Meanwhile, this enchanting collection of songs for voice and orchestra - setting the sort of ancient Chinese texts which have become home territory for Weir - is interesting because it demonstrates a distinctive personality adapting to circumstance and adopting the sound equivalent of broader brush strokes in its method. Weir's music, typically, is clean cut, wry, quietly subversive, with a teasing playfulness. And the tease, as often as not, involves a trick of scale that confines big ideas in the wrappings of small ones - almost in the way the artist Christo wraps tower blocks like Christmas parcels.
Natural History was originally commissioned for an American orchestra (the Boston Symphony) and an American singer (Dawn Upshaw). The result is an American-sounding piece, with all the core ingredients of Weir but relocated to the land of Samuel Barber and John Adams where the tease is whether the writing will steer toward romanticism (as it threatens) or to minimalism (ditto). There's also, I think, a complete reversal of that trick of scale. Instead of squeezing big into small, the music inflates small into big - which may be why it sounds too easy. Even by Weir's stardards, what you hear is lean. It offers little in the way of flesh-and-blood events.
But I liked the piece: its charm, invention and disburdened grace. And this Proms performance, for which Dawn Upshaw joined the BBC Philharmonic under Mark Elder, made an eloquent centrepiece in a programme largely devoted to musical whimsy - starting with Stravinsky's Circus Polka (as written for Barnum & Bailey's performing elephants) and ending with Richard Strauss's overblown orchestral portrait of his life at home with Mrs Strauss, Symphonia Domestica.
The BBC Phil was back at the Proms the following night with a different conductor, Vassily Sinaisky, and a very different programme of Russian music inspired by the stories of Pushkin, whose 200th anniversary falls this year. So much Russian music derives from Pushkin that this concert could easily have run on for a fortnight. But it settled for a token pot- pourri of Glinka, Rimsky-Korsakov and Tchaikovsky, with a rare performance of Rachmaninov's one-act opera Aleko to follow.
Rachmaninov wrote this score as an official student exercise when he was 19. And for a 19-year-old it's pretty remarkable, with a developed sense of orchestral colour in the dances and the assured vocal writing of the one big number for the central character. But otherwise it feels like a pale and stilted revisitation of Carmen (decent guy loves faithless gypsy, kills her, curtain) with unfulfilled leanings toward the verismo shock tactics of Cavalleria Rusticana. The problem is that it's hard to shock when your chorus reacts to a double murder with a textbook fugue. This Proms performance made the best of things with strong, impassioned soloists Elena Prokina, Vasilly Gerello and Vsevolod Grivnov, and orchestral playing of such eloquence that you could almost believe it.
One of the week's other Proms composers was William Walton, whose profile has been riding high since Opera North dusted down Troilus and Cressida and OUP started reissuing his work in new editions. He has just been Composer of the Week on Radio 3. He was the subject of a recent TV documentary. And if you saw that film, you'll remember the footage of Ischia in the Bay of Naples, where he went to live and bathe his later works in Mediterranean warmth. Susana Walton, the composer's widow, lives there still, in the amazing paradise-domaine of terraced gardens, waterfalls and fountains that the Waltons built from scratch. And in that paradise, for the past 10 years, the Walton Trust has run a unique series of opera masterclasses for student singers. For three weeks they work - under some of the most eminent tutors in the business - on a specific opera which is then performed in public. This year it was Ormindo, the Cavalli opera which launched the revival of interest in that composer's work when Raymond Leppard's realisation of the score played at Glyndebourne in the 1960s. And it was the same Leppard edition that was heard at Ischia - sounding fancifully risque in these days of stricter period sensibilities. In any case, the point of the Ischia masterclasses is process rather than product.
This year's process was administered by Colin Graham, once the leading light of opera staging in the UK but no longer; he now lives in the US where they appreciate him more than we do. Watching the painstaking detail he programmes into every piece of business, every gesture and response, you can understand why critics think him old fashioned: an exponent of the how-to-hold-a-fan-and-lift-a-crinoline school of opera. But his sense of the importance of minutiae is illuminating, and more useful to young singers without stagecraft than the random do-as-you-feel approach of an experimentalist.
Under Graham the Ischia students learn to make their gestures meaningful: to move for a purpose, or not at all; to treat each vocal entry as a reaction to something done or said, and not merely the place in the score where it's My Turn To Sing. Above all, they learnt how to give physical expression to a deeper, more complete reading of character. In Graham's words, it's about acknowledging responsibility - to the piece, the audience, and the other singers on the stage. And though this year's singers at Ischia were a mixed-ability bunch that didn't say too much for consistent standards in auditioning, there was a striking vocal performance from a Japanese mezzo, Kachi Sanae; a brazen drag act (oh yes, they had drag in 17th-century Venetian opera) from British tenor Matthew Marriott; and one peformance of superlative, all-round accomplishment from a British mezzo, Donna Bateman, whose beguiling voice and manner guarantee that we'll be hearing more from her. Note the name.