Nature 438, 1083-1084 (22 December 2005) | doi:10.1038/4381083a; Published online 21 December 2005

A Titan of physics

Owen Gingerich^1

BOOK REVIEWED - Huygens: The Man Behind the Principle

by C. D. Andriesse

Cambridge University Press: 2005. 360 pp. GBP 55

Had Isaac Newton never lived, Christiaan Huygens would have iconic status for characterizing physical science in the second half of the seventeenth century. Like Newton, Huygens made enormous contributions in mathematics, mechanics and optics. He anticipated Newton in finding the formula for acceleration in the case of circular motion and brilliantly used it to determine the value of the constant of gravitational acceleration, g. He invented the pendulum clock, correctly interpreted the rings of Saturn, found the formula of the catenary curve adopted by a chain fixed at each end, and enunciated the fundamental principle of the wave motion of light.

Huygens was born in Holland in 1629, the second son of a domineering father, Constantijn, who was both a poet and a government diplomat. Christiaan's older brother, also named Constantijn, became a military officer and worked both independently and cooperatively with his younger sibling in making telescope lenses. In 1666, Christiaan, with his reputation as a mathematician already well established, went to Paris to play a leading role in the formation of Louis XIV's new Académie des Sciences. But in 1681, following the death of the minister Jean-Baptiste Colbert, whose patronage had energized the academy, Huygens was no longer welcome in France as the country turned against the Protestants.

In 1661 Huygens had visited London, meeting Robert Boyle and Robert Hooke, where he observed a transit of Mercury across the face of the Sun. In 1689, around the time of William of Orange's coronation as king of England, he again visited London, where he met Newton and Edmond Halley at a meeting of the Royal Society. There was, however, little love lost between Newton and Huygens.

Unlike Newton, who has an abundance of substantial biographies, accounts in English on the life and works of Huygens have been few and far from adequate. This biography by C. D. Andriesse, a physicist at Utrecht University, brings a wealth of newly translated information, making it the richest source of information in English about the seventeenth-century Dutch polymath. The book makes ample use of Huygens' surviving correspondence, diaries and notebooks, as well as his published volumes. Huygens was a somewhat erratic publisher, often holding back works for many years (and thus occasionally losing priority), so having access to the manuscripts was an essential part of this project.

Andriesse's book is a fascinating account, but is by no means an easy read. The flow is interrupted from time to time by technical interludes that explain, for example, Huygens' work with musical temperaments or the production of an isochronous pendulum. These require the reader to be familiar with terms such as 'tonic' or 'evolute'. However, such sections can be easily skipped by a reader impatient with these illuminating mathematical excursions.

More problematic is a torrent of proper names, both of people and geographical locations. For someone familiar with Dutch history and geography, these may pose no difficulty, but the account would have been rendered more widely accessible with a few strategically placed maps and a glossary of personal names. For instance, the first chapter, which is entitled 'Titan', ends with a paragraph concerning Huygens' discovery of the brightest satellite of Saturn, which he named Titan. Andriesse concludes by remarking that Titan is a fitting image for his subject, quoting a Latin couplet written by Huygens, translated as:

Let them remain as signs of my sagacity, and their names

That I write across the heavens be an echo to my fame.

Thereafter Andriesse often (and rather confusingly) refers to Huygens simply as Titan.

What makes the book an erratic read are the long sections from letters or diaries, filled with trivia (albeit colourful) and innuendo (regarding attractive ladies whom Huygens may or may not have taken to bed); these are interspersed with details of his mathematical or scientific achievements. My lingering impression is that the book is too uneven, and even perhaps too disturbing, to be recommended with enthusiasm.

On deeper reflection I realize that the book mirrors Huygens' own personality and psychology. Huygens was beset by painful episodes of melancholy when for many months he seems to have accomplished nothing, followed by great spurts of creative frenzy. The development of the wave theory of light, leading to the principle of the book's subtitle, occurred after a particularly devastating melancholic episode. Andriesse goes so far as to say: "It is thanks to this crisis that we have Christiaan's magnificent piece of work on light." All of this suggests to me that Huygens might well have suffered from bipolar disorder (manic-depressive illness).

Huygens was never as interested in philosophy as his contemporaries Newton or Leibnitz, but in his sixties he nevertheless managed to write a more general view of the Universe, his Cosmotheoros, and once more his scientific and instrumental genius flashed forth. He devised a way quantitatively to reduce the brilliance of sunlight to that of the star Sirius, thereby photometrically determining the distance to a typical nearby star. "What bounds of number must we set, especially if we consider the infinite Power of God!" he exclaimed. "Really, when I have been reflecting thus with myself, methought all our Arithmetick was nothing, and we are vers'd but in the very Rudiments of Numbers." It was his last great work. As the printing began, his health steadily deteriorated, possibly from cancer, and he died before the book was published, in 1695.

1. Owen Gingerich is a historian of astronomy at the Harvard-Smithsonian Center for Astrophysics and author of The Book Nobody Read: Chasing the Revolutions of Nicolaus Copernicus.