Two different energy-momentum tensors have been proposed to describe the electromagnetic field inside matter. Abraham suggested a symmetric tensor while Minkowski's tensor is nonsymmetric. With the aid of a thought experiment it is shown here that only the symmetric tensor satisfies the momentum conservation and center-of-mass theorems simultaneously.

• Received 15 December 1952

DOI:https://doi.org/10.1103/PhysRev.91.408