The gyromagnetic ratios g of the 122-kev state of Sm/sup 152/ of the 123- kev state of Gd/sup 154/, and of the 89-kev state of Gd/sup 156/ have been measured to be 0.35 plus or minus 0.03, 0.367 plus or minus 0.03, and 0.32 plus or minus 0.03, respectively, by the precession of the angular correlation of gamma-ray cascades proceeding through these states in an external magnetic field. The perturbations of the angular correlations for sources both in aqueous solution and in molten anhydrous chlorides have been studied. The attenuation in a transverse magnetic field was used to determine the hyperfine structure constant of the 89-kev state of Gd/sup 156/ in the /sup 8/S/sub 7/2/ ground state o f Gd/sup 3+/ in aqueous solution as a = 17 plus or minus 3 Mc/sec. The perturbations in molten Gd sources were found to be much weaker than in solution and to be unaffected by magnetic fields. (auth)