What's a mystery clock?

A gallery assistant at London's Bonhams Auction house cleans a French spelter and onyx mystery clock in preparation for a January 2011 sale.
Oli Scarff/Getty Images

Lots of people love puzzles and mysteries -- and that number apparently includes lots of clockmakers. How else would you explain the popularity of mystery clocks over the last couple of centuries? Whether they're French or German 19th-century antique curiosities worth six figures, exquisitely expensive jeweled 20th-century creations, or used models of a popular 1950s American electric clock, mystery clocks are still valued by collectors and nostalgia lovers alike.

The popularity of mystery clocks is no mystery at all. They're novelties and great conversation pieces. They are mind-boggling at first glance, and amusingly fascinating once you understand what's going on. They're triumphs of imagination and craftsmanship, and they're often works of decorative art as well.


The mystery comes in how these clocks work. They're sometimes called impossible clocks because they seem to have either no workings at all, or floaters because the clock hands don't seem to be connected to any workings. With more conventional clocks, it's easy to see where the hands are attached to the workings that move them, whether powered by a mechanical pendulum or an electric motor. But in mystery clocks, the hands seem to move with no apparent mechanism to drive them. Turn the clock over, examine the back, and you still won't be able to tell what makes it tick and keep accurate time.

So what's the answer to this mystifying puzzle? Keep reading to learn how mystery clocks work.


It's an Illusion

Mystery clocks are tricks. They're illusions and spectacles of magic, so it's no wonder that their history is entwined with that of famous magicians.

The mystery lies in the movement of the clock's hands. The creator of a mystery clock fools the observer by hiding the workings so that the hands appear to move on their own. Over the years, clever clockmakers have devised many ways to achieve this illusion. Mechanisms were closely guarded secrets -- in fact, they were often patented.


Fittingly, Jean Eugene Robert-Houdin, a 19th-century French magician and clockmaker, is widely hailed as the inventor of the mystery clock, but even his name is something of an enigma. (Houdin's last name at his birth in 1806 was Robert. Young Jean Eugene added "Houdin" to his name when he married the daughter of a prominent Paris maker of clocks and watches with that name.) Coincidentally, he had also become interested in conjuring and magic. He combined his two passions in the making of mystery clocks. His first mystery clock won a bronze medal at the Exhibition of the French Industry of 1839. Houdin used various optical tricks in his mystery clocks, including a rod that ran up through the ornate clock base and along the right of the top of the case, attaching to a screw that was connected to a second, invisible glass dial that turned behind the visible dial [source: Horologist].

In many of his mystery clocks, Houdin used some variation of secreting the mechanism the clock base and attaching the hands to a second, transparent, serrated-edge dial that was turned by pinions inside the frame of the case [source: Kolesnikov-Jessop]. Many other clock makers have used similar tricks involving transparent dials that look round but really have cogs hidden inside the clock's frame.

Keep reading to learn more about the tricks and treasures of mystery clocks.


Jewels and Figurines: The Evolution of the Mystery Clock

The mystery clock on the right is an example of a swinger.
Oli Scarff/Getty Images

Jean Eugene Robert-Houdin's success with mystery clocks inspired other clock makers. A French clock maker named Andre Romain Guilmet patented several types of mystery clocks in the 1860s and 1870s. His most famous clocks featured ornate figurines holding pendulums that swung for no apparent reason. The secret was that the figurine stood on a circular platform that moved imperceptibly, just enough to keep the pendulum moving accurately [source: British Museum].

Another man from a French clock-making family, Maurice Couet, began making mystery clocks for the famous French jeweler Cartier early in the 20th century. Cartier mystery clocks were lavishly decorated with diamonds and other jewels, and each handmade clock was set into a work of art such as a gong or miniature temple. Each had a gemstone, usually a piece of rock crystal at its center. The secret to these clocks was that the apparently solid crystal had really been expertly cut in half, and two crystal discs with serrated edges inserted. The clock hands, which appeared to float, were really attached to the discs. And the entire clock, which appeared to hang freely within the work of art, was connected to the top by invisible wires. These relatively newfangled clocks became almost instant collector's items: J.P. Morgan, the American financier, bought the first clock Couet made for Cartier. One in the shape of a temple that sold for $3,200 in 1929 sold at auction at Christie's in 1993 for more than $1.5 million [source: Blauer]. Christie's sold another Cartier mystery clock in 2009 for $530,500 [source: Kolesnikov-Jessop].


