Buzz
In 1871, retired general Augustus J. Pleasanton addressed the Philadelphia Society for the Promotion of Agriculture, sharing his experiments with blue glass to cultivate healthier and more robust plants and animals. His theories, later published in book form in 1877, ignited a widespread fascination with the alleged scientific advantages of the color blue, leading to the phenomenon known as the “Blue-glass craze.”
The book’s lengthy title reveals the breadth of Pleasanton’s claims, suggesting that the color blue could influence everything from animal and plant growth to curing diseases in humans and livestock. He cultivated grapes and raised pigs under blue glass, believing that the blue sky in spring stimulated plant growth. This led him to patent blue-glass greenhouses.
Blue glass quickly became ubiquitous, used not only in agriculture but also in homes, hospitals, and consumer goods. By 1877, a Massachusetts company was producing 3000 square feet of blue glass daily. However, skepticism began to grow that same year. Despite the practical need for opaque containers to shield chemicals from light, the use of blue glass in medicine bottles was criticized as “persistent” and “irrational” in an 1877 reader’s letter to the Druggist’s Circular.
In the same year, the Boston Medical and Surgical Journal included a critique in its medical notes, dismissing the scientific validity of Pleasanton’s ideas. It referenced a 1712 article that highlighted a similar trend for green lights and fabrics in the 18th century. The journal added that, despite its policy against direct recommendations, it was “tempted to break its rule just once, advising hypochondriacs—always eager for new cures—to try blue pills before splurging on blue glass.”
Blue light does possess specific scientific effects, though not in the way Pleasanton claimed. Short-wavelength blue light impacts circadian rhythms, stimulating alertness—which is why using a computer at night can disrupt sleep.
Pleasanton’s legacy persists today, albeit not as he might have envisioned. In 2010, the band OK Go created an entire concept album, Of the Blue Colour of the Sky, inspired by a passage from his book. You can explore Pleasanton’s flawed yet influential argument about the color blue on The Internet Archive.
