Philippe de La Hire, French mathematician and astronomer (b. 1640)

Philippe de La Hire, often referred to by various spellings including Lahire, La Hyre, or Phillipe de La Hire (18 March 1640 – 21 April 1718), was an extraordinary figure of the French Golden Age, a true polymath whose talents spanned an impressive array of disciplines. He distinguished himself not only as a painter and architect but also as a highly respected mathematician and astronomer. So vast was his expertise and so diverse his contributions that Bernard le Bovier de Fontenelle, the perpetual secretary of the French Academy of Sciences, famously described him as an "academy unto himself," a testament to his singular intellectual prowess and breadth of knowledge.

Early Life, Artistic Beginnings, and Parisian Return

Born in the vibrant cultural hub of Paris, Philippe de La Hire inherited a deep appreciation for the arts from his father, Laurent de La Hire, who was a distinguished and celebrated artist of his time. His mother was Marguerite Coquin. Building upon this artistic foundation, the young Philippe embarked on a significant journey in 1660, moving to Venice – then a preeminent center of European art – for four formative years to immerse himself fully in the study of painting. This period was crucial in honing his artistic skills and developing a keen eye for visual detail and composition.

Upon his return to Paris, La Hire's artistic journey took a pivotal turn. He became a dedicated disciple of Girard Desargues, a visionary French architect and geometer whose groundbreaking work in projective geometry significantly influenced the art of perspective. Under Desargues' tutelage, La Hire delved into the intricacies of geometrical perspective, a skill that elegantly bridged his artistic talents with his burgeoning scientific interests. His mastery of painting was formally recognized on 4 August 1670, when he was received as a master painter. Interestingly, his artwork has occasionally been confused with that of his son, Jean Nicolas de La Hire, who, despite being primarily a doctor, also pursued painting as a passion, highlighting a familial thread of artistic inclination.

The Ascent of a Scientist: Mathematics, Astronomy, and Cartography

Even as his artistic career flourished, Philippe de La Hire's innate curiosity drew him towards the burgeoning world of science. He displayed a remarkable aptitude for mathematics, a field in which he would eventually make profound contributions. His scientific education was significantly shaped by Honoré Fabri, a distinguished French Jesuit theologian, mathematician, physicist, and intellectual controversialist. Through Fabri, La Hire became an integral part of an influential scientific and philosophical circle. While some figures like René Descartes and Marin Mersenne had passed away earlier, their ideas and intellectual legacies continued to resonate deeply within this group. La Hire engaged with contemporaries such as Giovanni Domenico Cassini, the brilliant Italian astronomer; Claude François Milliet Dechales; the renowned Dutch polymath Christiaan Huygens and his brother Constantijn; and the universal genius Gottfried Leibniz. This diverse and intellectually stimulating environment undoubtedly fueled La Hire's multidisciplinary pursuits.

His growing reputation as a scientist led to his election as a member of the prestigious French Academy of Sciences in 1678. From this point, La Hire became increasingly active in astronomy, a field that demanded both rigorous mathematical skill and meticulous observation. He dedicated himself to calculating precise tables of the movements of the Sun, Moon, and planets, essential for navigation and timekeeping. Furthermore, he applied his inventive mind to the design of innovative contrivances specifically engineered for aiming aerial telescopes, crucial instruments for astronomical observation in an era before modern mountings.

La Hire's contributions extended beyond the celestial sphere to the meticulous mapping of the Earth. Between 1679 and 1682, he undertook extensive observations and measurements of the intricate French coastline, a vital endeavor for national security and commerce. In 1683, he played a crucial role in a monumental project to map France more accurately, assisting in the extension of the Paris meridian northward. This was a significant undertaking, contributing to the establishment of more precise geographical coordinates for the nation.

