My “cerulean” Crayola crayon melted last summer, forsaken in my hot car, which was parked in Historic Concord Center while I attended the Annual Gathering of the Thoreau Society. All that remained were the crayon’s solidified, barely legible paper wrapper and a waxy, plain-blue stain across the edge of each page of Walden, which languished in the same plastic bag. Cerulean was my favorite Crayola in the entire box of 96 different colors. Since then I’ve resisted the temptation to buy another whole box of 96 just to get one cerulean, but my resolve continues to weaken.
According to Merriam-Webster, “cerulean” means “resembling the blue of the sky.” TrueKnowledge.com defines cerulean as “1: a light shade of blue; 2: of a deep somewhat purplish blue color similar to that of a clear October sky.” This range from light blue to deep purplish blue bothers me. It seems too broad. Also, I don’t think that every clear October sky is the same color all over the world. Other online searches turn up “azure,” “sapphire,” and “lazuline.”
Thoreau‘s Walden discusses shades of blue in the chapter called “The Ponds,” in which he vividly describes the colors of Walden Pond, the way a lover describes the eyes of his beloved in intricate detail. “Walden is blue at one time and green at another, even from the same point of view… near at hand it is of a yellowish tint next the shore where you can see the sand, then a light green, which gradually deepens to a uniform dark green in the body of the pond….Such is the color of its iris.” Later in the chapter he refers to Walden as “earth’s eye.”
As he continues describing Walden’s colors and how they appear from different vantage points, I picture Thoreau striding among the oaks and yellow pines, inhaling the fragrance of the sap, trudging through slushy spring snow, pausing to study the water from each cove, perspiring his way up a sunny hillside, traipsing over pine cones and knobby tree roots, paddling his canoe across the water’s surface.
I do these things myself. Before coming to dwell in Lincoln woods I used to drive to Walden Pond from Arlington or Cambridge, going west out Route 2. When I reached the traffic light at the junction with Route 126 and got in line for the left turn, I would always turn off the radio, turn off the air conditioning, and open the car windows. There, I was close enough to smell the pond. Making the left turn, it became possible to hear the pond. “You’re in love with this pond, aren’t you,” commented a friend in my passenger seat.
In one long sentence Thoreau captures a fleeting glimpse of an impossible blue, from the vantage point of the pond’s surface. Ever since reading this passage I’ve been striving to see what he saw:
Like the rest of our [Concord] waters, [Walden] when much agitated, in clear weather, so that the surface of the waves may reflect the sky at the right angle, or because there is more light mixed with it, it appears at a little distance of a darker blue than the sky itself; and at such a time, being on its surface, and looking with divided vision, so as to see the reflection, I have discerned a matchless and indescribable light blue, such as watered or changeable silks and sword blades suggest, more cerulean than the sky itself…
T’kheilet is Hebrew for a blue dye mentioned 50 times in the Bible to describe the color of ceremonial robes donned by the High Priest, tapestries in the Sanctuary, and ritual prayer tassels. In Biblical times t’kheilet was derived from a certain marine creature, later identified in the Talmud as“hilazon.” In the aftermath of the Romans’ destruction of the Temple in Jerusalem, in 70 CE, knowledge of the hilazon – and how to use it to produce t’kheilet – was lost. There was no more High Priest, no more Sanctuary, and the ritual tassels were made only in white.
Since then, scholars and scientists have attempted to discover the source of the original t’kheilet. In modern Hebrew t’kheilet means light blue, the color of the sky. But over the millenia some have argued that t’kheilet was “black as midnight,” “blue as the midday sky,” or even “purple.”
It all hinges on identifying the hilazon. In 1887 a Grand Rabbi researched the subject and concluded that it might have been the common cuttlefish. In 1913 another rabbi published a Ph.D. thesis concluding that the hilazon was likely a Murex trunculus snail. In 2002 an Israeli scientist proclaimed that he could produce the blue of t’kheilet using a Janthina snail. In 2008 Australian biologists announced research on creating t’kheilet using a mollusc called Australian Dogwhelk. Until someone proves conclusively which fish or snail or mollusc was the hilazon, we cannot know the color of t’kheilet.
In 1991, a non-profit organization called P’til T’kheilet (“thread of t’kheilet”) was formed in Israel to raise awareness of the color. One scholar, interviewed for the New York Times in 2011, said “T’kheilet is the color of the sky, but not the color of the sky as we know it; it’s the color of the sky at midnight. It’s when you are all alone at night that you reach out to God, and that is what t’kheilet reminds you of.”
Crayola has a crayon called “sky blue,” whose color is nothing special, completely unlike the brilliant cerulean. Instead of buying 95 extra crayons that I don’t need, maybe I’ll just wait until Crayola comes out with t’kheilet.