Who Invented the Balance Spring? Reaffirming the Crucial Role of Christiaan Huygens

An article by Rob Memel, antiquarian horologist, professional certified watchmaker since 1984, and author of the book The Development Towards Huygens’ Spiral Spring (1660-1676), from which this article is a summary.

About two years ago, I embarked on an in-depth investigation into another watch-related invention by Christiaan Huygens: the spiral spring on a balance wheel. My curiosity about this subject was not only sparked by the complexity of the topic but also by the increasing amount of incorrect information I encountered in recent publications, literature, and online sources.

I noticed that especially the early history of the balance wheel and the spiral spring was often misrepresented. This issue is not unique to this particular subject. Previously, I had observed similar situations in publications about the development of the pendulum clock. It often happens that poorly substantiated claims are presented as facts, after which other authors adopt these inaccuracies. Gradually, these mistakes become part of the accepted historical narrative.

During my initial research into the balance wheel and spiral spring, I discovered that this same pattern repeated itself. Publications turned out to rely heavily on secondary sources, which were often used selectively. Many authors either lacked access to the primary documents or failed to consult them. When I contacted the authors of such works, it became evident that their conclusions did not align with the original documents. This realization served as a major impetus for me to conduct my own comprehensive research.

A second motivation for my investigation was a request to analyze Robert Hooke’s role in the development of the spiral spring. Over the past few years, several publications have appeared in England that praised Hooke’s involvement in this field. Some authors even claimed that Hooke was the true inventor of the spiral spring, thereby diminishing the contributions of Christiaan Huygens. Such claims raised questions for me: why was Hooke regarded in certain circles as the inventor, even though his scientific output and the available documents did not seem to support this assertion?

In this article, I summarize my findings. For those who seek more details, including extensive references to primary sources, I have published a book titled The Development Towards Huygens’ Spiral Spring (1660-1676). The book is available in both Dutch and English and consists of 114 pages. According to fellow historians, it is one of the most complete and accurate studies of the early history of the balance wheel and spiral spring.

The Search for Accurate Portable Timepieces

The introduction of the pendulum clock in 1657 marked a significant leap forward in the improvement of timekeeping. Pendulum clocks were substantially more accurate than earlier timepieces, which often deviated by as much as fifteen minutes or more per day. This improvement was not only important for daily life but also had major economic and nautical implications.

For seafarers, the lack of accurate portable timepieces remained a significant problem. While it was relatively easy to determine latitude at sea, determining longitude was an immense challenge. This required a highly accurate timepiece that could maintain the exact departure time, even during long voyages. Such a timepiece needed to be both precise and resilient, capable of withstanding the movements and vibrations of a ship.

The consequences of inaccurate timekeeping were often catastrophic. Ships strayed off course, collided with coasts, or were wrecked due to navigation errors. This led to the loss of lives, valuable cargo, and entire crews. As a result, the need for an accurate portable timepiece became increasingly urgent.

While Christiaan Huygens focused on developing pendulum clocks (see above) that might be suitable for use at sea, the French watchmaker Gilles Martinot took a different approach in 1660. Martinot proposed replacing the pendulum with a balance system equipped with a balance spring. This mechanism, he believed, would significantly improve the accuracy of portable timepieces.

In 1660, Martinot discussed this idea with Huygens under strict confidentiality, as noted in Huygens’ diary. However, Martinot failed to create a working model that met the desired level of accuracy. Despite his efforts, his experiments ultimately proved unsuccessful, and he abandoned his attempts after some time.

The Role of Du Son and Hooke

In 1663 and 1664, Huygens travelled extensively to Paris and London, where he established connections with prominent scientists and watchmakers. In London, he was inducted as a member of the prestigious Royal Society, where he met Robert Hooke. During these travels, it is likely that Huygens discussed his 1660 meeting with Martinot. His ideas about the balance spring probably circulated within both French and English scientific communities.

Shortly afterwards, the Frenchman Du Son and the Englishman Robert Hooke attempted to develop their own versions of a balance system with a balance spring. In 1665, both men presented their first watches equipped with a balance spring. Unfortunately, these designs were far from successful. The timepieces were inaccurate, stopped frequently and were not reliable enough to be used as timekeepers.

Despite these failures, Hooke continued his search for a solution. In 1666, he shifted his focus to timepieces that utilized magnetism. Although he devoted considerable time to these experiments, these designs also proved unsuccessful. By 1670, Hooke had abandoned his attempts altogether.

Meanwhile, a concept patent application was drafted in Hooke’s name by the Royal Society, in which Hooke claimed credit for the balance spring. However, this application was never submitted, as Hooke could not produce a working model or provide a sufficient description of his design.

