Electroweak effects in e+e--->e+e- at sqrt s =29 GeV.

A high-precision measurement of the differential cross section for Bhabha scattering (e/sup +/e/sup -/..-->..e/sup +/e/sup -/) is presented. The measurement was performed with the MAC detector at the PEP storage ring of the Stanford Linear Accelerator Center, at a center-of-mass energy of 29 GeV. Effects due to electroweak interference are observed and agree well with the predictions of the Glashow-Salam-Weinberg model. The agreement between the data and the electroweak prediction rules out substructure of the electron up to mass scales of 1 TeV.