The Tourbillon Chronicles:
Birth Of The Tourbillon
How a watchmaking legend created one of watchmaking’s legendary complications.
Welcome to The Tourbillon Chronicles, a four part series on one of watchmaking’s most intriguing and controversial complications.
Imagine you’re a watchmaker, and it’s the late 18th century.
This isn’t such a terrible time to be a watchmaker — in fact, if you’re interested in precision timekeeping, it’s kind of a great time to be a watchmaker. There are three great inventions that have, together, made relatively portable high precision timekeeping something practical and based on established, workable solutions. These are, you might say, the Holy Trinity of watchmaking (long before the term meant Vacheron, Patek and Audemars Piguet, because two of those brands weren’t around yet, and Vacheron was still relatively young – founded as a workshop in 1755, the company wouldn’t take on the name Vacheron & Constantin until 1819).
For all that, though, there were more than enough basic challenges in precision timekeeping to occupy the minds of the best and the brightest, one of whom was Abraham Louis Breguet, one of the most prolifically inventive horologists of all time. Although he was the creator of many beautiful and ingenious inventions, he is today best known for the tourbillon.
The tourbillon today is usually presented as an exercise in virtuoso watchmaking and visual razzle-dazzle. But it was invented by Breguet, not to romance watchmaking history, nor to amuse the eye — but rather, to solve one of the most pressing watchmaking problems of the day, and to advance the pursuit of precision.
The Origin Of Precision Timekeeping
The three critical inventions were the temperature compensated balance, the spiral balance spring and the lever escapement. The problems those inventions solved were all indispensable for the ability of watchmakers to, by the end of the 1700s, create watches that could run to a precision of a few minutes — or even a few seconds — per day. The first watches produced in the 16th century were generally relatively large devices that perhaps are better classified as portable clocks. They were vulnerable to changes in temperature, to the variation in performance of the verge escapement (the only game in town when mechanical watches and clocks began to be manufactured, the verge was very variable in its performance and had a number of disadvantages, including driving the entire gear train backward during certain phases of its operation) and the lack of a balance spring in early watches meant that the balance had no natural frequency, and so how long it took to complete an oscillation was highly dependent on how hard the escapement whacked it back and forth.
That plus the relatively primitive state of metallurgy Back In The Day meant that if you were some well heeled potentate lugging around a timepiece the size of a Thanksgiving rutabaga to show off to the other well-heeled potentates in your circle of acquaintances, you were lucky if it ran for the better part of 24 hours, and you were certainly extremely lucky if it was accurate to within an hour a day, if that.
Still, the possibility for greater precision was there. In 1759, a crabby, self-absorbed, self-taught English clockmaker named John Harrison finished his fourth attempt at making a “sea-clock” — what we today call a marine chronometer. The performance of this 13-centimeter wide device — you can call it a watch if you want, some people do, albeit it spent most of its working life resting flat and face up on a table in the ship’s cabin, rather than in a pocket — was unprecedented.
During its first sea trial in 1761, the chronometer — known today by the simple name, H4 — kept time during a crossing from England to Jamaica on HMS Deptford, so accurately that when the ship came within sight of Kingston, its calculated position was within one nautical mile of the actual position of the port. Over an 81 day voyage, after correcting for a consistent daily loss on its rate (the key word is “consistent” — as long as a chronometer is gaining or losing the same amount every day, it is by definition a precision timekeeper and can be used for practical navigation) the watch lost just five seconds — better precision than a modern quartz watch.
Small Errors Become Big Problems
The problem with H4 was that it was something of a one-off. Harrison was unquestionably a mechanical genius, but his inventions for achieving such accuracy were impossible to reproduce in quantity for large numbers of ships (by the end of the 18th century the Royal Navy had 646 vessels on the Naval List, albeit not all of them were ocean-goers). And the watch was not portable, at least not to a degree that would let any reasonable person carry it with them on a daily basis.
However, H4 did include temperature compensation for the balance spring, and also incorporated the constant force device known as a remontoir, which meant that the escapement always received a consistent amount of energy.
Over the next four decades or so after the first voyage of H4, improvements continued to be made and precision watches became smaller and slimmer. The spiral balance spring — of all the improvements to watchmaking over close to five centuries, the single most important — had been invented in the period 1650-1675, and suddenly the balance became an oscillator with a natural frequency. The temperature compensating balance went through a number of early configurations, but by 1800 the bimetallic cut balance was widely produced and would be the gold standard for precision watchmaking for more than a century. And finally, the lever escapement — invented by the English watchmaker Thomas Mudge in 1754 — offered enough consistency in action, and robustness in daily use, that it became increasingly widely adopted as well.
All this is an enormous simplification of the events that finally led to watchmakers being able to create real precision watches on a consistent basis, albeit any such watches were still hand-made, very expensive and relatively rare. They did, however, reveal new problems. If you come up with something that makes a watch more precise, you find out that things affecting precision which were unnoticeable suddenly become real issues — the effects of temperature on a watch, for instance, or variation in rate in different positions were more or less invisible against a background of an hour or more a day’s variation in rate, but add a balance spring and suddenly they leap into unpleasantly sharp focus.