The Hooke Folio

During my research, I encountered three frequently cited arguments that are often used to position Hooke as the inventor of the balance spring:

1. Hooke’s Own Claims – Hooke claimed that he had conceived the idea of a balance spring long before 1660. However, this assertion is unsupported by any evidence. Moreover, Hooke had a reputation for frequently attempting to claim the inventions of others.
2. The Patent Application – The aforementioned patent application from 1666 is often cited as proof of Hooke’s priority. However, a thorough analysis reveals that this application never progressed beyond the conceptual stage and that no working model existed.
3. The Hooke Folio – In 2006, a collection of documents was discovered in an English country house. This book, known as the Hooke Folio, contained previously lost minutes of the Royal Society. Among these, the minutes dated June 23, 1670, mention a timepiece by Hooke. Some historians interpreted this as evidence of Hooke’s role in developing the balance spring. However, a careful analysis shows that the entry does not refer to a balance spring, and its significance for the history of the balance spring has been greatly overstated.

Christiaan Huygens and the Spiral Spring

While others failed in their attempts to improve portable timepieces, Huygens achieved great success through his scientific approach. Between 1673 and 1674, he conducted extensive research into the vibrations of strings in musical instruments. He discovered that strings behave as harmonic oscillators. This insight inspired him to apply the principles of harmonic oscillation to a balance wheel with a spiral spring.

On January 20, 1675, Huygens recorded his first Eureka moment: the invention of the spiral spring on the balance wheel. Just three days later, he designed an improved model, known as the double balance, which further enhanced accuracy and stability. Huygens published his findings on February 25, 1675, in the Journal des Sçavans, the world’s first scientific journal. He was granted patents for his invention in both France and the Netherlands.

Despite receiving recognition, Huygens faced opposition from others who claimed credit for the invention. The French watchmakers Isaac Thuret and Jean de Hautefeuille, as well as Robert Hooke, disputed Huygens’ priority. Ultimately, Huygens was recognized as the rightful inventor in France and the Netherlands while the matter remained unresolved in England.

In 1675, both Huygens and Hooke produced watches (not clocks) featuring a “spring,” but their approaches were vastly different. Huygens initially collaborated with Isaac Thuret, but the partnership was short-lived due to Thuret’s false claim of inventing the spiral spring. Shortly thereafter, Huygens began working with the Parisian watchmaker Antoine Gaudron. Under Gaudron’s craftsmanship, watches incorporating Huygens’ innovative spiral spring were produced.

By the end of 1675, Huygens and Thuret reconciled, and their collaboration resumed. From that point on, Huygens relied on Thuret’s services once again. All the watches commissioned by Huygens featured his spiral spring. Furthermore, Huygens generously shared his invention with other watchmakers in Paris, enabling them to benefit from this technological advancement. This led to a rapid increase in the production of watches with spiral springs, significantly improving the accuracy and reliability of portable timepieces.

Meanwhile, Hooke also began producing watches in 1675 but refused to adopt Huygens’ spiral spring. Instead, he attempted to develop his own systems, which were less successful. Hooke collaborated with Thomas Tompion, one of the most skilled watchmakers of the time. However, their partnership was far from smooth. Hooke’s fiery temperament and tendency toward confrontation frequently caused tension between him and Tompion.

By 1676, it had become clear that Huygens’ spiral spring was the preferred choice among watchmakers and users. The superior performance of watches with a spiral spring quickly established them as the standard. This preference endured not only in the following years but even across centuries. Huygens’ invention laid the foundation for the modern mechanical watch industry and cemented his status as one of the greatest scientists and inventors of his era.

Conclusion: Christiaan Huygens’ Legacy

The concept of using a balance wheel with a spring was first introduced by Gilles Martinot in 1660. However, his experiments were unsuccessful, and subsequent attempts by Du Son and Hooke also failed. Moreover, Hooke provided no concrete evidence to support his supposed priority.

Christiaan Huygens succeeded whereas others failed. He applied scientific principles and experimental rigour to develop an entirely new concept: the spiral spring. This invention was revolutionary and remains the foundation of modern mechanical timekeeping. Without a doubt, Huygens is the rightful inventor of the spiral spring.

ISBN 978-90-835149-0-1: The Development Towards Huygens’ Spiral Spring (1660-1676)©
ISBN 978-90-835149-1-8: De ontwikkeling naar Huygens’ spiraalveer (1660-1676)©

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This article is released in the frame of an exhibition held at the Musée International d’Horlogerie (MIH), dedicated to the beating heart of the mechanical watch, as 2025 marks the 350th anniversary of the publication of Christiaan Huygens’ design for the regulating balance-spring. Named “Innovation in Movement”, the exhibition presented by the MIH and the Dutch foundation Stichting Haegsche Tijd, explores the origins, developments, and various applications of this invention. It highlights how the balance-spring laid the foundations of modern watchmaking and became a strategic component of the watch industry. The exhibition will be held from 21 February – 22 June 2025 at the MIH.