to deal at some length, owing to the important part they played in the civilization of the Babylonians and Assyrians, but we have tangible as well as linguistic evidence of their acquaintance with and utilization of other metals as well as gold, silver, copper and bronze. It has been shown that lead was sometimes used as an alloy, but it was sometimes used in its unmixed state; a very interesting example of its use in this latter condition is to be found in a gate-socket now preserved in the British Museum. The socket itself is made of bronze, but it is set in solid lead. The date of this unique object is uncertain, but it may probably be assigned to the Assyrian era. Few leaden objects have as yet been yielded by the excavations, though it is frequently mentioned as forming part of the tribute of subject peoples, and we know that it was used in the manufacture of colours, as well as being placed inside the hollow lion-weights found at Nimrûd to add the specific gravity required. In Egypt lead would appear to have been known and used at a very early period, judging from the little statuette in the British Museum, which apparently dates from about the time of the First Dynasty, and is said to be made of solid lead.