Tidetable

No. 9 · November 2026

Tidetable

Essays and letters on the things that keep time.

Written by Ilse Marrow in Trieste since 2023.

The latest essay9 minutes

The ball that falls at one

Since 1833 a red ball has dropped down a mast in Greenwich at one o'clock. It is the slowest way ever devised to send the time, and the most honest.

Every afternoon at five minutes to one, a red ball climbs halfway up a mast on the roof of Flamsteed House in Greenwich, and stops. At two minutes to one it climbs to the top. At one o’clock exactly, it falls.1 That is the whole performance, and it has run since 1833.

1The times are those the Royal Observatory gives for its visitors. The ball runs on Greenwich Mean Time in winter and on British Summer Time in summer, so in summer it falls at noon by the sun’s reckoning, give or take.

On the Thursday I went to see it there were about forty of us in the courtyard below, most of us holding up phones to film a ball doing what balls do.

I had come to look at a clock with no face. A time ball tells one time a day, to anyone who can see it, and it does so without a sound. It does not tick, it does not strike, it has no hands. For five minutes it gets ready, and then for less than a second it tells you something precise.2 It was built for people who needed that second more than they needed anything else the clock could have said.

2Watch the top of the mast, not the bottom. By the time the ball lands, the moment it was announcing is already gone.

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The letter

One letter, on the first Sunday of the month.

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From the notebook

The cellist again

The man with the cello case was on the 23:52 again. He slept from the first station, as before, with one hand on the case as if it might leave without him. I have now seen him four times and never seen him awake, and I have decided that I do not want to know where he plays. Some regulars are better left as weather.

Four minutes, a follow-up

After the essay about my kitchen clock, readers sent me their own wrong clocks: fast, slow, and in one case running backwards on purpose. The most common gap is five minutes. The record is twenty-two, held by a reader who says she has never once been late and never once known what time it was. I am printing no names. Every one of these clocks is a household secret.

The station clock stops for a minute

The big clock in the station hall does something I had never noticed before this spring: its second hand sweeps round a little faster than a second, then stops at the top of the minute and waits, perfectly still, for a signal from somewhere else. Then the minute hand jumps and it begins again. It keeps time by being briefly wrong and then agreeing. I can think of worse ways to live.

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