Now Madame Gioconda proposed to win her way back at stilettopoint.

Mangon watched her impassively as she ranted on nastily in a cloud of purple cigarette smoke, a large seedy witch. The phenobarbitone was making her drowsy and her threats and ultimatums were becoming disjointed.

‘…memoirs too, don’t forget, Hector. Frank exposure, no holds barred. I mean… damn, have to get a ghost. Hotel de Paris at Monte, lots of pictures. Oh yes, I kept the photographs.’ She grubbed about on the couch, came up with a crumpled soap coupon and a supermarket pay slip. ‘Wait till those lawyers see them. Hector—’ Suddenly she broke off, stared glassily at Mangon and sagged back.

Mangon waited until she was finally asleep, stood up and peered closely at her. She looked forlorn and desperate. He watched her reverently for a moment, then tiptoed to the rheostat mounted on the control panel behind the couch, damped down the lamp at Madame Gioconda’s feet and left the stage.

He sealed the auditorium doors behind him, made his way down to the foyer and stepped out, sad but at the same time oddly exhilarated, into the cool midnight air. At last he accepted that he would have to act swiftly if he was to save Madame Gioconda.

Two

Driving his sound truck into the city shortly after nine the next morning, Mangon decided to postpone his first call the weird Neo-Corbusier Episcopalian Oratory sandwiched among the office blocks in the downtown financial sector and instead turned west on Mainway and across the park towards the white-faced apartment batteries which reared up above the trees and lakes along the north side.

The Oratory was a difficult and laborious job that would take him three hours of concentrated effort. The Dean had recently imported some rare thirteenth-century pediments from the Church of St Francis at Assisi, beautiful sonic matrices rich with seven centuries of Gregorian chant, overlaid by the timeless tolling of the Angelus. Mounted into the altar they emanated an atmosphere resonant with litany and devotion, a mellow, deeply textured hymn that silently evoked the most sublime images of prayer and meditation.

But at 50,000 dollars each they also represented a terrifying hazard to the clumsy sound-sweep. Only two years earlier the entire north transept of Rheims Cathedral, rose window intact, purchased for a record 1,000,000 dollars and re-erected in the new Cathedral of St Joseph at San Diego, had been drained of its priceless heritage of tonal inlays by a squad of illiterate sound-sweeps who had misread their instructions and accidentally swept the wrong wall.

Even the most conscientious sound-sweep was limited by his skill, and Mangon, with his auditory super-sensitivity, was greatly in demand for his ability to sweep selectively, draining from the walls of the Oratory all extraneous and discordant noises — coughing, crying, the clatter of coins and mumble of prayer — leaving behind the chorales and liturgical chants which enhanced their devotional overtones. His skill alone would lengthen the life of the Assisi pediments by twenty years; without him they would soon become contaminated by the miscellaneous traffic of the congregation. Consequently he had no fears that the Dean would complain if he failed to appear as usual that morning.

Halfway along the north side of the park he swung off into the forecourt of a huge forty-storey apartment block, a glittering white cliff ribbed by jutting balconies. Most of the apartments were Superlux duplexes occupied by showbusiness people. No one was about, but as Mangon entered the hallway, sonovac in one hand, the marble walls and columns buzzed softly with the echoing chatter of guests leaving parties four or five hours earlier.

In the elevator the residues were clearer — confident male tones, the sharp wheedling of querulous wives, soft negatives of amatory blondes, punctuated by countless repetitions of ‘dahling’. Mangon ignored the echoes, which were almost inaudible, a dim insect hum. He grinned to himself as he rode up to the penthouse apartment; if Madame Gioconda had known his destination she would have strangled him on the spot.

Ray Alto, doyen of the ultrasonic composers and the man more than any other responsible for Madame Gioconda’s decline, was one of Mangon’s regular calls. Usually Mangon swept his apartment once a week, calling at three in the afternoon. Today, however, he wanted to make sure of finding Alto before he left for Video City, where he was a director of programme music.

The houseboy let him in. He crossed the hall and made his way down the black glass staircase into the sunken lounge. Wide studio windows revealed an elegant panorama of park and mid-town skyscrapers.

A white-slacked young man sitting on one of the long slab sofas — Paul Merrill, Alto’s arranger — waved him back.

‘Mangon, hold on to your dive breaks. I’m really on reheat this morning.’ He twirled the ultrasonic trumpet he was playing, a tangle of stops and valves from which half a dozen leads trailed off across the cushions to a cathode tube and tone generator at the other end of the sofa.

Mangon sat down quietly and Merrill clamped the mouthpiece to his lips. Watching the ray tube intently, where he could check the shape of the ultrasonic notes, he launched into a brisk allegretto sequence, then quickened and flicked out a series of brilliant arpeggios, stripping off high P and Q notes that danced across the cathode screen like frantic eels, fantastic glissandos that raced up twenty octaves in as many seconds, each note distinct and symmetrically exact, tripping off the tone generator in turn so that escalators of electronic chords interweaved the original scale, a multichannel melodic stream that crowded the cathode screen with exquisite, flickering patterns. The whole thing was inaudible, but the air around Mangon felt vibrant and accelerated, charged with gaiety and sparkle, and he applauded generously when Merrill threw off a final dashing riff.

‘Flight of the Bumble Bee,’ Merrill told him. He tossed the trumpet aside and switched off the cathode tube. He lay back and savoured the glistening air for a moment. ‘Well, how are things?’

Just then the door from one of the bedrooms opened and Ray Alto appeared, a tall, thoughtful man of about forty, with thinning blonde hair, wearing pale sunglasses over cool eyes.

‘Hello, Mangon,’ he said, running a hand over Mangon’s head. ‘You’re early today. Full programme?’ Mangon nodded. ‘Don’t let it get you down.’ Alto picked a dictaphone off one of the end tables, carried it over to an armchair. ‘Noise, noise, noise — the greatest single disease-vector of civilization. The whole world’s rotting with it, yet all they can afford is a few people like Mangon fooling around with sonovacs. It’s hard to believe that only a few years ago people completely failed to realize that sound left any residues.’

‘Are we any better?’ Merrill asked. ‘This month’s Transonics claims that eventually unswept sonic resonances will build up to a critical point where they’ll literally start shaking buildings apart. The entire city will come down like Jericho.’

‘Babel,’ Alto corrected. ‘Okay, now, let’s shut up. We’ll be gone soon, Mangon. Buy him a dnink, would you, Paul.’

Merrill brought Mangon a coke from the bar, then wandered off. Alto flipped on the dictaphone, began to speak steadily into it. ‘Memo 7: Betty, when does the copyright on Stravinsky lapse? Memo 8: Betty, file melody for projected nocturne: L, L sharp, BB, Y flat, Q, VT, L, L sharp. Memo 9: Paul, the bottom three octaves of the ultratuba are within the audible spectrum of the canine ear — congrats on that SP of the Anvil Chorus last night; about three million dogs thought the roof had fallen in on them. Memo 10: Betty — ‘ He broke off, put down the microphone. ‘Mangon, you look worried.’