Typical watches can be of fruits, animals, or almost anything at all

At the end of the 17th century, another invention changed the course of watchmaking: the balance spring, which helps regulate the mechanism and improves the accuracy of time display. “Watches can keep time to within minutes a day,” said Mr. Ball. “Everyone was taken with a clock that could be used to tell the time and mark your day. Shape clocks kept coming, in the form of a parrot, a turkey, a chimera or a fantastic bird, rabbits, dolphins, dogs, lions, tulips, sea urchins, pigeons and more.”

Miranda Maracini, a librarian at the Horological Society of New York, writes in an email that improvements in enamelling and engraving techniques at the end of the 18th and beginning of the 19th centuries “allowed artisans to create highly realistic, detailed clocks shaped like fruits, animals, and objects like hats and baskets. Many clocks also connected to other interests of the period—hot air balloons, for example.”

She wrote: “My favorite watch is a small early 19th century revolver. It is only a few inches long and covered in pearls and enamel. It has a secret part in the handle that opens to reveal a small hour dial. Pulling the trigger releases a red enamelled flower bud from the end of the revolver, which in turn wafts perfume from its center.”

Technological developments beyond watchmaking have affected the look of watches as well. “From 1850,” said Mr. Ball, “you get another change, the introduction of the railways. Time matters. Games were not so much fun for people as clocks that kept the best possible timing.”

“There aren’t many surviving clocks from the 1850s onwards that you can call real clocks,” he said. “The next time they appear, from 1900 onwards, they are effectively as jewellery,” says Bulgari’s Serpenti.

For Luc Van Cauwenbergh, a Brussels-based watch collector, “Model clocks are pieces of art and testify to the goldsmiths’ boundless creativity in form and decoration.”