How to Catch a Photon and Measure its Mass

We examine the physical significance of a class of "table-top" experiments proposed by Franken and Ampulski as tests for a finite photon mass $\mu$. Our results stem from a theorem that in the massive-photon case the fields and currents of a system are changed only by order ${\left(\mu D\right)}^2$ from those of the massless-photon case ($D$ is the dimension of the system). This implies that the table-top method is only weakly sensitive to small "Yukawa" deviations from Coulomb's law, and so the theorem constitutes a rebuttal to the suggestion that the method can improve present limits on the photon mass. Instead it appears that Franken and Ampulski have devised a sensitive test of Faraday's Law.