The elastic differential scattering cross sections, as well as inelastic cross sections, have been obtained for both ${\ensuremath{\pi}}^{+}$ and ${\ensuremath{\pi}}^{\ensuremath{-}}$ on ${\mathrm{He}}^{4}$ at 129, 140, and 150 $\frac{\mathrm{MeV}}{c}$, using a 50-cm helium bubble chamber. Following the suggestion of Sternheim and Hofstadter, we have analyzed these data in order to obtain the Coulomb-nuclear interference term. From this, the Coulomb amplitude is deduced, which gives information on the pion charge distribution. The data are analyzed in terms of (a) Born Coulomb amplitude containing a combined Gaussian form factor for the pion and the $\ensuremath{\alpha}$ particle, (b) pure nuclear phases, and (c) the distortion of the nuclear phases due to the long-range nature of the Coulomb field. These qualities, along with the corresponding nuclear potentials, suitably fitted to our data, are presented. We measure the rms combined radius of the pion-${\mathrm{He}}^{4}$ system as $R=1.1\ifmmode\pm\else\textpm\fi{}0.79$ F. This yields ${r}_{\ensuremath{\pi}}$, the rms radius for the pion, to be ${r}_{\ensuremath{\pi}}<0.9$ F.