The organs of colour and its impressions were but partially developed among the Greeks of the heroic age.

-- William Ewart Gladstone, Studies on Homer and the Homeric Age, 1858

Why do the Iliad and the Odyssey barely use words for color, and when they do, often confuse them, as in Homer's famous phrase "wine-dark sea"? Last week, we looked at the radical proposal first made by William Ewart Gladstone (before his four terms as Britain's Prime Minister). The ancient Greeks, he said, were essentially partially color-blind, and only in the last 3,000 years -- sparked by the invention of artificial dyes -- have we acquired the ability to distinguish a full spectrum of color.

Not just ancient Greeks. Many languages confuse, for instance, blue and green. To cite a few of literally dozens of examples: Sioux's single word for "grue" (that is, blue and green) is toto. Blue sky and green grass take the single word glas in Welsh, sheen in Kurdish and Pashto, urdin in old Basque, quin in traditional Chinese, ao in Japanese. Do these "grues" reflect a color deficiency in these people? Well, no. Language use isn't the same as sensitivity. Populations worldwide distinguish as many shades of green and blue as Europeans, even if they don't have as many "color words" as their artsy counterparts back in Paris and Berlin.

In his latest book Through the Language Glass, linguist Guy Deutscher proposes a counter-example to this apparent blue-green "confusion," inviting us to imagine a 19th century Russian anthropologist speaking to the Royal Academy of Sciences in St. Petersburg. He tells the astonished members that, on a recent visit to the British Isles, he discovered the poor natives there confuse the colors siniy and goluboy, calling them both "blue," even though they can perfectly well distinguish between the two.

Take a look at the color spectrum. Siniy, what we might call navy blue, clocks in at a wavelength of about 430 nanometers (billionths of a meter), while the wavelength of goluboy (sky blue) is about 480, for a difference of 50 nanometers. Green, on the other hand, centers around 530 nanometers. That is, the actual, measurable, range of wavelengths in the colors we collectively call blue is about the same as the difference between sky blue and green. So just as English speakers lump Russian siniy and goluboy into blue, other languages lump our blue and green into their version of "grue."

Here, surely, is the answer to Homer's "wine-dark sea." The ancient Greeks were perfectly able to distinguish between colors, just as all modern people can (at least those who aren't lacking in one or more of the three types of color-sensitive "cones" in human retinas). The fact that a language lacks words for subtle and not-so-subtle shades of color tells us nothing about the sensitivity of the speakers' eyes. Homer knew darn well what the color of the Aegean was. In fact, after a few generous cups of red wine on Ithaca's rocky shore, I bet any of us might be guilty of the same mistake. We'd call it "poetic license."

Barry Evans ([email protected]), who has enough trouble with cyan, aqua, teal and turquoise, believes grue to be a fish of another color.