Thoughts

The mathematician Edward Kasner asked his young nephew, Milton Sirotta, to name a 1 followed by a hundred zeros, and the boy said googol. Then he offered a bigger one, the googolplex: a 1 followed by as many zeros as you could write before you got tired. Kasner kept the name and threw out the definition, and his reason, as he and James Newman told it in their 1940 book, was a fair one: different people get tired at different times, and it would never do for a prizefighter to own a larger number than a mathematician just because he had more stamina. So the googolplex became a 1 followed by a googol zeros, which is far more than anyone could write. The boy’s number was not so much too vague as too small, and the fair fix turned out to be one that wears out everybody equally.

Goodbye is what is left of “God be with ye.” The Oxford dictionary’s earliest example of the squeezed-down version comes from a letter Gabriel Harvey wrote in 1573, and the long form and the short one lived side by side until about 1800. The “God” probably turned into “good” because of the company the word kept: good day, good night, good morrow, all of them said at the door. Once people stopped hearing the blessing inside it, the phrase lined up with its neighbours and took their shape. Nobody decided that, and nobody had to. The meaning wore off, and the word stayed in the one place it was always for, the moment someone goes where you can’t follow.

In 1788 James Watt fitted his steam engines with a flyball governor, borrowed from the windmills: two iron balls on hinged arms, spun by the engine itself. Run too fast and the balls swing outward, and a linkage closes the steam valve; slow down and they drop, and it opens again. The engine minds its own speed. Except that sometimes, as engines got better, the cure set up a wobble of its own: the valve corrected a little late, the engine overshot, the governor corrected back, and the speed swung up and down around the point it was meant to hold. In 1868 James Clerk Maxwell wrote a paper, On Governors, working out with mathematics when a device built to steady a machine would make it swing instead. Hardly anyone read it for eighty years. Then in 1948 Norbert Wiener named a new science of feedback after it, cybernetics, from the Greek for steersman, partly in honour of Maxwell, because governor comes from the same Greek word by way of Latin. So the whole field takes its name from a machine whose most useful lesson was that correcting things is not the same as steadying them.

On New Year’s Day 1739 a French captain, Jean-Baptiste Bouvet, saw land through fog in the far South Atlantic and took it for a cape of the great southern continent everyone expected to find. He wrote down where it was, and the position was wrong. Thirty-odd years later James Cook sailed to the spot, found open sea, and decided Bouvet had probably mistaken an iceberg for land. Which was a fair conclusion, and also wrong. In 1808 a whaler came across the island, sailed all the way round it and gave it his own name. It is still there, mostly under ice, about as far from anywhere as an island gets. What I like is that both mistakes were careful ones: Bouvet saw something real and put it in the wrong place, and Cook looked in exactly the right place for something that had never been there.

The typo in a message is nearly always easier to see a second after you send it. Before that, you were reading what you meant, which is a very forgiving text: your eye slides straight over “teh” because you know perfectly well what goes there. Pressing send changes your job. You stop being the person who wrote it and become, for the first time, somebody reading it, with no say over what it says, which is exactly the reader the typo was waiting for. Careful people get the same effect by leaving a draft overnight, or reading it aloud, or going through it backwards. But the cheapest way anyone has found to read your own words like a stranger is to make them impossible to change. It is probably the only proofreading method that works every time, and it only works too late.

John Harrison, the man who eventually solved longitude at sea with a clock, started out as a carpenter, and his first clocks were made mostly of wood. That sounds like a beginner’s compromise, but it took him somewhere. The oils of his day were the weak point of any clock: they thickened in the cold, thinned in the heat and slowly went gummy, and a clock is only as steady as the friction inside it. So instead of hunting for a better oil, Harrison kept finding ways to need less of it, with parts made of lignum vitae, a tropical wood so resinous it greases itself, and later with movements designed to run on almost none at all. A turret clock he built in the early 1720s for the stables at Brocklesby Park, in Lincolnshire, is reported to be still going. The usual move, when one part of a machine keeps failing, is to make that part better. His was to keep asking whether the machine had to have it.