In the early decades of the 20th century, the German clock company Junghans made many ornate mystery clocks called swingers. These included such figurines as the Roman goddess Diana, the Egyptian queen Cleopatra as well as random renderings like "Onion Boy," "Barmaid," "Bat Boy, "Elephant," "Zebra" and others. You can still find these originals for sale today, as well as more modern reproductions.

The American clock company Ansonia, in Connecticut, also made figurine mystery clocks that became quite popular. Ansonia's "Gloria" clock is often used as an attention-getter in jewelry store windows. Gloria is a winged female figure holding a clock ball in her hand. The hidden clock workings are inside the ball. An Ansonia Gloria clock sold for $5,175 at an auction in 2011 [source: Kovel]. Many of the most famous mystery clocks were individually handcrafted and were made with jewels and precious metals that increased their value.

Keep reading to learn what happened when modern entrepreneurs tackled mystery clocks.


Mystery Clocks for the Masses

When electric clocks became widely available in the 20th century, enterprising clockmakers began making and selling electric mystery clocks. A Dutchman named Leendert Prins made these clocks possible in 1932 when he patented a device to move an advertisement around a clock face with no apparent mechanism. He patented a modified similar device for mystery clocks in 1941. Prins' device used four transparent discs, with the hour hand glued to one of the inner discs, and the minute hand glued to the other inner one. Electric mystery clocks were all the rage in 1950s United States. Various companies made them, including Tiffany, Rex Cole, Boots Boy and LeCoultre [source: Linz]. Most of these used the Prins device.

The most popular and famous of the electric mystery clocks was the Golden Hour made by the Jefferson Electric Co. of Illinois. It was marketed for its mystery and because the clear clock face would go with any décor. Radioactive radium paint was used on the glow-in-the-dark hands and the numbers [source: Schultz]. Jefferson sold other versions including the Golden Minute, Golden View, Golden Secret and Exciting Hour [source: Linz].


New Golden Hour clocks sold for about $25, making them affordable for ordinary people. In the second decade of the 21st century, they're prized as collectibles. You can find Jefferson mystery clocks at antique stores, clock stores or online auction sites for prices ranging from less than twice the original price to several hundred dollars. They were manufactured into the late 1980s, when the company was sold and the clock division closed [source: Russell].

The Haddon Clock Co. of Chicago made mystery clocks that looked much like the Jefferson clocks, but the Haddon clocks had hands that obviously moved. A gear was hidden in the metal ring that held the clock face, and a tiny wire on the minute hand fit into the gear. Gears attached to the minute hand drove the hour hand. The minute hand is obviously touching the rim, so the mystery was easier to solve. Other manufacturers including Mastercrafters and the English company Smith's.

In the 1980s, mystery clocks were sometimes made for special occasions or companies, such as a Faberge Mystery Clock made for the Franklin Mint, and a Lowenbrau mystery clock made by Lakeside, Ltd.

Early in the 21st century, some manufacturers such as Dior and Louis Vuitton began adapting mystery clock techniques for novelty wristwatches with transparent movements and hands that appear to float. Whether collecting curiosities or admiring expensive artworks, many people are still intrigued by mysterious timepieces.


Author's Note

I learned as much about human nature as about clocks while working on this piece. I was struck by how much people have always loved puzzles, mysteries and tricks, and how they will pay for something that's billed as amazing, impossible or futuristic.

I also found myself wanting to shop for a 1950s-era mystery clock. And I kept thinking that I had seen one somewhere in the home of some elderly relative.


Related Articles


  • Blauer, Ettagale. "Cartier's Clocks." Cigar Aficionado. July/August 1998. (June 15, 2012) http://www.cigaraficionado.com/webfeatures/show/id/Cartiers-Clocks_7402
  • The British Museum. "Mystery Clock/ Clock Case." (June 14, 2012) http://www.britishmuseum.org/research/search_the_collection_database/search_object_details.aspx?objectid=55192&partid=1&output=Terms%2F!!%2FOR%2F!!%2F23418%2F!%2F%2F!%2Fclock-case%2F!%2F%2F!!%2F%2F!!!%2F&orig=%2Fresearch%2Fsearch_the_collection_database%2Fadvanced_search.aspx&currentPage=1&numpages=10
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