  An experimental program to demonstrate a novel phase space manipulation in
which the horizontal and longitudinal emittances of a particle beam are
exchanged has been completed at the Fermilab A0 Photoinjector. A new beamline,
consisting of a TM110 deflecting mode cavity flanked by two horizontally
dispersive doglegs has been installed. We report on the first direct
observation of transverse and longitudinal emittance exchange.