In 1956 the psychologist George Miller published a paper that began with a complaint: he had been persecuted by an integer. The number seven kept turning up in his experiments, roughly how many tones or loudnesses people could tell apart, and roughly how many digits they could hold in mind at once. The title called it the magical number seven, plus or minus two, and that is the part everyone kept. What the paper went on to say was more careful. Memory, he argued, is limited not by how much information it holds but by how many chunks, so a person who groups digits cleverly can hold far more than seven. And at the end he looked at all the sevens he had gathered, the seas and the wonders and the days of the week among them, and said he suspected it was only a pernicious, Pythagorean coincidence. Later work puts the limit nearer four. So the most famous number in psychology was announced by a man who doubted it, in a paper whose real finding was that the number depends on what you count, and it went out into the world as seven anyway, because a joke in a title travels further than a hedge in a conclusion.

Horace Walpole made up the word serendipity in a letter to a friend in January 1754, and explained it with a fairy tale he had once read, The Three Princes of Serendip. The princes, he wrote, were always making discoveries, by accidents and sagacity, of things they were not in quest of. Then he gave his example. One of them worked out that a mule blind in its right eye had lately walked the same road, because the grass had been eaten only on the left side. That is not an accident. That is a man looking at a verge and reading it. Walpole’s one illustration of happy chance is a piece of detective work, and the only luck in it is that the mule happened to go that way. The word has spent more than two and a half centuries meaning the accident. The other half of the definition, the part that notices which side of the road is chewed, was there in the first letter, and it was the half doing the work.

Peter Durand patented the tin can in England in 1810, and for decades nobody sold a tool to open one. People used what they had: a knife, a bayonet, and by one account the advice was to cut round the top with a chisel and hammer. The first real can openers came in the 1850s, Robert Yeates’s in England in 1855 and Ezra Warner’s in America in 1858, nearly half a century late. It is easy to make a joke of that, but the delay probably wasn’t stupidity. The early cans were thick, made to survive ships and campaigns, and nothing small opens a thick can. An opener only made sense once cans got thinner, and they could only get thinner once people trusted them. The opener couldn’t come first. It had to wait for the can to stop being built against everything, including the person who bought it.

In the 1960s, digging at Masada, archaeologists found date seeds about two thousand years old, and put them away. Some sat in a university drawer for around forty years until, in 2005, a researcher planted three, mostly to see. One came up. They called it Methuselah, and it grew into a healthy palm of a kind not seen in that country for centuries. It also turned out to be male, which for a date palm means that on its own it would never bear a single date. So other old seeds were coaxed out of the ground, and one of them, a female grown from a seed found in a cave not far off, was given its pollen. A few years ago she fruited. The first fruit of the palm that started it all came off somebody else’s branches. Two thousand years in the ground and forty in a drawer, and what it was waiting for in the end was not water or light but another seed that had waited about as long.

For a while the axolotl was filed as its own kind of animal: a salamander that kept its feathery gills, lived in the water all its life, and bred that way. Then, in Paris in the 1860s, among the axolotls being raised from a handful brought over from Mexico, a few did something none of the others had. Their gills shrank, their fins went, and they climbed out as land salamanders that looked very like the American tiger salamander. The animal everyone had been describing was a larva. It had simply never needed to finish. Later it turned out that the change hangs on thyroid hormone, and that a dose of it can push an axolotl through a metamorphosis its ancestors in the lakes around Mexico City had mostly stopped bothering with. What I like is that the grown-up form was never lost, only left unused, the way you might keep the key to a house you moved out of years ago. Most axolotls live their whole lives without trying the door.

Gibraltar is joined to Spain by a flat strip of sand, and during the Second World War the runway was laid straight across it, because that was the only flat ground there was. Which meant the main road into Gibraltar ran across the runway. For about eighty years, when a plane was due, barriers came down like a level crossing and the traffic waited while an airliner went past where the cars had just been. In March 2023 a road tunnel, about 350 metres long, opened under the end of the runway, and the cars stopped crossing. People on foot and on bicycles still do. So if you walk in from the border, you can still be asked to stand at a barrier and wait while somebody else arrives.

Hand someone a new pen to try and there is a good chance they write their name. Not a word, not the date: the name, or else a tight little spiral. It makes sense once you see it as a test. To find out whether a pen is any good you need to write something whose shape you already know exactly, so that any skip or blot or wobble can only be the pen’s fault. You have probably written your name more often than anything else. You know how it goes down to the angle of the last stroke. So the name is a ruler, and you lay the pen against it to see where the pen comes up short. Signatures drift over a lifetime, of course. But for the length of one scribble on the back of a receipt, yours is the fixed point, and the rest of the world is the thing being checked.

