A collector has discovered the lost personal copy of Isaac Newton from Opticks

Enlarge / Isaac Newton's personal copy of the 1717 second edition of Opticks, long considered lost, has been found. Rare Books by Peter Harrington

David DiLaura, professor emeritus at the University of Colorado, was working on his comprehensive bibliography listing all the important scientific volumes on optics when he made an unexpected discovery. The copy of Isaac Newton's seminal treatise, Opticks, which he had purchased some twenty years earlier, was found to be from Newton's personal library, which was thought to be lost for many decades. The book will go on sale at the Rare Books Fair in San Francisco, February 3-5, 2023, for $375,000.

"It's becoming increasingly rare for an author's copy of a book of this magnitude to go unnoticed for so many years," said Pom Harrington, owner of Peter Harrington Rare Books, which is handling the sale. "When DiLaura purchased this copy over 20 years ago from an English rare book dealer in West Sussex, neither buyer nor seller had any idea of ​​its history. DiLaura described his discovery as " a once-in-a-lifetime event in a collector's life," and it really is. Rare book collectors and dealers love a good story of rediscovery, especially one that has been revealed - literally in this case - from how she did it."

Newton is justifiably most famous for his Principia and the co-invention of differential calculus, but he also had a long-standing interest in optics. For example, he once stuck a long sewing needle (bodkin) into his socket between the eye and the bone and recorded the colored circles and other visual effects he saw. And as a young scientist at the University of Cambridge, he conducted what is known as his experimentum crucis, darkening his room on a sunny day and cutting a hole in the window pane to let enter a narrow ray of sunshine. bedroom. Then he placed a glass prism in the sunbeam and observed the rainbow bands of light in the color spectrum.

When he placed a second prism upside down in front of the first, the band of colors recombined into white light from the sun, proving his hypothesis that white light is made up of all the colors of the spectrum combined. Based on his theory of color, Newton concluded that refracting telescope lenses would be plagued by chromatic aberrations (the scattering of light into colors) and built the first practical reflecting telescope, using mirrors reflectors rather than lenses as a lens to solve this problem. He demonstrated his telescope to the Royal Society in 1671.

Enlarge / Engraving representing Experimentum Crucis by Isaac Newton. Getty Images

Newton was also at the center of a heated debate over whether light was a particle or a wave, a debate that had raged for millennia. Pythagoras, for example, was decidedly "pro-particle", while contemporaries ridiculed Aristotle for daring to suggest that light travels like a wave. Empirical observations of the behavior of light contradicted each other. On the one hand, light traveled in a straight line and bounced off a reflective surface. This is how particles behave. But it could also diffuse outwards and different beams of light could intersect and mix. This is wave behavior.

By the 17th century, many scientists had generally accepted the wave nature of light, but there were still holdouts in the research community, including Newton, who argued vehemently that light consisted of streams of particles which he called "corpuscles". In 1672, colleagues persuaded Ne...