Academic Leadership and Enduring Literary Contributions

Philippe de La Hire's intellectual stature was further cemented by his appointments to prominent academic positions. In 1683, he assumed the esteemed chair of mathematics at the Collège Royal, one of France's leading educational institutions. This role allowed him to shape the minds of future generations of mathematicians. From 1687 onwards, he also lent his expertise to the Académie d’architecture, where he taught, presumably bringing his unique blend of artistic perspective and geometric rigor to architectural education.

His prolific writing career left an indelible mark on mathematics and other sciences. In 1673, he published a work on graphical methods, demonstrating his practical approach to geometry. This was followed by a seminal treatise on conic sections in 1685, a cornerstone of classical geometry that continues to be fundamental in various scientific and engineering applications. He further explored complex curves with a treatise on epicycloids in 1694, a work on roulettes in 1702, and finally, one on conchoids in 1708. Notably, his groundbreaking works on conic sections and epicycloids directly built upon the teachings of Girard Desargues, underscoring the profound and lasting influence of his early mentor, who regarded La Hire as a favorite pupil.

Beyond his original mathematical research, La Hire also contributed to the dissemination of knowledge through translation. He translated Manuel Moschopulus's essay on magic squares, a fascinating area of recreational mathematics, and meticulously compiled many previously known theorems on the subject, publishing this collection in 1705. In 1702, he released his own comprehensive set of astronomical tables, a valuable resource for navigators and astronomers of the era. La Hire's intellectual curiosity knew few bounds, as his work also ventured into descriptive zoology, detailed studies of respiration, and the intricacies of physiological optics, demonstrating his truly encyclopedic engagement with the scientific challenges of his time.

A Legacy Through Generations and Beyond the Earth

Philippe de La Hire's intellectual brilliance was, to some extent, carried forward by his descendants. Two of his sons also achieved recognition for their scientific contributions: Gabriel-Philippe de La Hire (1677–1719), who followed in his father's footsteps as a mathematician, and Jean-Nicolas de La Hire (1685–1727), who became a notable botanist, ensuring that the family name continued to be associated with scientific achievement.

As a lasting tribute to his profound and multifaceted contributions to astronomy and other sciences, a mountain on the Moon, appropriately named "Mons La Hire," stands as a perpetual monument to this extraordinary French polymath, forever etched into the celestial landscape he so meticulously studied.

Frequently Asked Questions (FAQs)

Q: What were Philippe de La Hire's primary fields of expertise?
A: Philippe de La Hire was a true polymath, active across several fields. His primary expertise lay in painting, mathematics, astronomy, and architecture.
Q: Why was he described as an "academy unto himself"?
A: Bernard le Bovier de Fontenelle used this phrase to describe Philippe de La Hire due to the extraordinary breadth and depth of his knowledge and contributions across such diverse fields as art, mathematics, astronomy, and architecture, essentially embodying the collective expertise of an entire academic institution.
Q: How did his artistic background influence his scientific work?
A: His initial training as a painter, particularly his study of geometrical perspective under Girard Desargues, provided him with a unique visual and spatial understanding. This artistic foundation proved invaluable in his work in geometry, cartography (mapping), and even the design of astronomical instruments, allowing him to visualize complex scientific problems.
Q: What were some of his key contributions to astronomy and mapping?
A: In astronomy, he was crucial in calculating precise tables for the movements of the Sun, Moon, and planets, and he designed devices for aiming aerial telescopes. In mapping, he conducted extensive surveys of the French coastline and played a significant role in extending the Paris meridian northward to create more accurate maps of France.
Q: Who were some of the influential figures in his scientific circle?
A: La Hire was part of an influential intellectual circle, particularly through Honoré Fabri. He engaged with the ideas of figures like René Descartes and Marin Mersenne, and collaborated with prominent contemporaries such as Giovanni Domenico Cassini, Christiaan Huygens, Gottfried Leibniz, and Claude François Milliet Dechales.
Q: What is the significance of the "Mons La Hire" on the Moon?
A: Mons La Hire is a mountain on the Moon that was named in his honor. This celestial feature serves as a permanent recognition of his significant contributions to astronomy and his enduring legacy in the scientific world.