One of the most impressive technological developments in the ancient Near East during the fourth and third millennia B.C.E. was the invention of lost-wax casting for making objects of metal or, later, glass. The artisan begins by sculpting a wax model, which is then covered with clay and fired, causing the wax to melt out through channels pierced through the clay. Molten metal (or glass) is then poured into the mold through these channels, which also allow hot gases to escape. A sizable mold requires a large amount of metal, which was expensive in ancient Mesopotamia because it had to be imported. To reduce the amount of metal used, the wax can be sculpted over a core of clay. This core is held in place after the wax is removed from the mold and during the casting by metal supports inserted through...