Historical investigations employing spectroscopy and other optical methods frequently date from the time the instrument was first introduced into the field of analysis or physical examination. The use of optical emission spectrography in the study of ancient metals dates from 1931, when an extensive investigation on the metallurgy of central Europe was first begun. This investigation has been continued into the present. Analyses, which must be performed on a microscale, were done, and frequently still are, by observing reactions of the sample and reagents under a light microscope; chemical microscopy. As the usefulness of methods such as the electron microprobe, IR spectrophotometry, and powder x-ray diffraction techniques has become more evident, these and others have been used in the identification of pigments and other inorganic samples as well as of organic materials. Examples: 1. Investigation of Tyrian purple by electron spin resonance spectroscopy. 2. Radiographic examination of the interior construction of Chinese ceremonial bronzes, R. J. Gettens, Freer Gallery. 3. Semi-quantitative survey of the compositional variation of metal objects with x-ray fluorescent spectrography. 4. UV radiation for the identification of parchment and leather fragments, assisted by electron microscopy, chromatography and spectrophotometry. 5. The investigation of the composition of writing inks using the electron microprobe. 6. Spectroscopic methods for the analysis of pigment samples from oil or tempera paintings. Noting of the value of combining optical emission spectrography or electron microprobe analysis with x-ray diffraction and IR spectrophotometry.