In this chapter I want to re-examine some of the structural characteristics of certain types of lexical fields, with a view to formulating a number of possible cross-linguistic generalizations, and at the same time drawing some tentative conclusions concerning the nature of the associated conceptual structures. The lexical fields in question are those whose members denote gradable properties such as length, weight and temperature, within which antonymy (in the narrow sense defined by Lyons, 1963) is a major operative relation.