 The distinction between fundamental and derived measurement was revised by subsequent authors. Brian Ellis (1966: Ch. 5–8) distinguished among three types of measurement: fundamental, associative and derived. Fundamental measurement requires ordering and concatenation operations satisfying the same conditions specified by Campbell. Associative measurement procedures are based on a correlation of two ordering relationships, e.g., the correlation between the volume of a mercury column and its temperature. Derived measurement procedures consist in the determination of the value of a constant in a physical law. The constant may be local, as in the determination of the specific density of water from mass and volume, or universal, as in the determination of the Newtonian gravitational constant from force, mass and distance. Henry Kyburg (1984: Ch. 5–7) proposed a somewhat different threefold distinction among direct, indirect and systematic measurement, which does not completely overlap with that of  Ellis.[4]  A more radical revision of the distinction between fundamental and derived measurement was offered by R. Duncan Luce and John Tukey (1964) in their work on conjoint measurement, which will be discussed in  Section 3.4.