PESTAB. Retention indices for ten dimethyl naphthalenes and certain other aromatic compounds are presented. These figures were obtained on open tubular glass capillary columns, wall-coated with OV-17 and with OV-275. These columns were used in conjunction with a Perkin-Elmer F33 gas chromatograph which was equipped with flame ionization detection. The carrier gas used was helium at 12 p.s.i., ca. 1 ml/min. The compounds studied included naphthalene, benzo(b) thiophene, 2-methylnaphthalene, 1-methylnaphthalene, biphenyl, diphenyl ether, 2,6-dimethyl naphthalene, 2,7-dimethyl naphthalene, 1,7-dimethyl naphthalene, diphenylmethane, 1,3-dimethyl naphthalene, 1,6-dimethyl naphthalene, 1,4-dimethyl naphthalene, 2,3-dimethyl naphthalene, 1,5-dimethyl naphthalene, 1,2-dimethyl naphthalene, 3-methylbiphenyl, 1,8-dimethyl naphthalene, acenaphthene, dibenzofuran and fluorene.