Style: Now that's what he calls music: Where on earth does Radio 3 get its strange ethnic music? From the tiny office of the producer, John Thonrnley, reports John Windsor

John Thornley, BBC Radio 3's producer of ethnic music programmes, saw no crocodiles as he waded chest-deep through a flooded estuary on his way to Nukukaisi village on Makira, one of the tiny Solomon islands in the Pacific. His lorry had forded two rivers but this was too deep. Presumably, no crocodiles saw him, either. But news of a man having been snapped up by one that week hastened him to the opposite bank, clutching his tape recorder.

Entering the Polynesian chief's stylish house of branches and leaves, he followed advice to approach him on all fours. The chief was not completely mollified. He glanced at his Swiss wristwatch and told him: 'I thought you said you were coming at eight o'clock.'

No one dares stand taller than a seated Polynesian paramount chief. But Mr Thornley discovered that the job of sticking a microphone 6ft up a wooden house post can be accomplished without breach of etiquette: by symbolically casting down one's head and reaching up with both arms to fix it with gaffer tape.

The two hit it off, as the BBC's unique recordings of Makira warrior songs prove. The chief was pleased to accept Mr Thornley's gift of a postcard of the Houses of Parliament taken from the south bank of the Thames. 'How often does it flood?' he asked. Later, Mr Thornley had the presence of mind to take his leave not only crawling but bottom first, unlike his Melanesian guides. He alone was told he would be welcomed back.

I chanced upon Mr Thornley, a previous acquaintance, on the steps of the BBC's Langham Street studios, as he was going in to work on his regular Friday programme (that week, Latvian folk songs).

Having entered his tiny realm on the second floor without so much as a genuflection, I watched him snap an audiotape into a massive player and was startled by a piercing, resonant wail. 'The Papua New Guinea friction drum,' he announced proudly. 'Thought to be extinct. The Livitu villagers of New Ireland broke the taboo by playing it for me. It should be heard only when someone dies.'

Shaped like an oversized shoe last, the friction drum is a solid piece of polished wood with no resonant cavity but a space between two of its sections. It is oiled with leaves and rubbed with the palm of the hand, producing a sound by the same principle as a finger rubbed round the rim of a wine glass. A bull roarer - a long piece of string with a wooden blade on the end - accompanies it, being whirled round to produce 'a ghastly fluttering sound to signify the soul passing out of the body'.

Mr Thornley uses a network of globetrotters, mostly academics, to help bring back the strange sounds with which he ruffles Britain's airwaves. One of them, the ethno-musicologist Colin Huehns, whose PhD thesis was on the music of North Pakistan, has just left on a British Academy fellowship to record sounds from the surrounding areas: Afghanistan, Kashmir, Chinese Xinjiang and Tajikistan - to be broadcast this winter in a Radio 3 series on the traditional music of the Silk Road. Among his previous prize discoveries: a Hunza valley reed band that strikes up every time a goal is scored at polo and the same area's flute bands, which have taken to playing eccentric variants of British marching tunes.

Carol Tingey, a former London University student, has learned a dialect of the Kathmandu valley which she tramps through in search of its music and culture, with both her recording equipment and her baby strapped to her back.

Some ethnic sounds are available nearer home. Mr Thornley discovered the Chinese Guo brothers in Covent Garden, busking arrangements of folk tunes on flutes and a sheng - a mouth organ with a bundle of pipes: 'A brilliant sound and played with enormous virtuosity.' They recorded two concerts for Radio 3. Meanwhile, busking somewhere on the London Underground is a South American harpist Mr Thornley hopes to catch up with.

An opera conductor in Germany and an assistant to the musical director of the National Theatre in Mannheim before he joined the BBC in 1984, Mr Thornley says: 'At first, I felt ill at ease at not being a professional ethno-musicologist. I thought, 'Sooner or later people are going to find me out'. Now, I feel I've left very little music out.

'Ethno-musicologists may have knowledge of the music of two or three countries but not five continents. It's hard for them to get funding for anything other than specialised projects: if you asked for a grant to study the music of the world, or even, say, North or South America, no one would take you seriously.' His tour of Papua New Guinea was funded by the Commonwealth Trust.

With his broad experience, he takes the world of musical sound very seriously - especially its impact upon physiology. Although new-born babies are more receptive to sound than to sight, particularly the voice, the use of music to produce specific effects in others appears to survive into adulthood only in folk cultures. Even lullabies have been forgotten in industrialised countries, where today's audiotapes of technologically generated 'pink noise', to send babies to sleep, are considered a breakthrough.

The ancient world seems to have known better. The texts of the Indian Veda credit Lord Krishna with using music to promote the well-being of both people and crops - a tradition kept alive as Gandharva Veda, which is increasingly appreciated by Western concert-goers.

Mr Thornley's ears have quivered to more exotic sounds. In the mosquito-infested upper Sepik river area of Papua New Guinea the cults of the Aiwa tribe are devoted to the cure by music of 'man em i gat sik' (pidgin for 'man who is sick'). 'It's a wonderful yodelling, overtone sound: very powerful. The overtones penetrate the nervous system like a mantra. I'm convinced there's something in it.'

The singing relatives, gathered round the sick man with their shields bearing clan symbols, also prepare a concoction of cassowary (a large, flightless bird) cooked inside a banana mixture. A little indigestible for a sick man, Mr Thornley suggested. Not at all, he was assured: it's the relatives who eat it.

'Whenever you hear a falsetto voice,' he said, 'it indicates that magic is being invoked for a beneficial effect or to counteract spells. Wicked spells tend to sound a bit dreary.'

There is a solo falsetto used to catch sharks off the coast of New Ireland and a high-pitched crooning used by groups of New Hanover adolescent boys to attract the girls of their choice. They sometimes hold a lock of the loved one's hair. Both singers and instruments go through initiations. The slit drums of Kar Kar island are made deep in the jungle by men who observe celibacy and beat their drums at full moon. The slit drum's message, borne by a sort of Morse code of boom-booms, can be heard 20 miles away: 'Big chief is dead: tell other villages'; 'Come to a party'; or 'Wife come home, I'm hungry'.

The Baining people of volcanic New Britain bring rain, paradoxically, by means of a fire song and dance, performed with arms entwined with snakes. The singers' tongues flicker continuously like flames. Unlike most of the tribal music of Papua New Guinea, the voices and drums keep strictly to the hair-raisingly rapid tempo.

Does it work? 'Every time we've played it at Broadcasting House,' said Mr Thornley, 'it's started to rain.'

(Photograph omitted)