sentences:  In attempting to convert the ellipses to circles of equal size MacAdam encountered the non-Euclidean nature of psychophysical color space.In the mid-1940s MacAdam pioneered the use of computers in colorimetric computations, established Hardy's reflectance spectrophotometer as a reliable industrial measuring instrument, and invented a tristimulus integrator as an accessory.With Deane B. Judd and Günter Wyszecki, MacAdam performed the first principal-component analysis of phases of daylight of various correlated color temperatures, demonstrating that they can be represented as linear combinations of a limited number of spectral components.