Jean Jacques Dortous de Mayran
Who was Jean Jacques Dortous de Mayran?
French geophysicist, astronomer and most notably, chronobiologist
Biographical data adapted from Wikipedia’s article on Jean Jacques Dortous de Mayran (CC BY-SA 4.0).
Biography
Jean-Jacques d'Ortous de Mairan was a French natural philosopher, born on November 26, 1678, in Béziers, Languedoc, in southern France. He faced early personal loss, losing his father when he was four and his mother at sixteen. Despite these challenges, de Mairan pursued an education at the University of Toulouse, which set the stage for a long and successful scientific career. He lived a remarkably long life, passing away from pneumonia in Paris on February 20, 1771, at the age of ninety-two.
De Mairan had a wide range of interests in the natural sciences, including astronomy, geophysics, mathematics, and what later became known as chronobiology. He was a member of the French Academy of Sciences, one of Europe's leading scientific organizations at the time, and was also named a Fellow of the Royal Society of London and the Royal Society of Edinburgh. These honors show how well-respected he was in the international scientific community of his time.
One of de Mairan's most notable contributions came from his 1729 experiments with the Mimosa pudica plant. He observed that the plant's leaves opened and closed in a regular daily pattern, even in constant darkness without external light cues. This suggested the plant had some internal mechanism controlling its daily cycle. Although de Mairan didn't fully explore the implications, his work is now seen as a foundational experiment in the study of circadian rhythms, the biological processes that follow a roughly twenty-four-hour cycle in living organisms.
In addition to his work related to circadian rhythms, de Mairan made important observations in geophysics, such as studies of the aurora borealis and its potential connection to solar activity. He also wrote about ice, heat, and light, contributing to debates in early modern physics. His work in astronomy included observations of celestial events, and he delved into ancient texts and historical chronology, highlighting the broad cultural and scientific landscape of the French Enlightenment. He worked as secretary of the French Academy of Sciences, a position that placed him at the heart of French scientific life during a key period in its growth.
Before Fame
De Mairan grew up in southern France during the late seventeenth century, a time when natural philosophy was changing significantly across Europe. The ideas of René Descartes and Isaac Newton were altering how educated Europeans viewed the physical world. French institutions were encouraging scientific research with support from royalty. De Mairan's education at the University of Toulouse exposed him to the mathematical and philosophical teachings that would shape his future research.
After finishing his studies, de Mairan became part of French intellectual circles that valued empirical observation alongside classical learning. His early work gained attention in Paris, eventually leading to his admission to the French Academy of Sciences in 1718. This membership gave him the resources, collaborators, and publishing platforms needed to develop and share his ideas on topics ranging from planetary motion to how plants behave in darkness.
Key Achievements
- Conducted the first recorded experiment demonstrating endogenous biological rhythms in plants, founding the study of circadian biology
- Elected Fellow of the Royal Society of London and Fellow of the Royal Society of Edinburgh
- Elected to the French Academy of Sciences and served as its Permanent Secretary
- Proposed an early scientific link between the aurora borealis and solar activity
- Made significant contributions to geophysics, astronomy, and natural philosophy across a career spanning several decades
Did You Know?
- 01.De Mairan's 1729 experiment placing a Mimosa pudica plant in a dark cupboard and observing its continued daily leaf movements is considered the first recorded experiment in the science of circadian rhythms.
- 02.He lived to ninety-two years of age, an exceptional lifespan for the eighteenth century, and remained intellectually active for much of that time.
- 03.De Mairan lost both of his parents before reaching adulthood, his father at age four and his mother at age sixteen.
- 04.He served as Permanent Secretary of the French Academy of Sciences, one of the most influential administrative roles in French scientific life during the Enlightenment.
- 05.De Mairan proposed an early connection between the aurora borealis and solar emanations, anticipating later scientific understanding of the relationship between solar activity and geomagnetic phenomena.
Awards & Honors
| Award | Year | Details |
|---|---|---|
| Fellow of the Royal Society | — | — |
| Fellow of the Royal Society of Edinburgh | — | — |
| Member of the French Academy of Sciences | — | — |