Journal of Roman Studies

Research Article

The Casting Technique of Romano-British Lead Ingots

G. Clement Whittick

The striations visible on the side and end surfaces of Romano-British ingots of lead aroused comment at an early date. They have sometimes been explained in the past as caused by the grain of wood used as a pattern for the mould—an explanation which neither accords well with their actual appearance as seen on many ingots nor with a variety of technical evidence now available which leads to the almost certain conclusion that the moulds were made of smoothed clay: but more generally the striations have been held to prove that casting was done plecemeal by the ladling of a series of small batches of metal into the mould, and early writers thus claim to have discerned from nine or ten up to twenty-seven or thirty ‘layers’ produced in ingots by such a method. This was the view categorically stated by W. Gowland in his important study of Roman lead at the beginning of this century: ‘Roman lead smelting furnaces used in Britain did not possess tap-holes, but … the lead was taken out … by means of a ladle,’ and he went on to say that the structure of many of the ingots reveals that they ‘consist not of solid blocks of lead, but of a series of distinct layers, tolerably uniform in thickness, which can be more or less easily separated from one another. Such a structure can only have been produced by pouring the lead into the mould in successive portions with a sufficient interval of time between each to allow of one solidifying before the next was added’.