Scamilli impares

The words scamilli impares are sometimes left untranslated in editions of Vitruvius. They occur in contexts where small geometrical refinements are prescribed for the construction of Greek temples – the curvature of the stylobate or entasis of columns, for example. Opinion is divided as to whether scamilli were some sort of physical aids to the surveying process or were more abstract, such as a system of measurement. This paper examines the curvature of the stylobate of the Parthenon and concludes that scamilli, physical or abstract, were closely involved with the sicilicus, the (smallest) Roman (or Greek) unit of measurement, one quarter of an inch. (Numerical calculations are carried out in metric units and these are interpreted where necessary in terms of inches.)