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The fluorescence excitation and dispersed fluorescence spectra of jet-cooled uracil, thymine, and their derivatives have been observed. Two band systems having well-resolved vibrational structures were found for uracil and thymine in the frequency region from 31 000 to 38 000 cm"1, which corresponds to the region of the long tail in the vapor absorption spectrum. The shorter wavelength band system (system I) was identified as the 8,( , *) *-S0 transition of the diketo tautomer, while the longer wavelength system (system II) was assigned to the Si(n,ir*) *-S0 transition of one of the keto-enol tautomers. Successful detection of a very small amount of the keto-enol tautomer is due to a high fluorescence yield of the keto-enol tautomer.The nature of the ^ , *) states of the tautomers and the hydrogen-bonded complexes with water are also discussed.

The unsaponifiables from 19 vegetable oils were divided into a sterol and three other fractions by thin‐layer chromatography. All except olive and palm kernel oils gave the sterol fraction in a large quantity. Compositions of the sterol fractions were determined by gas liquid chromatography. Identification of each sterol was carried out by gas liquid chromatography and combined gas chromatograph‐mass spectrometry. Campesterol, stigmasterol and β‐sitosterol were present in all oils, and a minor amount of cholesterol in majority of the oils. Brassicasterol occurrence was widespread but its content was extremely small in oils other than rapeseed oil. Other sterols, presumably δ7‐stigmastenol and δ5‐ and δ7‐avenasterol were detected in most of the oils.

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