On the second Sunday of March the clocks in the kitchen jump an hour and the one in the truck does not, and for a week or so the town runs on two times at once. The phone knows. The microwave doesn't. Somebody is late to church. Somebody else stands in the kitchen at what the stove says is one-thirty in the morning and what the phone says is two-thirty, and thinks, for about a second, about what time actually is.
The plant across the water does not spring forward. Or rather, it does the same thing the rest of the town does with its wall clocks and then goes on exactly as before, because a continuous process has no use for an hour that appears out of nowhere. The furnaces on the channel were at temperature at one fifty-nine and they are at temperature at three o'clock and the chemistry in between did not skip. Somewhere on a log sheet there is a night with no two-thirty on it, a line that goes straight from the one o'clock reading to the three, and the pressures and the flows on either side of the gap match up as if nothing had happened, because nothing had. The only person who notices is the operator who came on the evening before expecting twelve hours and goes home after eleven. In the fall the same person works thirteen. Over a year it comes out even. Over a career it comes out to a story you tell the new hires.
It is a good week to think about what a clock is, because for most of human history there wasn't one, and the town did fine.
There was the sun. The sun comes up over the bay and crosses and goes down behind the town, and the moment it stands highest is noon. Not twelve o'clock. Noon. The two used to be the same thing and they are not anymore, and the difference matters. Every place on earth has its own noon, because the sun can only be highest over one line of longitude at a time. A town fifteen miles east of here sees the sun peak about a minute before we do. Galveston's noon and Houston's noon are a couple of minutes apart. Before the railroads, that is how time was kept: each town set its courthouse clock by its own sun, and a traveler reset his watch at every stop, and nobody thought this was strange because there was nothing to compare it to.
The railroads could not run that way. A timetable with a different noon at every station is a collision waiting to happen. So in November of 1883 the railroads of the United States and Canada agreed among themselves to divide the continent into zones an hour wide and to run every train in a zone on one clock. The government did not make them do it. The government did not get around to making it law until 1918, thirty-five years later. Standard time was invented by people who needed to know when the freight would arrive, which is a Baytown kind of reason.
Central Time is set to the sun on the ninetieth meridian, which runs roughly through New Orleans. We are about five degrees of longitude west of that. The earth turns fifteen degrees an hour, so five degrees is about twenty minutes. On an ordinary winter day, when the clock in the kitchen says twelve, the sun over the bay still has about twenty minutes to climb. In the summer, with the clocks pushed forward, it has about an hour and twenty. The sun stands highest over Baytown at something like one-twenty in the afternoon. Nobody notices, because nobody looks up at one-twenty and asks. But it is true, and it is the reason the light lasts so late on a June evening here, and why the mornings in daylight time are so dark for a few weeks in March.
There is another thing. Even the sun is not a reliable clock, not to the minute. The earth's path around it is not a perfect circle but a slightly squashed one, and the earth moves faster along it when it is nearer the sun, in January, and slower when it is farther, in July, so the sun seems to hurry across the sky in one season and dawdle in another. On top of that the axis is tilted, and the sun's yearly track runs slantwise across the equator that our clocks are measured against, so even its steady motion gets counted unevenly. The two effects add and cancel through the year, and a sundial and a good watch disagree by as much as a quarter of an hour, depending on the month, and they are both right. The watch keeps an average sun. The dial keeps the real one. Astronomers have a table for the difference and have had one for centuries. If you photographed the sun from the pier at the same clock time every week for a year and laid the pictures over each other, the sun would not sit in one spot; it would draw a tall, lopsided figure eight on the sky, high in June, low in December, leaning one way in autumn and the other in spring. That figure is the difference between the day we keep and the day we get. Put plainly, the day you set your clock by is a fiction, a smoothed-out day, the kind of day the earth would have if it behaved. It does not behave. It is a rock on a slightly bent road around a star, and it takes the road it was given.
Then there is the day itself. Ask anyone how long the earth takes to turn once and they will say twenty-four hours, and they will be wrong by about four minutes. Measured against the stars, the earth turns in twenty-three hours and fifty-six minutes. The other four minutes are the orbit: in one day we have moved about a degree along our path around the sun, so the earth has to turn a little extra to bring the sun back to the same place in the sky. Twenty-four hours is the sun's day. Twenty-three fifty-six is the earth's. We keep the sun's, because we live by the sun, but the difference adds up to one whole extra turn a year that nobody ever sees.
And even the earth's own day is not fixed. The tides drag on it. The moon pulls the bay up and lets it down twice a day, and every one of those tides is a brake, a small one, and over a century the day gets longer by about two thousandths of a second. That is nothing to a person and everything to a clock that counts atoms. Since 1972 the world's timekeepers have had to slip an extra second into the calendar now and then to keep the atomic clocks from running ahead of the planet, twenty-seven of them between 1972 and the end of 2016, each one announced months ahead and inserted at midnight on the last night of June or December. The second itself is defined by counting the vibrations of a cesium atom, more than nine billion of them, because the atom is steadier than the sky. So the finest clocks we have are set by something smaller than we can see, and corrected, every few years, to match something larger than we can feel.
So the kitchen clock is a convention set by the railroads, corrected for a meridian through Louisiana, based on an averaged sun that does not exist, pushed forward an hour by an act of Congress for nearly eight months of the year, and nudged, now and then, by a second the planet lost to the tide. It is a fine tool. It is not the time. The time is happening over the bay whether anybody reads it or not.
The plant knows this better than the town does.
A continuous process has clocks everywhere. There are clocks on the control-room screens and clocks on the log sheets and clocks in the instruments that decide when a valve moves. But none of those is the clock the process actually runs on. The process runs on rates. A furnace holds its temperature for a run of so many weeks before it has to be cleaned; the hydrocarbon passes through the tubes in a fraction of a second; a unit comes down for turnaround every few years, and the crews come in and the hotels fill and the town swells for a season. Those are the real intervals. They are set by chemistry and by steel, by how fast carbon builds up on the inside of a pipe and how long a piece of metal can be hot before it needs looking at. The plant has a calendar, but the calendar is written by the process, not the other way around.
The people who work it are on a clock that is neither the town's nor the plant's. Twelve-hour shifts, days and nights, a rotation that turns over on a schedule with its own name. An operator on nights eats supper at what the rest of the street calls breakfast, and sleeps through the noon that isn't noon, and drives home into a sunrise everyone else is driving toward. The shift is the third time, the human one, and it has to fit between the other two. It is the only one of the three that gets tired.
None of the three clocks is the thing it counts. A clock is a tally kept on the side of the work, a way of marking how much has gone by. The oldest ones were a stick and its shadow, and the shadow was the sun's doing; the stick only read it. The order has not changed. The sun crossing the bay is the work. So is the furnace at temperature. So is the operator awake at three in the morning, on the night the clocks jump, working an hour that officially never existed.
The sun does not care, and that is the comfort of it. It came up over the water at the same moment on the morning after the change as it would have on the morning before; the town simply agreed, all at once, to call that moment by a different number. The tide in the bay did not spring forward. The birds that were feeding on the flats at first light were feeding at first light. The flare on the far shore, which is the town's nearest thing to a second sun, kept the same fire it had kept all night, and would keep it all day, and nobody on the tower had to do anything special about it except go home an hour early and get the hour back in November.
Drive home at the end of a day shift in the week after the change, and the sun is still well up, full on the west side of every house on the street, an hour later than the clock thinks it should be. The clock on the dash says one thing. The phone in the cup holder says another. The microwave, when you get in, still says the old time, and will until somebody gets around to it. The sun says what it has always said, which is nothing at all, and goes on down.