During the month of October, when we celebrate Halloween, it seems appropriate to examine the origin of a word that is connected to all things spectral – although we never use it in that connotation: the noun spectrum.

The name was given, describing the colors of the rainbow as seen through a prism, by scientist Isaac Newton.

Sir Isaac Newton was born on Christmas Day (depending on which calendar one uses) in 1642 in Lincolnshire, England. His father had died before Isaac was born. By the time of his birth his mother had remarried. As a result, the baby was raised by his maternal grandmother in the town of Grantham. With his familial ties a bit strained, it is not surprising that in school (a boarding school, naturally) the boy was a disinterested student with a few quirks. He boarded with an apothecary (i.e. a chemist or pharmacist) and showed an aptitude for chemical experiments. He also, at a young age, was deeply interested in clocks and other things mechanical.

His equally disinterested mother, when Isaac grew old enough for manual labor, wanted to take him from his studies to loan him to farmers to work for money – to be paid to her, of course. A professor, who had recognized Isaac’s intellect, told her the youth needed to continue his education. The same professor got Newton admitted to Cambridge University – and the world is forever grateful.

A mathematician, scientist, and genius, Isaac Newton is the one who not only gave us the Law of Gravity, he discovered Calculus and opened the way to the eventual discoveries of the Theory of Relativity and Quantum Physics (discovered by another disinterested student with a similar family life – Albert Einstein).

Isaac Newton was curious about all phenomena, and resorted to unusual tactics to delve more deeply into understanding the mechanics of them. He noticed that, sometimes, strange “ghostly” images of color appeared when pressure was applied on his eyes, or once he closed them after seeing bright lights. Because he could not trust others for exact explanations, he experimented on himself, pushing bodkins (small, round sticks with blunted ends) into the corners of his eyes – usually near the tear duct – often making them bleed. He documented his sightings of the strange apparitions of various colors that formed within his peripheral vision, after these experiments. Fortunately, the experiments did not blind him permanently – although sometimes his sight was compromised for a time.

He continued his studies, noting the different refracted colors through prisms, and after thunderstorms. When he made his conclusions, he named the organized group of colors the spectrum after the spectral images that had seemed ethereal, rather than concrete, during his many experiments.

The etymological origin of the word comes from the identical Latin word spectrum, meaning image (as in a mirrored reflection) or apparition.

Today, nearly three hundred years after his death (which occurred in 1727), we simply know the word as the colors of the spectrum, rarely connecting it with the specters of the other world.

There’s nothing ghostly nowadays about the spectrum, although it is indeed a bit eerie how the experiment to discover it took place.

Pass the word!

Sources: Newton, Sir Isaac. The Principia (originally published in 1687) and Optiks (originally published in 1704). Westfall, Richard S. Isaac Newton. Cambridge University Press, 1994.