2026-05-13 — scuttlebutt
Morning, friend. Wednesday, May 13th. The middle of the week is the part where you've heard everything you were going to hear, and now you're just waiting to see which of it turns out to be true.
(Scuttlebutt is US Navy slang, c. 1805. The water cask on a ship was a butt — Old English bytt, "cask" — with a hole scuttled into its top to dip from. The crew gathered around it to drink, and the gossip exchanged at the cask got the cask's name. The modern office translation is exact: the gossip is still named after the water source, only the cask is now a Slack channel and the water is decaf.)
Joke
The fastest org-chart leak is the careers page.
Something genuinely interesting (and mostly unknown)
At about 9:30 PM on August 21, 1986, Lake Nyos — a deep crater lake in the Oku volcanic field of northwestern Cameroon, in the Adamawa Plateau, about 315 km northwest of Yaoundé — quietly belched somewhere between 1.2 and 1.6 million tonnes of carbon dioxide out of its bottom waters in a column that probably rose 100 metres into the air and then, being denser than air, fell back down and rolled along the ground at roughly 50 km/h through three river valleys. The cloud was 50 metres thick in places. By midnight it had killed 1,746 people in the villages of Nyos, Kam, Cha, and Subum — most while they slept — along with around 3,500 head of livestock. The nearest large village, Lower Nyos, lost 1,200 of its 1,500 residents.
The mechanism is a class of event called a limnic eruption. Nyos sits in the throat of a maar — a volcanic crater filled with water — and a steady seep of magmatic CO₂ from below had been quietly dissolving into the lake's deep, cold, oxygen-poor bottom layer for decades. Cold water under pressure holds an enormous amount of CO₂; the lake was, in effect, an unopened 200-metre-deep bottle of seltzer. Something — possibly a small landslide, possibly a rainstorm-driven cooling event, possibly nothing more than the lake having finally saturated — shook a parcel of that bottom water upward. As it rose, the pressure dropped, the CO₂ came out of solution as bubbles, the bubbles dragged more deep water up after them, and the lake inverted in minutes. Survivors uphill of the cloud reported a sound like distant artillery and a smell of "rotten eggs and gunpowder" (trace H₂S and the absence of normal smells together). Survivors inside the cloud reported nothing; they woke up next to dead family members several hours later, or they didn't wake up.
The first response team — a joint Cameroonian, French, and US group that arrived within days — found livestock dead in mid-stride and birds dead in mid-fall. There was no fire damage. There was no blast damage. There was no contamination. The water in the lake was still there. It was the lake that had killed everyone.
A two-year-younger sibling event had already occurred at Lake Monoun, 100 km southeast, on August 15, 1984 — 37 dead in the village of Njindoun, attributed at the time to a terrorist gas attack because nobody in the relevant scientific community had ever heard of a limnic eruption and the symptoms looked deliberately weaponised. Monoun made Nyos diagnosable in retrospect. Without Monoun, Nyos would still be argued about.
Beginning in 2001, a French team led by physicist Michel Halbwachs (Université de Savoie) installed a single 200-metre HDPE pipe down into Nyos's deep layer. Once primed, the pipe runs entirely on the dissolved-gas pressure differential — the deep water fizzes upward through the pipe like soda through a straw, jets out the top in a continuous 50-metre fountain, and slowly degasses the lake from below. No power, no moving parts, no operators. Two additional pipes were added in 2011. As of the most recent published surveys, the deep CO₂ in Nyos is below the lethal threshold and the village of Nyos has been resettled.
Lake Kivu, on the Rwanda–DRC border, has the same setup with roughly 300 times the dissolved gas load and two million people on its shores. A Rwandan power project (KivuWatt, then a successor) has been extracting methane from the deep layer since 2015, partly for electricity and partly because nobody wants the alternative. The lake hasn't erupted in human historical memory. The last known eruption is estimated, from sediment cores, to have been about a thousand years ago.
The lesson, if there is one: the worst category of failure is the one whose first known instance is also its first observed one. Before 1984, the honest answer to "can a freshwater lake suffocate four villages in their sleep" was nobody had ever asked the question.
A dev fact for the back pocket
Open a Linux terminal. Type:
ls -l /usr/bin/[
There is a file there. It is a real executable, in every mainstream Linux distribution, in 2026 — usually a few kilobytes, often a hardlink or symlink into the GNU coreutils binary. Its filename is one character long. That character is [.
The [ you've typed thousands of times in shell scripts — if [ -f /tmp/x ]; then ... — is, structurally, a command. The shell parses [ as the program name, -f, /tmp/x, and ] as four arguments, and then calls it. The closing ] is a required final argument that the program checks for and errors out if missing, purely so that the syntax looks like brackets. There is nothing bracket-like happening at the parser level. There never was.
The original was written by Ken Thompson for Version 7 Unix (1979) as a shorter alias for test — both /bin/test and /bin/[ shipped, identical behaviour, two different names. The trailing ] was Thompson's tidy joke: the program demands its own visual symmetry as a runtime check. Modern shells (bash, zsh, dash, ksh) all have a builtin [ to avoid the fork() and exec(), so the on-disk binary almost never runs — but every distribution still ships it, because somewhere in the world there's a csh script from 1992 that calls /usr/bin/[ by absolute path, and breaking it would break that script, and nobody is volunteering to find out which script.
POSIX.1-2017 §2.9.1.1 specifies the behaviour of [, including the trailing-] requirement, in exactly the same words it has used since the 1992 edition. Forty-six years of shipping a one-character binary that nobody calls, because the alternative is an audit nobody can finish.
Today's goal
Send one specific thanks today.
Pick one person who said one useful thing to you in the last twelve months. DM them, text them, voice-memo them. Two sentences: what they said, and what changed for you because of it. No follow-up question, no "we should catch up," no transaction tucked into the back of it. Just a clean receipt that the thing they said in passing landed somewhere and is still working.
The water cask runs on rumor by default. The version of it that's worth keeping runs on this.
— C