Every afternoon at 2, curious visitors gather in the main gallery of the museum. They turn their backs on the Goya, the Canalettos, the Tiepolo. For them there is only one object of interest: a silver swan in a shimmering lagoon lined with 122 silver-plated leaves.
A warden greets the onlookers and introduces this rare "life-sized automaton, the finest example in the U.K." He inserts a starter handle into the base, presses a button and the bird pulses into action.
To the plinkety plonk of metallic chords, the bird looks left, peers right and swings its neck around to preen its lustrous feathers. It swings back and appears to spot fish in the running "water" at its feet. It darts down and raises its beak to display its catch, chews and swallows it. The display lasts for less than 40 seconds.
The audience smiles, laughs and applauds before making its way to the Tiepolo—or the tea room.
The scene of this miracle of clockwork machinery is the Bowes Museum in County Durham, England. Relatively unknown, the museum is as extraordinary as its star-turn.
It was built by John Bowes, a wealthy mine and land owner, to house the collection of 15,000 artworks that he and his actress wife, Joséphine, had amassed in the years between their wedding in 1852 and her death in 1874.
Instead of containing the collection in the grand home he already owned, in 1869 he started work on a museum in the style of a French château, set, improbably, in amiable countryside just outside the quintessentially English market town of Barnard Castle.
It would seem that Joséphine, whose father was a clockmaker, was an enthusiast for automata and the couple first saw—and marveled at—the swan when it was on show at the 1867 Paris International Exhibition. Bowes bought it in 1872 from a Parisian jeweler, one Monsieur Briquet, for the equivalent of $318—about $32,000 today—though its rarity makes it impossible to value, as Howard Coutts, the museum's Keeper of Ceramics and Silver, notes.
The only artifact like it is the spectacular Peacock Clock in the Hermitage, St. Petersburg, which was bought by Catherine the Great in 1781. Both were the creations of a London showman named James Cox. He worked on the swan in 1773 with the quixotic watchmaker John Joseph Merlin, who also invented wheelchairs, weighing machines and even an early roller-skate.
The two men helped satisfy the public's fascination with automata—a concept that had challenged scientists and philosophers for generations. Leonardo da Vinci drew a sketch of a robot in 1495; René Descartes (1596-1650) argued that animal parts could be replaced by man-made machinery; and few creations captured the imagination more than the so-called Defecating Duck, made by Jacques de Vaucanson in 1739, that appeared to eat grain, digest and dispel it.
Cox opened a Mechanical Museum with all sorts of moving creatures, such as an elephant with a swinging trunk, and folk flocked to see how the sophisticated use of watchmaking technology made art imitate life.
It impressed novelist Mark Twain, who visited the Paris Exhibition and wrote in "The Innocents Abroad" how the swan "had a living grace about his movement and a living intelligence in his eyes."
Needless to say, this "living grace" is underpinned by complex 18th-century technology. Most recently restored 40 years ago, there are three separate clockwork motors. One is for the music, activating steel hammers that strike out eight tinkling tunes. Another creates the illusion of the babbling brook and its darting fish. A series of camshafts, rollers and levers rotate twisted glass rods on which seven fish are attached. During the restoration it was discovered that instead of heading in the same direction, three of the fish were meant to swim forward, the rest backward. It is thought that three of the fish are from the 18th century and four from the 19th.
The most complex machinery is in the neck. The movement is driven by four springs, each about one millimeter thick. There are five levers: one operates the lower bill to preen the feathers and "eat" the fish; the second operates the fish (which is concealed in the neck) that the bird appears to catch; the third allows the swan's head to nod; the fourth arches the neck; and the fifth is linked to the middle and allows its graceful movement.
In all there are 50 parts (plus screws), including five chains of varying thicknesses that run over a series of rollers within the neck to link the parts. These chains are the originals and were made by children and young mothers whose hands were small enough for such delicate work.
The flexibility of the neck itself is ensured by a complex array of 113 rings.
Even the clear light of the gallery does little to diminish the crowd's admiration at the sheer cleverness of the swan's creators. But imagine the scene 145 years ago, when the swan would have been illuminated by candles. Imagine how it must have glowed and how, in the flickering light, the visitors to the Mechanical Museum could have thought, for a second, that this was a living creature.
In his most recent book, "Chemistry of Tears," Peter Carey has his heroine similarly bewitched by the Bowes Swan and "the huge peace of mechanical things."
He writes: "Every eerie movement was smooth as a living thing, a snake, an eel, a swan of course. As it twisted to look into one's eyes, its own stayed darkest ebony until, at that point when the sun caught the black wood, they blazed. It had no sense of touch. It had no brain. It was as glorious as God. The fish were 'sporting.' The swan bent its snakelike neck, then darted, and every single human being held its breath."—Mr. Holledge is a freelance writer based in the U.K.