wo centuries have passed since Ferdinand Berthoud (1727-1807) published his “Histoire de la Mesure du Temps par les horloges” (History of the Measurement of Time by Clocks), and yet it could have been written yesterday. In clear and accessible language, the first great watchmaking encyclopaedia begins by dividing the conquest of the measurement of time into nine “epochs”, the first of which is “the invention of toothed wheels”.

Their genesis is attributed to a Greek mathematician, Ctesibius (285-222 BC), who lived in Ptolemaic Egypt and perfected the clepsydra by cleverly adding gears. His contemporary Archimedes (287-212 BC) was said to have developed a “moving sphere”; a claim corroborated in 1901 when a mysterious ancient mechanism was discovered in the waters off the coast of the Greek island of Antikythera, that could predict the positions of the stars.

Over time, wheels and gears became more complex, developing into a substantial repertoire from which watchmakers could draw to make their wildest visions a reality: astronomical clocks, acoustical complications and marine chronometers. “Of all the Arts that are related to Mathematics, that of Horology is one that most excites the curiosity of the learned, for it is among the most beautiful and the most useful,” wrote master watchmaker Thiout l’Aîné (1694-1767) in 1741.

“Of all the Arts that are related to Mathematics, that of Horology is one that most excites the curiosity of the learned, for it is among the most beautiful and the most useful.”

Quo vadis, Onésiphore Pecqueur?

A watchmaker is thus as much a mathematician as he is a physicist, a chemist and, of course, a mechanic. Throughout his life, Onésiphore Pecqueur was the living proof of that. But very little is known about the circumstances of his life. He was born on a modest farm in the Amiens region of France, in the first year of the new revolutionary calendar. Legend has it that he was a precocious student, completing his horological apprenticeship in Paris in just a few months, rather than the generally required four years.

In 1818 his name appeared on the rolls of the French Academy of Sciences. While there he proposed an ingenious mechanical solution for solving any equation involving two prime numbers, including numbers greater than six figures. This clear proof of talent aroused the interest of a number of academicians. As he awaited the Academy’s final approval of his “mechanical equation”, he took part in the “Exposition des Produits de l’Industrie Française” (Exhibition of Products of French Industry) of 1819 with a clock that displayed both sidereal time and mean time. The jury, which included one Abraham-Louis Breguet (1747-1823) awarded him a silver medal for inventing a gear that “maintains both communicating movements at acceptable rates of speed”.

Although at first glance it seems banal, this discovery was to have far-reaching repercussions, well beyond the horological sphere. “By means of this artifice, the number of seconds that the sidereal clock gains or loses over sidereal time is exactly equal to the number of seconds that, at the same instant, the mean clock gains or loses over mean time.” In other words, once the clock is correctly adjusted to one time (sidereal or mean), the other time can immediately be obtained.

Basking in the recognition of his peers, the young Onésiphore, who was now running the workshops of the National Conservatory of Arts and Crafts in Paris, published a book explaining precisely how his clock worked. We have no records of how this work was received. Nevertheless, Pecqueur clearly had no intention of stopping at just one invention. It’s easy to imagine him at the Conservatoire, dreaming up new inventions and drawing inspiration from the wide array of mechanisms he restored every day. And that was why he decided to participate in the next Exposition, in 1823.

A watchmaker is as much a mathematician as he is a physicist, a chemist and, of course, a mechanic. Throughout his life, Onésiphore Pecqueur was the living proof of that.

Consecration

On 25 August 1823, the ground floor of the Palais du Louvre opened its doors to the fifth “Exposition des Produits de l’Industrie Française”. Never since the exhibition’s creation in 1798 had France seen so many industrial exhibitors, modest artisans and inventors gathered together in one place. The scale of this unprecedented event was mind-boggling: 1,762 companies, categorised by sector of activity, were accommodated in 52 rooms. Curious visitors could discover the very latest “heating and lighting” apparatus (room 13), “leathers and skins” (room 17), “musical instruments” (room 18), “silks, hosiery and millinery” (rooms 31 to 33), “jewellery, marquetry, cutlery, arms” (rooms 36 to 38) and “glassware and crystal” (room 3).

