The analysis of trace quantities of gaseous and vapor state olefins by reaction with dimethylaminobenzaldehyde (DAB) reagent in concentrated sulfuric acid has been reported, elsewhere. Thissame reagent also reacts with liquid olefins to form similar products also having strong absorption bands in the 500 micro meter region. The liquid olefins have been studied using somewhat different reaction conditions; consequently the positions, shapes, and intensities of the absorption bands differ somewhat from those reported in the vapor phase studies. Although the work done on liquid olefins was not as extensive as in the investigation of olefin gases and vapors, the results should have applicability in the identification and analysis of small quantities of liquid olefins. (Author)