Christiaan Huygens

Dutch astronomer and mathematician

• Born: April 14, 1629
• Birthplace: The Hague, United Provinces (now in the Netherlands)
• Died: July 8, 1695
• Place of death: The Hague, United Provinces (now in the Netherlands)

Huygens was one of the greatest minds of the scientific revolution. His wave theory of light became highly influential in the nineteenth century. He discovered through his improved telescope the rings of Saturn, wrote the first formal treatise on probability, and invented the pendulum clock, which was the first truly accurate timepiece.

Early Life

Christiaan Huygens (KRIHS-tee-ahn HI-ghehnz) was born in The Hague. His father, Constantijn Huygens, was a diplomat in Dutch government service and a poet who is still better known in the Netherlands than his son. Constantijn attracted many notables to his house, among them the philosopher René Descartes. Christiaan and his brother were, until the age of sixteen, tutored at home in Latin, Greek, and the classics. In fact, all the learning available at that time was offered to them.

Christiaan studied for two years (1645-1647) at the nearby University of Leiden, where the supporters of the Aristotelian view of science were battling with the followers of the new Cartesian approach. Young Huygens joined the discussions before transferring to the new University of Breda, where Cartesianism was unopposed and the views of the Scholastics were not to be found. Huygens, after two years of study at Breda, had absorbed all the mathematical and scientific learning then available. He then went home and devoted himself for several years to advancing the frontiers of mathematics. He proved, for example, that the catenary formed by a chain hanging from two points was not a parabola, as Galileo had asserted.

In 1655, Huygens made his first extended visit to Paris. France and England were the countries where the scientific revolution was centered. Huygens’s greatest periods of achievement were to be spent in France, where his precocious publications on mathematics and his family connections afforded him entrée into the highest intellectual circles.

Life’s Work

Huygens’s first plunge into scientific research took place in 1655 and after, when he and his brother built improved telescopes, grinding their own lenses. With these instruments, the best made up to that time, Huygens found a satellite of Saturn, Titan, and discovered that Mars has a varied surface. He gradually discerned a ring around Saturn that nowhere touched the planet, thus improving on Galileo’s more primitive observation. In order to protect the priority of this discovery while continuing his viewing, he announced by the publication of a coded message that he had found the ring.

Huygens continued his work in mathematics, which he had begun in the early 1650’s with publications on hyperbolas, ellipses, and circles, and he published in 1657 the world’s first formal treatise on probability.

Seeking greater scientific precision by the more accurate measurement of time, Huygens in 1656 built a pendulum clock, his greatest original invention, and with it he inaugurated modern, accurate timekeeping. Galileo had experimented with pendulums and with escapement mechanisms but had not actually constructed a clock. Huygens described the clock in his Horologium (1658), not to be confused with his later and greater Horologium oscillatorium (1673; English translation, 1966).

Huygens was preoccupied after 1660 with attempting to use his clock to solve the problem of determining longitude at sea, as the Dutch, with the world’s largest merchant fleet, were intensely interested in navigational advances. Latitude could be ascertained easily by quadrant or sextant, but calculating longitude required an extremely accurate time measurement. Huygens had great hopes for his pendulum mechanism, and his marine clocks were given extensive sea trials but proved an ultimate failure in determining longitude. Not until well into the eighteenth century was the problem actually solved by the invention of a superbly accurate spring-driven chronometer. In an attempt to subject space as well as time to greater quantitative precision, Huygens built a micrometer in 1658. With it he could establish, within a few seconds of arc, the position of a heavenly body.

In 1661, the year he joined the Royal Society, Huygens returned to Paris, where King Louis XIV’s chief minister, Jean-Baptiste Colbert , eager to retain Huygens’s services for the French, procured for the Dutchman a significant government grant for scientific work.

Scholars interested in science had been meeting in Paris for years in the salons, or drawing rooms, of intellectuals and the wealthy. The Crown wished to formalize such gatherings, and so it founded the Académie Royale des Sciences (Royal Academy of Sciences) in 1666. Huygens’s scientific reputation was so formidable that he was made a charter member of the academy, given a regular salary larger than that of any other member, and handed the keys to an apartment in the Bibliothèque Royale. Thus, he commenced, in 1666, a period of residence in Paris lasting until 1681. Except for two extended visits home to The Hague, Huygens remained in Paris. Still, when Huygens left Paris in 1681 for a third trip to the Netherlands, he never returned. His patron Colbert died in 1683, and anti-Protestant sentiment was growing in France, making Huygens’s position difficult, as he was nominally a Calvinist.

Huygens’s philosophy of science was intermediate between those of the two giants of his day: René Descartes in France and Sir Isaac Newton in England. Huygens grew up a Cartesian but broke with his mentor over the latter’s extreme devotion to the mathematical, or deductive, approach to science. Descartes attempted to explain all phenomena by use of deductive logic alone. Newton, on the contrary, relied on observations and experiments as the bases for his laws.

Huygens’s basic approach to the universe was mechanistic, an impact or billiard ball physics, in which he denied all action at a distance. He did prefer, however, Descartes’s supposedly more tangible “vortices” of “subtle matter” to Newton’s “gravity” in explaining the movements of heavenly bodies. Gravity worked unseen and over distance, moving bodies without apparently touching them. In the matter of relativity, however, Huygens was in advance of Newton. For Huygens, all motion in the universe was relative. Huygens, in this regard, was closer to the later work of Albert Einstein.

