He gave a principle of conservation of energy in electrodynamics related to a force law of action-at-a-distance which, unlike that given by Coulomb, depended on velocities and accelerations.
Siya ibinigay ng isang batayan ng pag-iimbak ng enerhiya sa elektrodinamika na may kaugnayan sa isang pwersa ng batas ng action-sa-isang-layo na, hindi katulad na ibinigay ng Coulomb, depended sa velocities at accelerations.