WATCHMAN

Pardon me for dragging in the corpse of an adjective flogged to death by generations of book reviewers, but it can't be helped: A Case of Curiosities (Harcourt Brace Jovanovich, $19.95), Allen Kurzweil's first novel, really is brilliant. Also witty, learned, ingenious, sly, and bawdy (all picaresque novels set in the 18th century are required to be bawdy). Although it has an adolescent hero, this astonishing book isn't your standard sensitive, promising fictional debut. It reads as if it had been composed on Mount Parnassus by a committee that included Fielding, Thackeray, Voltaire, Nabokov, and Calvino. The story, which takes shape around a box of peculiar 18th-century mementos-the case of curiosities, purchased at a Paris auction-begins in 1780, in a cottage in rustic Tournay, France, where Claude Page, a boy with artistic gifts and a mole on his right hand that resembles Louis XVI, is confined with his widowed mother and two sisters during an assault by a wind known locally as the Vengeful Widow. Two visitors arrive during the storm: an irreverent abbe, ''naturalist, mechanician, philosopher, watchmaker, patriarch of the valley,'' and a sour Calvinist surgeon from nearby Geneva who has been summoned to excise Claude's mole and who in the process lops off his middle finger as well to preserve the finger for his collection of deformities. The abbe, a more benign amateur scientist, takes Claude under his eccentric wing and into his mansion, which is filled with peculiar books, servants, mechanisms, and secrets. Claude is content to exercise his budding mechanical genius perfecting one of the secrets-the erotic watches that the abbe sells to aristocrats-but when he encounters another secret (best left unrevealed here), he flees in horror. He makes his way by the usual picaresque route-a series of plucky roadside adventures-to Paris, which Kurzweil brings to crowded, raucous, shady, malodorous 18th-century life. With few prospects except starving in his garret, he becomes an apprentice to a dyspeptic bookseller who purveys pornography to aristocratic clients, and then an apprentice to one of the clients, a sex-starved married woman. But the dangerous liaison doesn't quite distract Claude from his visionary mechanical ambitions, which after a few detours culminate in his fortune-making masterpiece, a mechanical man endowed with a voice and christened the Talking Turk (who eventually loses his head in the French Revolution, an early example of art done in by ideology). Kurzweil escorts us into an era when science was haphazard, cranky, and accessible, when technology was artful and unmenacing, when people began to shape their lives in terms of their own imagination. He has filled his book with odd, telling details, oblique allusions to literary influences, and high- caliber Voltairean wit (the abbe is always denying the local Calvinists ''funds they felt predestined to receive''). As an engaging historical confection, A Case of Curiosities deserves comparison with A.S. Byatt's best- selling Possession; as an elegant, playfully intricate artifact, it deserves comparison with the watches that are Claude's, and the book's, presiding metaphor; as a synthesis of curiosity, comic tolerance, and witty exuberance, it deserves comparison with nothing less than the incomparable esprit of the 18th century itself. A

EXCERPT LOVE AND HYGIENE For the remainder of the week, Claude fretted over his appearance in ways he had never fretted before. He bathed at a local washhouse and inspected himself for lice. He tossed away his old shirt, its collar as grimy as the milling of an ancient coin, and replaced it with a nearly new chemise that Marguerite the wet nurse had cleaned with Javel water and ironed. He borrowed Etiennette's ink scraper and carved the black crescents of dirt from under his nails. Plumeaux told him, ''You are proof that infatuation is a marvelous hygienic.'' On the fateful day, Claude had only one errand to run before his trip to Madame Hugon's. A chapbook seller in a distant faubourg required two dozen copies of The Pleasures of the Aged Pervert. Claude requested and obtained coach fare. On a side street off the Place Maubert, he found an illegal vehicle lacking the double P that marked the Perreaux monopoly. He bargained for a reduced price. The business with the chapbook seller was quickly and uneventfully concluded, and Claude was soon free to pursue the patroness. With the saved fare, he stopped at a barber's to add one last gesture to the preparations. He did not need a shave-his face was smooth as a chamois rag-but he went anyway. The shop differed from its Tournay equivalent. There was no sign declaring: ''Shave for a Sou, Bleed for Two.'' Nor did the metropolitan establishment offer the service of hog and goat gelding. After asking about the presence of wens and milk scabs, the barber set upon Claude's face with special soap and a razor he boasted was made of steel forged in the Sheffield manner.