Résumé : The reaction K+p → Δ++(1236) + anything is studied at beam momentum 8.2 GeV/c. The spin density matrix of the Δ++ shows than one-pion exchange is dominant at low-momentum transfer. The total and topological K+π- cross sections have been determined by a Chew-Low extrapolation in the cm energy range from threshold to 1.8 GeV, using three different methods of extrapolation. © 1975.