Huygens and Newton also differed over what constituted the nature of light. Newton considered light to be composed of particles or corpuscles emitted in steady streams from a light source; Huygens regarded the transmission of such particles through empty space to be mere Newtonian “action at a distance” again and incompatible with a mechanistic view of nature. Huygens propounded a wave theory of light, maintaining that a medium, an ether, must exist in space and that light is transmitted with a rapid but finite speed as shock waves in this medium. The ether, he believed, was composed of tiny, closely spaced, elastic particles, which vibrate and pass on the waves of light. Thus he did not view light itself as a substance as did Newton, nor did he consider it to be instantaneously transmitted as did Descartes.

Huygens remained in communication with Newton, although his relations with the Royal Society dwindled after 1678. He visited England again in 1689, conversing with Newton and addressing the Royal Society on his non-Newtonian theory of gravity, a theory published the following year as Discours de la cause de la pesanteur (1690; discourse on the cause of gravity). Huygens’s last years were spent in The Hague, where he died in 1695.

Significance

Huygens would have been a great intellect in any age, but the magnitude of his brilliance was not as apparent as it might have been had he not been so close in space and time to such luminaries as Newton and Descartes. Nevertheless, his achievements were considerable.

As an astronomer he not only discovered the rings and a satellite of Saturn but also was the first to notice the nebula in the constellation Orion. In his work on centrifugal force, he was the first to theorize that Earth must be an oblate spheroid. He worked with microscopes as well as telescopes and translated some of the letters of the great Dutch microscopist Antoni van Leeuwenhoek . His work in mechanics of systems led him to invent the pendulum clock, the world’s first truly accurate timepiece.

Huygens originated the wave theory of light and thereby established the science of physical optics, although the wave theory was not accepted in his own century or the next one as the fundamental explanation of the nature of light. In the seventeenth and eighteenth centuries, Newton’s theory of the corpuscular or particulate nature of light held sway, but nineteenth century scientists focused on the diffraction of light, which can be explained only by wavelength. Thus, the ether enjoyed a renewed popularity, and in the nineteenth century Huygens’s theory was the prevailing view.

In the early twentieth century, the physics of Max Planck and Einstein led to a synthesizing of Newton’s and Huygens’s views into the quantum theory, in which both concepts were correct. Light today is considered indeed to have various wavelength properties, but it is also seen as moving in packets of energy called photons. A mathematical genius, Huygens improved on the work of Galileo in mechanics and astronomy, and he conferred and contested with the giants of his own generation. Always the pure scientist, he never dabbled in the metaphysical and was uninfluenced by religion—either the Calvinism of the Netherlands or the Catholicism of France. He died as he had lived, sure of only one thing: that there is in this universe no ultimate certainty.

Bibliography

Bell, Arthur E. Christian Huygens and the Development of Science in the Seventeenth Century. New York: Longmans, Green, 1947. This scholarly, well-written volume has long been the standard biography of Huygens in the English language. Bell gives a thorough and interesting account of Huygens’s life, his theoretical approach to science, and his actual scientific work.

Chappell, Vere, ed. Seventeenth-Century Natural Scientists. New York: Garland, 1992. A collection of essays about Huygens, Robert Boyle, and Sir Isaac Newton, describing their individual scientific contributions and the wider philosophical and intellectual world in which they worked. Also explores the influence of Descartes on their conceptions of scientific method.

Dijksterhuis, Fokko Jan. Lenses and Waves: Christiaan Huygens and the Mathematical Science of Optics in the Seventeenth Century. Dordrecht, the Netherlands: Kluwer Academic, 2004. Intended for a reader with some knowledge of physics, this work provides an overview of Huygens’s contributions to the science of optics and a broader discussion of that science during the seventeenth century.

Elzinga, Aant. On a Research Program in Early Modern Physics. New York: Humanities Press, 1972. Originally a doctoral dissertation, this work contains a lengthy chapter devoted to Huygens’s theory of research and how he broke with the system of his mentor, Descartes.

Huygens, Christiaan. The Celestial Worlds Discovered: Or, Conjectures Concerning the Inhabitants, Plants, and Productions of the Worlds in the Planets. London: Childe, 1698. Reprint. London: Cass, 1968. Short, nontechnical, and readable, this continually popular book gives excellent insight into Huygens’s thinking. He was one of the first scientists to conjecture about life on other planets.

Simmons, George Findlay. Calculus Gems: Brief Lives and Memorable Mathematics. New York: McGraw-Hill, 1992. Huygens is one of the mathematicians included in this collection of brief biographies, which discusses his mathematical theories and his relationship with Gottfried Wilhelm Leibniz, his mathematics student.

Struik, Dirk J. The Land of Stevin and Huygens: A Sketch of Science and Technology in the Dutch Republic During the Golden Century. Boston: D. Reidel, 1981. A short, illustrated volume, this book centers on Huygens as the chief claim to fame of the Netherlands in the scientific revolution of the seventeenth century. Struik not only describes Huygens’s scientific work but also shows how Huygens was influenced by technological demands and commercial pressures.

Tabak, John. Probability and Statistics: The Science of Uncertainty. New York: Facts On File, 2004. The chapter about the nature of chance includes a brief discussion of Huygens’s ideas on this subject.

Yoder, Joella G. Unrolling Time: Huygens and the Mathematization of Nature. New York: Cambridge University Press, 1988. This book describes how Huygens used mathematics to substantiate his mechanistic view of the universe. Details Huygens’s discoveries, including his invention of the pendulum clock, and describes how these discoveries are linked to his mathematical universe.