You don’t have to know a lot about physics to be excited by these thirty-one Queries. The more you know about what has happened in physics since 1704 (the year that Newton, at the age of sixty-two, published the Opticks), the more exciting it becomes to read the book. If you are lucky, the hair will rise on the back of your neck and you will walk down the street whistling in admiration of the mind of this man who knew so much so long ago.
Newton was not right in all of his ideas. His major error—indicated in Queries 27 through 29—was in believing he had proved (or in believing that it would some day be proved) that rays of light are very small bodies emitted from shining substances. He proposed, in other words, and placed all of his scientific credit on, the corpuscular theory of light, and opposed with all his strength the wave theory that was being put forward during Newton’s time by the Dutch experimenter and mathematician Huygens. In fact, we have finally decided we know that both theories are correct, depending on circumstances: light sometimes behaves like a wave, sometimes like a stream of particles. We could not do physics today without these hypotheses about the nature of light, and we have agreed to ignore what seems like a contradiction. Newton, unfortunately, could not ignore it. Neither could Huygens.
Christiaan Huygens was born in 1629, some thirteen years before Newton, into a very eminent Dutch family at The Hague. He showed the extreme precocity typical of great mathematicians and was internationally famous by the age of twenty-five. He invented the pendulum clock, built larger and better telescopes than ever before, and produced a nearly perfect eyepiece still known by his name. He published his Treatise on Light in 1690, although the researches on which it is based had been done ten or a dozen years before—not long after Newton’s work, which he had also failed to publish for some years.
Huygens’s book is remarkable in its strict insistence on a wave theory of light and its brilliant success in explaining the observed phenomena of refraction and reflection with the use of the theory. In addition, Huygens included a long description of his experiments with Iceland spar, a strange crystal that produces a double refraction of the light that passes through it. Newton thought that Huygens had not explained these optical phenomena in Iceland spar by means of wave theory—the theory that light is propagated through an ethereal medium in waves instead of in corpuscular form—and Huygens thought Newton’s corpuscular theory could not explain them. It is curious, in fact, that they were both wrong on a major point that escaped each of them.
Both Newton and Huygens believed there must be an ether—enormously more rarefied than air, as Newton insisted—either to support the propagation of waves or to transmit the effects of force acting at a distance (gravity, for instance). Scientists searched for evidence of this ether for two centuries; it was not until the 1880s that the theory of an ether was finally disproved. This would have been incomprehensible to Newton and Huygens, who would have asked, If there are light waves, then what are the waves in? Indeed, it is a good question, an adequate answer to which requires some very fancy partial differential equations.
Newton and Huygens, who died in 1695, are not “just for scientists.” These two works on optics are readable by and important for nonscientists. Do not let their titles, the few diagrams, or the mention of axioms, definitions, and theorems discourage you. These books document and reveal the great journey of the modern mind, from Galileo to Einstein, from Newton to Planck and Heisenberg, Fermi and Bardeen. They are beautiful and moving books, clear as all good books should be, mind-expanding as only the greatest books are.
JOHN DRYDEN
1631–1700
Selected Works
John Dryden was born in 1631 and educated at Trinity College, Cambridge. He inherited a small estate but he soon decided he wanted to be a writer and nothing else, and in fact he may have been the first professional writer in the sense that he supported himself entirely by writing (of course with help from time to time from noble patrons). He never stopped writing until his death in 1700 and therefore had a long career in which he wrote many works: numerous plays, satirical writings, literary criticism, and a few occasional poems, several of which are good. See especially “To the Memory of Mr. John Oldham” and “A Song for Saint Cecelia’s Day,” which he composed near the end of his life and close to the end of the seventeenth century. Dryden, a Catholic, here pays tribute to one of his most loved muses, St. Cecelia, patron saint of music. Another is a song from “The Secular Masque,” which he wrote in 1700, the year of his death. It pulls no punches about the age then coming an end:
All, all of a piece throughout:
Thy chase had a beast in view;
Thy wars brought nothing about;
Thy lovers were all untrue. ‘
' Tis well an old age is out,
And time to begin a new.
A professional writer in the seventeenth century needed to publish translations to keep his head above water. Dryden’s large achievements in this field include works by Theocritus, Horace, Homer, Juvenal, Ovid, Boccaccio, and Chaucer. His major translation was Virgil’s Aeneid, and I think it is the best rendering in couplets of this work, fully comparable to Pope’s Iliad (also in couplets).
My favorite work of Dryden’s is his prose essay, “Of Dramatick Poesie,” which he wrote in 1668. It has at least two things to recommend it. First, it is probably the earliest serious study of the work of Shakespeare in English. This paragraph (which I quote only in part) is deservedly famous:
He [Shakespeare] was the man who of all modern poets, and perhaps ancient poets, had the largest and most comprehensive soul. All the images of Nature were still (i.e., always) present to him, and he drew them, not laboriously, but luckily (i.e., easily); when he describes anything, you more than see it, you feel it too. Those who accuse him to have wanted learning, give him the greater commendation: he was naturally learned; he needed not the spectacle of books to read Nature; he looked inwards, and found her there.
That is very good criticism, and it is also written in what is close to being modern English. (In a sense, Dryden almost invented modern English.) As compared to the prose of Milton, for example, or other seventeenth-century prose stylists, it is clarity itself.