Alfred Wegener said the continents move, and for evidence of it happening now he had longitudes. Expeditions had fixed positions on the coast of Greenland across the nineteenth century, and when he set the old numbers side by side the island seemed to be sliding west by something like thirty metres a year. In the 1930s Danish surveyors measured again with better instruments and found the shift was mostly error in the old observations, which were never as exact as he had trusted them to be. The real drift, it turned out decades later, is a couple of centimetres a year, more than a thousand times smaller. So the one measurement he had of the thing moving was wrong, and the thing was moving. He was right about the earth and wrong about his proof, and he died on the Greenland ice in November 1930, before anyone had settled either half.

In 1494 Luca Pacioli, in a fat Venetian book of arithmetic for merchants, gave a rule for how long money takes to double: divide 72 by the rate of interest. At six percent, twelve years. He did not say why it worked, which is usually taken to mean it was already old. Nobody could have said why. The reason sits in the natural logarithm of 2, and logarithms were not published until 1614, a hundred and twenty years after the book. The honest number is nearer 69, but 69 divides by almost nothing, and 72 splits cleanly by 2, 3, 4, 6, 8, 9 and 12, and at the sort of rates merchants actually charged it happens to land closer to the truth anyway. So the rule was picked for being easy to do in your head, and turned out more accurate because of who would be using it. It worked for more than a century before anyone could explain it, and it has never needed the explanation to keep working.

Nostalgia was coined in 1688 as the name of a disease. A young doctor, Johannes Hofer, wanted a learned word for what the Swiss called Heimweh, and he built one out of Greek: nostos, the return home, and algos, pain. The symptoms listed for it included fever, an irregular heartbeat, weakness, stomach pain and melancholy, and it was said that in some cases it could kill. Military doctors went on diagnosing it long after Hofer. Somewhere along the way the word left medicine and changed sign, and now it is something we choose on purpose: an old song, a sweet they have started making again, a film set in the year we were twelve. Nobody runs a fever from it. What strikes me is that the illness was always about a place, a valley you could in principle walk back to. The kind we kept is mostly about a time, which has no road back to it. The disease, at least, had somewhere to go. What we kept is the version with nowhere to go, and we decided to enjoy it.

In 1854, at the Crystal Palace exhibition in New York, Elisha Otis rode a platform up an open shaft, and when it was well off the ground he had the rope that held it cut. The platform stayed where it was. Lifts already existed. What Otis had built was a way for them not to fall: a steel wagon spring above the platform, kept bent by the pull of the hoisting rope, with ratchet teeth along the guide rails on either side. While the rope pulls, the spring stays bent and clear of the teeth. When the rope goes slack, the spring snaps straight and catches them. Nobody has to notice that anything has gone wrong, and nothing has to switch on. The part that stops the lift is pushing to stop it the whole time, and the rope is all that holds it back. The machine doesn’t need to be told to stop. It needs to be allowed, every second it moves, to keep going.

The ginkgo seems to have outlived whatever animal it grew its seeds for. The fleshy coat smells of rot, the way fruit meant for a scavenger might, and the creature that once ate it and carried the stone away is gone, perhaps a very long time ago. People took over the job. They ate the kernels, planted the trees by houses and temples across China, Japan and Korea, and for a while Western botanists thought gardens were the only place ginkgo still grew. (Wild stands may survive in remote parts of southwest China. Whether monks saved the species is a nicer story than the evidence supports.) Now the ginkgo is a favourite street tree, because it shrugs off smog, and many cities plant only males, often cuttings from one male tree, so that nothing falls on the pavement. A female sold by mistake can take fifteen or twenty years to give herself away. So the tree that lost its partner found a new one, and the new one has kept it alive in cities around the world on one condition: that it stop doing the thing the partner was for.

When the first platypus skin reached England at the end of the eighteenth century, George Shaw of the British Museum, who described it in 1799, took a pair of scissors to it. He was looking for stitches. A duck’s bill sewn onto the body of some small furred animal was exactly the kind of thing a traveller might sell a naturalist, and he wanted to find the seam before anyone else did. There was no seam. More skins came, none of them had seams either, and the animal had to be admitted to exist. It took most of another century to settle that it also lays eggs. Shaw was right that something had been stitched together. He was looking for the join in the animal, and it was in the list of what a mammal was allowed to be.

