  I consider infinitesimal translations $x'^{\alpha}=x^{\alpha}+\delta
x^{\alpha}$ and demand that Noether's approach gives a symmetric
electromagnetic energy-momentum tensor as it is required for gravitational
sources. This argument determines the transformations of the electromagnetic
potentials under infinitesimal translations to be $A'_{\gamma} (x') =
A_{\gamma}(x)+\partial_{\gamma} [\delta x_{\beta} A^{\beta}(x)]$, which differs
from the usually assumed invariance $A'_{\gamma} (x') = A_{\gamma}(x)$, by the
gauge transformation $\partial_{\gamma} [\delta x_{\beta} A^{\beta}(x)]$.
