The molar Kerr constants and dipole moments, measured at infinite dilution in carbon tetrachloride, of methyl, t-butyl, and ethyl iodide, and the n-alkyl iodides up to C11H23I, are recorded. Inductive effects in these molecules are briefly discussed. Estimates of the anisotropic polarisability of the C-I bond in aliphatic environments are obtained. A regular increase of anisotropy with increasing chain-branching is apparent. Molar Kerr constants of the n-alkyl iodides fall within the range +101 to 141×10 -12, and increase gradually, but irregularly, with molecular weight.