In the Karakum desert in Turkmenistan there is a crater about seventy metres across that has been on fire for as long as most people can remember, and nobody can say for certain when it was lit. The usual story is that Soviet drillers broke into a pocket of gas in 1971, the ground fell in under the rig, and someone set the gas alight so it would burn off in a few days. Some Turkmen geologists say the collapse came in the 1960s and the fire not until the 1980s. The records that would settle it are missing, classified, or simply not where anyone has looked. It is being put out now, and not with water. The state gas company has drilled new wells around it to draw the gas away and sell it, and in 2025 it said the flames were about a third of what they had been two years before. So the fire with no reliable first day may yet get a last one, and it will be written down, because by then the gas will be worth counting.

Nobody carries all the shopping in from the car in one trip to save time. A second trip takes perhaps a minute. The one trip takes longer than that once you count the stop at the front door, where you stand with four bags cutting into each hand and try to work the key with the hand that is also holding the milk, and then with an elbow, and then, briefly, with your teeth. The minute you saved is spent there, with interest, and the eggs are the deposit. What the one trip buys is not time. It is a small verdict. Going back would mean the load was more than you could carry, and the point of the whole performance, staged on an empty driveway for an audience of nobody, is to find out that it wasn’t.

Mary Anning spent her life on the beach at Lyme Regis in Dorset, digging fossils out of the crumbling cliffs and selling them, and some of what she dug out changed what people believed about the deep past: ichthyosaurs, the first nearly complete plesiosaur. The papers that described those animals to the learned societies often left her out. The first scientific account of an ichthyosaur she had excavated does not mention her at all, and later ones thanked the gentlemen who had bought the bones from her. A few writers did name her. Today most people meet her through she sells seashells on the seashore, and there is no evidence the tongue twister was ever about her. She was left off the pages that were about her, and written into the one line that wasn’t.

In 1897 the Indiana House of Representatives voted 67 to 0 for a bill which, among several ways of squaring the circle that did not agree with each other, made pi come out as 3.2. Its author, a physician named Edwin Goodwin, offered the state the use of his discovery without paying royalties. In the House the bill went first to the committee on swamp lands. In the Senate it went to the committee on temperance, which recommended it. What stopped it was chance. A Purdue mathematics professor, Clarence Waldo, happened to be at the statehouse that week on other business, heard the bill being discussed, and explained to some senators what was wrong with it. Even then no one voted it down: the Senate postponed it indefinitely. So no senator is on record voting against a wrong value of pi. The record shows only a room that decided it would rather not be asked.

Salary comes from the Latin salarium, and salarium comes from sal, salt. That much is solid. The story that usually comes with it, that Roman soldiers were paid in salt, is not: no ancient source says so, and the documents that use the word show a fixed payment made to officials of a certain rank in the time of Augustus. It may once have been money for buying salt, or it may have been named for something else to do with salt that nobody wrote down. What the word kept was the salt, and what it lost was the reason. People cannot leave a gap like that alone, so they fill it with the most vivid thing that would fit: a legionary holding out his hands for a fistful of white crystals at the end of the month. The story is not evidence for the word. The word is the only evidence for the story.

In 1775 Alexander Cumming, a Scottish watchmaker, patented a flushing toilet, and the part of it that mattered most did not move at all. He bent the waste pipe into an S. Water settles in the low curve of the bend and stays there, and that small pool is the whole wall between the house and the sewer: the smell cannot climb through it. Each flush sweeps the bowl clear and leaves fresh water standing in the bend for next time, so the machine’s most important work is done by the little it fails to get rid of. A man who spent his working life on moving parts is remembered for a thing that works by staying still.

The tumbleweed that rolls down the empty street at the start of a western is most often Russian thistle, and it is not from the West. It was first recorded in North America in Bon Homme County, in what was then Dakota Territory, in the 1870s, its seeds most likely mixed into flaxseed brought over from the Russian Empire and sown by farmers who only wanted flax. (One historian is sure it was already in Kansas by then; either way, it came in a sack.) When the plant dries in autumn it snaps off at the base and rolls, shaking out seed as it goes, and within a few decades it was all over the West. So when the films needed a plant to say this place is empty and nobody has settled here, the one they chose had come in with the settlers, hidden in what they meant to plant.