In room 35, devoted to “fine and ornamental horology”, exhibitor number 1093, the young Onésiphore Pecqueur, exhibited his wares alongside Antide Janvier (no. 1619), Lépine (no. 1574), Perrelet (no. 1598) and Rieussec. The latter presented a watch of his own invention which, the jury noted, “he calls a chronograph”. Pecqueur would have to wait until 1824 to learn the results of the exhibition. The outcome was everything he could have wished for: the jury agreed to award him the highest distinction in his category, the gold medal. His competitors had to be content with silver (the Berthoud brothers) and bronze (Rieussec).

As well as rewarding the watchmaker’s achievement, the medal also anticipated the many industrial applications that “Monsieur Pecqueur’s gears” were to have. “One can posit numerous benefits in correcting irregularities in the speed of a steam engine, a waterwheel, in distributing any resistance between two engines according to predetermined proportions; in sum, in solving a host of mechanical problems, the resolution of which is of direct interest to the industrial arts.” Pecqueur himself provided triumphant proof of this during the exhibition. He unveiled several concrete applications that connected gears to steam power, the new energy source that was to be the cornerstone of the nascent industrial revolution.

In the room devoted to “fine and ornamental horology”, the young Onésiphore Pecqueur exhibited his wares alongside Antide Janvier, Lépine, Perrelet and Rieussec.

Pecqueur, an automotive engineer before his time

On 25 April 1828, “Pecqueur gears” were back in the news once again. Pecqueur registered a patent for a brand new steam carriage, which would earn him a place in the history of the motor car. Engineer Emile Eude (18551928) would later write in his “Histoire Documentaire de la Mécanique Française” (Documentary History of French Mechanics), “What is curious about Pecqueur’s patent is the description of the differential, which proves that our modern motorists perhaps didn’t invent everything.”

In practical terms, the drive of the carriage – a steam engine installed in the front – is transmitted to the two wheels on the rear axle by a central shaft. This is connected to the shafts of the two rear wheels via a “mechanism that directs the power to each wheel without affecting their independence” according to Pecqueur’s own description. And that was to become its most influential application: when rounding a bend, the inside wheel slows down while the outer one increases its speed to compensate.

1828: Onésiphore Pecqueur devised a mechanism that regulates the driving forces by allowing both wheels on the same axle to turn at different speeds. This was the invention of the differential.

This invention, later named the “mechanical differential” is widely employed by car manufacturers even today. There are very few inventions that originate in the world of watchmaking that can claim to have had a comparable impact. Pecqueur was fully aware of this in 1828, when he registered his patent. His request was very clearly worded: “I insist most particularly on being granted the privilege of applying this mechanism to all varieties of steam carriage.” He would go on to devote the following two decades to bringing to life a multitude of steam engines, including a famous machine for making fishing nets, bought by an English company for a considerable sum.

There are very few inventions that originate in the world of watchmaking that can claim to have had a comparable impact.

The rebirth of the Pecqueur spirit

It’s one of the ironies of history (of which there are many) that the name of this genius inventor has fallen completely into oblivion. But it is about to be revived, thanks to the ambition of Patrick Bornhauser, founder and chairman of the BPM Group, which employs some 2000 staff over 110 sites, and operates in the motor vehicle distribution sector.

The great-grandson of Joachim Bornhauser, who was the official watchmaker of the Swiss town of Saint Gallen, Patrick Bornhauser has nurtured a lifelong fascination for all the disciplines that rely on the mechanical arts: fine watchmaking of course, but also cars, motorcycles, aviation and motor boats.

A descendant of a Swiss watchmaker, now at the head of a leading independent motor vehicle distribution group, Patrick Bornhauser pays tribute to the genius of Onésiphore Pecqueur through this project, which also marks the birth of a club dedicated to enthusiasts of fine mechanics.

His tribute to Pecqueur began with the creation of a GMT watch equipped with a Pecqueur differential, in a tiered construction, which will be officially unveiled alongside Watches & Wonders in March 2023.

Prototype of the future Pecqueur Motorists watch

Under the aegis of the BPM Exclusive division, this limited-edition watch will become the access code and emblem of the future “Pecqueur Motorists” club, whose motto “Mechanical Arts in Motion” perfectly captures the Pecqueur spirit. More details will be forthcoming in January 2023, with the next episode of the Pecqueur saga!

The name of this genius inventor has fallen completely into oblivion. But it is about to be revived, thanks to the ambition of Patrick Bornhauser, founder and chairman of the BPM Group.