Finding Indigo: An Adventure in Pharmacology
As history would have it, in the mid-1660s, a young Isaac Newton shone a light through a prism and set out to delineate the colors of the visible spectrum. He added one color—indigo—in order to balance the colors and make them an even seven. Since then, modern scientists have stopped recognizing it as a separate division, but that didn’t stop a young Oliver Sacks from searching for it.
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Photo courtesy of Parl.