No monarch butterfly makes the round trip. The ones that leave the eastern United States and Canada in autumn, bound for a few mountains in central Mexico, are a different sort of generation: they put off breeding and live for months, where their parents and grandparents lived for weeks. In spring they start north, lay eggs and die, and it takes several more short lives to reach the top of the map again. So the butterflies that settle into the fir forests each winter have never been there. The last monarch in the family to see those trees was a great-great-grandparent, and nobody can yet fully say how the directions survived four lives that never overlapped. Every winter the forest fills with travellers who are all, without exception, arriving for the first time, and they still pick the right mountain.

In 1892 Samoa moved itself to the other side of the International Date Line, and to do it the islands lived Monday the 4th of July twice. The change was said to suit the American traders, whose calendar Samoa now shared, and the doubled day was American Independence Day. In 2011 Samoa moved back, to share a calendar with Australia and New Zealand, and this time a day had to go: Thursday the 29th of December was followed by Saturday the 31st, and Friday the 30th never happened there at all. So a country has had one day too many and one day too few, a hundred and nineteen years apart, and the books balance. What I keep turning over is that both times the date was not a fact about the islands. Nothing about the sun over Apia changed. It was a fact about who you most needed to be talking to on the same day.

A waiter sets down the plate and says enjoy your meal, and you say you too, and the waiter goes back to the kitchen, where there is no meal. Almost everyone has done it once and winced. But it isn’t a slip of meaning. A wish has come your way, and the answer to a wish is to send one back, and that answer is right so often, after have a good day and take care and see you soon, that it has been fastened to the turn in the conversation rather than to the words in it. The mouth answers the shape before the ears have checked what was inside. What makes it hard to stay embarrassed is that nothing unkind got through. Everything you meant arrived. It was just addressed to a meal that wasn’t there.

In 1960 Frances Kelsey joined the US Food and Drug Administration, and about a month in she was handed only the second drug application she had ever reviewed: a sleeping pill called Kevadon, already sold in Europe as thalidomide. The rules of the time said a drug went on sale automatically if the agency had not turned it down within sixty days, so the safe-looking thing was to let the clock run. She kept stopping it instead, asking for more evidence each time. That December a letter in the British Medical Journal reported painful nerve damage in adults taking the drug, and Kelsey thought that was not the kind of side effect a simple sleeping pill should have, and wondered what it might do to a baby before birth. By the time the company withdrew its application in March 1962, thousands of children in Europe had been born with damaged limbs, and she had been right. What strikes me is that the law had made approval the thing that happened when nobody did anything. Her whole contribution, the one a president gave her a medal for, was refusing to be nobody.

In 1611 Johannes Kepler guessed that the way a greengrocer stacks oranges, each layer sitting in the hollows of the one below, is the tightest way to pack equal balls, filling a little over 74 per cent of the space. Every greengrocer already believed it. Proving that nothing cleverer could ever exist took until 1998, when Thomas Hales handed in a proof that leaned on enormous computer calculations. A panel of twelve referees worked on it for about four years and then reported that they were 99 per cent certain it was right, and could go no further. So Hales spent another eleven years teaching a computer to check every step, and in August 2014 it agreed. The oranges were right on the first day. The last one per cent was the part about how far you can trust someone who says they have looked everywhere.

Explode began in a Roman theatre. Explodere meant to drive a performer off the stage by clapping, ex- and plaudere, to clap, so a bad actor was clapped out of the room by the same hands that clapped a good one into staying. Applaud comes from the same verb, pointed the other way. English took explode in the 1530s to mean rejecting something with scorn, and that sense still hangs on in an exploded theory, one that has been hooted off. Only near the end of the eighteenth century did the word start to mean bursting with a bang, probably because the noise was the part everyone remembered. It is the same sound either way. What it meant depended entirely on which direction you wanted the actor to go.

Old refrigerators shut with a latch, a handle that clicked into a catch and could only be worked from the outside. Children playing hide-and-seek, or exploring a fridge left out by the curb, climbed in, the door swung to, and they could not get out. In 1956 Congress passed the Refrigerator Safety Act, and from late 1958 every household fridge sold in the United States had to open with a push of no more than fifteen pounds from inside. The law did not say how. Most makers answered it with a magnet: a strip in the door seal that holds well enough to keep the cold in and gives way to anyone who leans on it. So the small sticky resistance you feel when you pull a fridge open is not the door being stubborn. It was measured against the push of someone small, from the dark side.

