Roger Norrington is preparing to leap into the air.
"Danger here!" he shouts.
Like an airplane gaining altitude, the prominent nose tilts skyward; the hands beat the air in preparation for flight.
"Too soon!" he cries.
Up goes the monk's balding pate, the scholar's red beard, the halfback's broad shoulders.
"Swing it!" he exorts.
With a radiant look of joy creasing his face, the conductor breaks the bonds of gravity.
"Dance!" he commands.
And, as one, fourscore of London's best musicians waltz deliriously.
It was an animated diorama of 1830s concert life, a full panoply of period instruments thrillingly revived under...