Despite the careful preparation, the first Bayreuth performance of "Das Rheingold" was punctuated by several mishaps. Some scene changes were mishandled; at one point a backdrop was prematurely lifted to reveal a number of stagehands and stage machinery; early in Scene 4 Betz, as Wotan, mislaid the ring and had to go backstage to look for it; the gas lighting failed repeatedly, plunging the auditorium into darkness. Some innovations worked well – the wheeled machinery used by the Rhinemaidens to simulate swimming was successful, and the quality of the singing pleased even Wagner, who was otherwise in despair and refused to present himself to the audience despite their clamouring for him. The critics made much of the technical shortcomings, which were largely overcome during the course of the festival, although, to Wagner's fury, they failed to acknowledge this fact.