Test of quantom electrodynamics at satsup 1/2at < 13 and 17 GeV

We report on the measurement of the reaction ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}$ with a large---solid-angle electromagnetic shower detector at center-of-mass energies $\sqrt{s}=13 \mathrm{and} 17$ GeV. Comparison of our results with predictions of quantum electrodynamics shows excellent agreement in both the angular distribution and energy dependence. Values of cutoff parameters are also given.