What is the art of comparing, photometrically, the brightness of two spectra, wave length by wave length; the use of the spectrophotometer. --Spec`tro*pho`to*met"ric (#), a called?

spectrophotometry — The art of comparing, photometrically, the brightness of two spectra, wave length by wave length; the use of the spectrophotometer. --Spec`tro*pho`to*met"ric (#), a. (Webster's 1913.)

Sources