Stress fields at the earth's surface and the consequent strain fields require a harmonic description which contains both spheroidal and toroidal components. The elastic response of the earth to spheroidal stresses is completely described by well-known Love numbers, and it is shown here that the Love number concept lends itself to the description of the forced toroidal response as well. The toroidal Love number of degree 1 is shown to bear on problems which involve a change in the rotation of the earth just as the spheroidal Love numbers of degree 1 are related to translations of the earth. Thus the effects of mantle elasticity on wind-induced changes in the length of day are embodied in the degree 1 toroidal Love number. These effects are found to be below the level of detectability for all but the largest amplitude fluctuations of short period.