Urine was so valuable in ancient Rome that there was a toilet tax

From the Journal of Urology: "First century Rome saw the introduction of vectigal urinae, a tax introduced by Roman emperor Vespasian for the collection and distribution of urine, an expensive raw commodity. It was used in the tanning industry, where it was mixed with the hide to soften it, loosen the hairs and dissolve the fat. It was also used as bleach where tunics were immersed in urine and whitened. Wealthy Romans were willing to pay large sums of money for toothpaste in which urine was the key ingredient. It was thought that Roman urine would not be effective but rather Portuguese urine provided an ideal whitening effect, and so large quantities of the ‘stronger' Portuguese urine were imported for this purpose. It is said that when Vespasian's son Titus protested against the vectigal urinae, his father held up a gold coin and said “It doesn't smell!” To this date, Vespasian's name is associated to public urinals in France (vespasiennes), Italy (vespasiani), and Romania (vespasiene)."

In 1935 the US Army bombed a Hawaiian volcano to stop the lava flow. But did it?

From the USGS: "The eruption in question began on November 21, 1935. Six days later, an unusual breakout at an elevation of 8,500 feet on the north flank of Mauna Loa sent lava to the north. On December 23, fearing that the flow would reach the headwaters of the Wailuku River, which supplied water for the town of Hilo, Thomas Jaggar, founder of the Hawaiian Volcano Observatory, called on the Army Air Service to bomb the lava flow source. His hope was that the lava tubes or channels could be destroyed, thereby robbing the advancing flow while feeding another flow that would re-cover the same area. The flow was bombed on December 27, and lava stopped flowing during the night or early morning of January 2, 1936. Jaggar publicly praised the Army for its responsiveness and technical accuracy in delivering the bombs to his selected targets. In turn, Jaggar was praised for his successful experiment and saving Hilo. But at least one scientist questioned the effectiveness of the bombing."

Hemingway and his wife Martha both wrote about D-Day and Mrs. Hemingway did it better

From Chris Daly: "Martha Gellhorn, then 35, was the third wife (of four) to Ernest Hemingway, then 44. During their years together, from the first meeting in late 1936 until their divorce in late 1945, the two writers were not only lovers (sort of). But they were also literary rivals. There was one occasion when they both covered essentially the same story at essentially the same time – the invasion of Normandy. In the research for my book, I was struck by how different their approaches were and by how superior the work turned in by Gellhorn was. Hemingway was mostly avoiding covering the war – he stayed home in Havana, where he often started with a Scotch around 10 a.m. and ended the night by sleeping in his clothes. Gellhorn got accredited as a war correspondent and headed to Italy – the fifth war she covered, after Spain, the Sudetenland, Finland, and China."

Hi everyone! Mathew Ingram here. I am able to continue writing this newsletter in part because of your financial help and support, which you can do either through my Patreon or by upgrading your subscription to a monthly contribution. I enjoy gathering all of these links and sharing them with you, but it does take time, and your support makes it possible for me to do that. I also write a weekly newsletter of technology analysis called The Torment Nexus.

It's called laughing gas but a growing number of Americans are dying from it

From the BBC: "Meg Caldwell's death wasn't inevitable. The horse rider from Florida had started using nitrous oxide recreationally in university eight years ago. But like many young people, she started to use more heavily during the pandemic. The youngest of four sisters, her use continued to escalate, to the point that her addiction started ruining her life. She temporarily lost use of her legs after an overdose, which also rendered her incontinent, but she continued to use, buying it in local smoke shops, inhaling it in the car park and then heading straight back into the shop to buy more. She sometimes spent hundreds of dollars a day. She died last November, in one of those car parks just outside a vape shop. The number of deaths attributed to nitrous oxide poisonings rose by more than 110% between 2019 and 2023,according to the Center for Disease Control."

A pond in Antarctica is so salty it never freezes even at -50 but scientists don't know why

From Wikipedia: "Don Juan Pond is a small and very shallow hypersaline lake in the western end of Wright Valley, Antarctica. It is wedged between the Asgard Range to the south and the Dais Range to the north. With a salinity level of 45.8%, Don Juan Pond is the saltiest of the Antarctic lakes, and this salinity causes significant freezing-point depression, allowing the pond to remain liquid even at temperatures as low as −50 °C (−58 °F). Don Juan Pond was discovered in 1961. It was named for two helicopter pilots, Lt. Don Roe and Lt. John Hickey, who piloted the helicopter involved with the first field party investigating the pond. Its extreme salinity has been the subject of extensive research, with multiple competing or complementary mechanisms proposed. The precise origin of the salt content in the pond also remains a topic of ongoing investigation."

The mating dance of the male peacock spider

Acknowledgements: I find a lot of these links myself, but I also get some from other newsletters that I rely on as "serendipity engines," such as The Morning News from Rosecrans Baldwin and Andrew Womack, Jodi Ettenberg's Curious About Everything, Dan Lewis's Now I Know, Robert Cottrell and Caroline Crampton's The Browser, Clive Thompson's Linkfest, Noah Brier and Colin Nagy's Why Is This Interesting, Maria Popova's The Marginalian, Sheehan Quirke AKA The Cultural Tutor, the Smithsonian magazine, and JSTOR Daily. If you come across something interesting that you think should be included here, please feel free to email me at mathew @ mathewingram dot com