Wagnerian Covariance
The Czech tenor Leo Slezak had just finished singing his "Farewell"
in "Lohengrin". He walked towards the boat drawn by a swan but the
backstage staff made it move away too fast and he was unable to
board it. Slezak strolled towards the audience and with a wonderful
presence of mind asked: "Tell me, please, what time is the next swan?"