Weak Interactions and Eötvös Experiments

We use a current-current model for weak interactions to show that the weak-interaction contribution to the ground state energies of typical nuclei is about a part in ${10}^8$ of their rest masses. By comparing this contribution with the results of the recent versions of the Eötvös experiments, we conclude that weak-interaction energies obey the principle of equivalence to better than a part in 100, thus refuting claims that those experiments did not test weak-interaction effects.