One such previously concealed problem was the fact that a watch runs at different rates in different positions. There are six positions in which a watch is traditionally timed, but the biggest difference in rate is between the vertical and the horizontal positions.
Imagine a pocket watch sitting on a table, dial up. The pivots of the balance (think of them as analogous to the axle of a cartwheel) point straight up and down. The balance pivots run in ruby bearings and to keep the balance from moving up and down, there are, above and below each of the bearings, additional cap jewels (in modern watches, held in place by antishock springs, so that if a butterfingered owner drops the watch the impact on the balance pivots is reduced). Laid flat and dial up, there is almost no friction on the side of the balance pivots at all, and most of the mass of the balance rests on the tip of the bottom pivot.
Put the watch in a vertical position, and now the length of both balance pivots rest on the sides of the balance jewels. This increase in friction between the vertical and horizontal positions is the single biggest reason for the difference in rate between those positions. You can fudge this somewhat by keeping the watch vertical in your pocket during the day and laying it flat at night but this is hoping to get lucky, and of course, there’s no guarantee that the rate variations will exactly cancel out.
Breguet And The Birth Of Watchmaking’s Whirlwind
In the late 1700s, Abraham Louis Breguet put his thinking cap on and considered the problem. What he came up with is, depending on how you look at it and who you ask, either a stroke of genius or a solution in search of a problem. There is no doubt that it was a very clever piece of work and an attempt to solve the problem of positional rate variations in one blow.
A tourbillon watch has a rotating cage that contains the essential timekeeping elements — what in the business are sometimes referred to as “regulating organs.” These are the balance itself, the balance spring, and the escapement — in the case of a lever escapement watch, the lever and escape wheel. There are several ways of setting up a tourbillon but often, the cage has a gear pinion on its underside which is driven by the third wheel of the movement. As the cage rotates, the pinion of the escape wheel, which is carried on the carriage, turns against a fixed fourth wheel, also under the carriage. This drives the escape wheel, which transmits energy to the balance. Breguet would call his invention a “tourbillon” — French for “whirlwind.” Breguet was granted a patent for the invention in 1801.
Where exactly Breguet got the idea for the tourbillon is unclear, if in fact he got it from anyone or anything else at all. In watchmaking, there are very few really new ideas — as in any other field, inventions and innovations are usually based on previous attempts. The minute repeater, for instance, was preceded by hour striking clocks (among the earliest mechanical timekeepers) and then the quarter repeater, five minute repeater and finally the minute repeater proper. Even the balance spring was suggested by the earlier hog’s bristle regulator, which used flexible hog’s hair to control the oscillations of the balance.
The tourbillon, on the other hand, doesn’t have a predecessor, at least not one that I or, as far as I know, anyone else knows of. The idea may have been kicked around by Breguet and his friend and contemporary the English chronometer maker John Arnold and indeed, one of the first two tourbillons Breguet made (nol. 169) was built into an Arnold pocket chronometer movement. Still, the idea for the tourbillon seems to be completely original.
I guess if anyone was going to think of it, it was going to be Breguet. He was far from the only brilliant innovator in precision timekeeping of his day of course, but it’s hard to think of another horologist, then or since, who rivaled him in diversity as well as ingenuity. Years ago, I had a conversation with his descendant, Emmanuel Breguet, head of patrimony for Breguet, about the origin of the tourbillon and he agreed that miraculous though it seems, it was without precedent; he said, “It came from the mind of Breguet.”
Breguet sent a letter to his son in 1795 about the invention of the tourbillon, in which he wrote:
“I have succeeded in canceling out the anomalies due to the different positions of the centre of gravity and the movement of the balance wheel by distributing the friction on the different parts of the balance and the holes in which the pivots move, to ensure that the lubrication of the frictional surfaces are always the same despite the coagulation of the oil; and thus to destroy many other causes of errors which influence to a greater or lesser extent the accuracy of the movement (of the balance) and which no method has so far succeeded in eliminating except with endless fumbling, with no certainty of success.” –The Art Of Breguet, George Daniels.
The tourbillon is something we all take somewhat for granted these days in high-end watchmaking because any luxury brand worthy of the name is more or less obliged to have tourbillons in its collection. Lange, Vacheron, Patek and Audemars Piguet all have more or less traditional tourbillons in their collections and so do lots of other brands. For most of its history, though, the tourbillon was made in very small numbers and Breguet reserved them for watches made for his most distinguished (and affluent, which then as now, often amounted to the same thing for a luxury purveyor) clients, and for those especially interested in precision timekeeping. The tourbillon would be, thanks to the difficulties involved in making one, a rarity for almost two hundred years after its invention — the last word, for the watchmakers who took up the challenge, in the pursuit of the impossible goal of perfect precision.
Continue reading part 2: Two Centuries of Evolution.