The far-infrared transmission of polycrystalline C-60 and C-70 compacts has been measured from 3 to 330 cm(-1) as a function of temperature. Both intrinsic and impurity-induced absorption bands are identified in these samples. The low temperature phase of C-60 is observed to have two infrared active translational modes at 40.9 and 54.7 cm(-1). Samples of C-60 exposed to air before cooling to low temperatures contain several additional infrared bands which have been identified with adsorbed H2O vapor. A large isotope shift is observed for some of the bands when H2O is replaced by D2O, consistent with rotational or librational behavior. For C-70 one strong intrinsic band is centered at 21 cm(-1) and four much weaker bands occur at 28, 32, 52, and 64 cm(-1). When doped with H2O vapor, C-70 also produces several strong H2O impurity bands, some of which show isotopic shifts. The temperature dependence of five intramolecular C-70 modes in the frequency range from 200 to 330 cm(-1) is also reported.