“Considering how seldom people think of looking for sunset at all, and how seldom, if they do, they are in a position from which it can be fully seen,” it’s rare to witness an excellent one, John Ruskin argued in 1843. Evelyn Waugh saw a radiant pink sunset behind a shadow-gray Mount Etna in 1929. “Nothing I have ever seen in Art or Nature,” he wrote, “was quite so revolting.”

“You don’t need a brain to sleep” was a central takeaway for a team of biologists who found that Cassiopea, a genus of upside-down jelly­fish, display signs of sleep deprivation when disturbed by water pulses at twenty-minute intervals throughout the night.

A special committee of the U.S. House of Representatives asked Lewis W. Leeds, a ventilation engineer and prominent critic of the popular belief that night air is inherently harmful to humans, to assess air quality inside the Capitol in 1868. The resulting report concluded that the House Chamber “is really the foulest place in the whole building,” with vents “so choked up with tobacco spittal and sweepings of the floor as to render the air rising from them very disagreeable.”

Setting grim tales during nighttime was critiqued as a cliché in 1594 by Thomas Nashe. “When any poet would describe a horrible tragical accident,” he wrote, “to add the more probability and credence unto it, he dismally begins to tell how it was dark night when it was done.”

Asked whether it was night or day that first emerged when the universe came into existence, sixth-century-bc Greek philosopher Thales of Miletus replied, “Night, earlier by a day.”

Psychologists at the University of California recognized a lack of sleep “as a social repellent” and its effect contagious: “People who come in contact with a sleep-deprived individual, even through a brief one-minute interaction, feel lonelier themselves as a result.”

In September 1776, fearing illness from night air, John Adams asked Benjamin Franklin to close the window of their room in a New Jersey inn. “I believe you are not acquainted with my Theory of Colds,” Franklin responded, launching into “a harangue upon air and cold and respiration and perspiration” in favor of leaving windows open. “I was so much amused,” Adams wrote in his journal, “that I soon fell asleep and left him and his philosophy together.”

“Darkness has come upon me,” a hymn in the Rig Veda laments. “O Dawn, banish it like a debt.” The morning light is here asked, suggested translator Wendy Doniger, to act as a collection agency—to “make good what darkness had incurred or ‘exact’ the darkness from night as one would exact money.”

“The difference between us is very marked,” wrote Frederick Douglass to Harriet Tubman in 1868. “Most that I have done and suffered in the service of our cause has been in public, and I have received much encouragement at every step of the way. You, on the other hand, have labored in a private way. I have wrought in the day—you in the night.”