In 1886 the Nix family brought tomatoes into New York from the West Indies and paid duty on them, because the Tariff Act of 1883 taxed vegetables and let fruit in free. They sued to get the money back, on the grounds that a tomato is botanically a fruit, and in 1893 the Supreme Court said they were right about the botany and wrong about the tax. Justice Gray agreed that a tomato is the fruit of a vine, as cucumbers, squashes, beans and peas are. But the law had been written in the language people actually speak, and in that language a tomato is served with the soup or the meat and not as dessert, so it is a vegetable. What strikes me is that this test sorts the plant by where it turns up in the meal, which no botanist would accept and nearly everyone already uses. It means a tomato has been a fruit to the plant and a vegetable to the person eating it the whole time, and the two never needed to agree until someone had to send a bill.

The zebra’s stripes were long explained as camouflage, or as a way of dazzling a lion. In 2019 Tim Caro and his colleagues filmed horse flies around zebras and plain horses and found that, from a distance, the flies treated them the same: they circled and came in at about the same rate. The difference was in the last moment. Over a horse a fly slowed down and landed. Over a zebra it kept its speed, failed to brake, and bumped off. Then the team put striped cloth coats on horses. Far fewer flies landed on the coats, while the horses’ uncovered heads were attacked as often as before. So the stripes don’t hide anything. The fly sees the animal perfectly well and wants it. What the stripes take away is the part where you have to judge exactly how close you are.

In 1659 France and Spain settled their border in the Treaty of the Pyrenees, and when the details were worked out the next year France was given the villages of the northern Cerdanya, a high valley the new line ran across. Llívia sat among them and stayed Spanish, because it was not a village. It was a town, a vila with a charter, and the treaty had said villages. So it is still there: a Spanish town and its fields entirely surrounded by France, joined to Spain by a road under two kilometres long that stayed a neutral road until both countries joined the Schengen area. Most borders are drawn round what people wanted to keep. This one was drawn round a noun, and the town inside it has spent three and a half centuries being exactly as important as the word said it was.

Plenty of people tidy the house before the cleaner comes. The dishes go into the sink, the clothes come off the chair, the worst of it gets put away, and only then does the person paid to deal with the mess arrive and find most of it gone. It looks like paying for something you have already done, and it isn’t quite. There are two cleans in it. The first is done for a stranger’s eyes and is about what the place says about you; the second is done with a cloth and is about the place. Nobody hires help with the first one, because the whole point of it is that nobody sees you needed any.

When Dmitri Mendeleev laid out his periodic table he left gaps in it, and for some of them he described the element that ought to be there. One, below aluminium, he called eka-aluminium and gave it a weight, a low melting point and a density of about six times that of water. In 1875 Paul-Émile Lecoq de Boisbaudran found a new metal in a zinc ore by its spectrum and named it gallium. It fitted the description well, except that he measured its density at 4.7. Mendeleev, who had never held a grain of the stuff, said the number was wrong. Lecoq de Boisbaudran, who had the metal in front of him, measured again and got about 5.9. It is an odd position to be in, holding a new element and being corrected about it by a man who has never seen it. But Mendeleev had not been looking at the metal. He had been looking at the hole it had to fit.

Take the curve y = 1/x from x = 1 outward, spin it around the axis, and you get a trumpet that narrows forever and never closes. Evangelista Torricelli published the shape in 1644 and showed what upset people about it: the horn holds a finite amount, exactly π if the units are kept simple, while its inside surface is infinite. So you could fill it with paint and still never manage to paint it. The way out is that filling it is painting it. Pour the paint in and it coats every bit of the wall, only the coat gets thinner the further down the horn it goes, far thinner than any brush would leave it. The paint was never short. What ran out was our idea of how thick a coat has to be before it counts.

Dismal used to be a date. Medieval calendars marked two unlucky days in every month, twenty-four in a year, and called them the dies mali, the evil days, which reached English through Anglo-French as dismal. You could look one up in advance and decide not to start a journey on it. Nobody was quite sure why those days were bad. They were also called Egyptian days, and some put them down to Egyptian astrologers, others to anniversaries of the plagues of Egypt. In time the calendar fell away and only the mood stayed, so a dismal day is now something you find out about when you open the curtains. The word began as a forecast you could read ahead of time and ended up as weather you can only report.