IELTS Reading: Flow-chart completion

Until the middle of the nineteenth century, the time in an English town was the time the sun said it was in that town. Noon was the moment the sun reached its highest point, which happens progressively later as one travels west, so that when a London clock struck twelve a clock in Bristol, correctly set, stood at about ten minutes to. Nobody found this inconvenient, because nobody could travel fast enough for it to matter. A coach took the best part of a day to cover the distance over which the discrepancy accumulated, and a letter took longer still.

The railway ended that arrangement, and it did so for an entirely practical reason. A timetable is a promise made in a particular time, and a company running trains across a hundred miles of country cannot print one if every station on the line is using a different noon. The Great Western adopted London time throughout its network in 1840, other companies followed, and within seven years most of the railways in Britain were running on what people began to call railway time. Towns adapted at their own pace and with varying grace. A clock installed in the Bristol Corn Exchange was given two minute hands, one for the railway and one for the town, so that a merchant could see at a glance which world he was operating in.

For forty years the position remained peculiar: the country in practice ran on one time while the law recognised local solar time, and the difference was occasionally decisive in court, where a case could turn on whether a deadline expired at the local minute or the railway one. Parliament settled the matter in 1880, defining the time meant by any expression of time in any Act or legal document as the mean time of the Greenwich meridian. What had been a convenience of the transport industry became the law of the land, and it had taken four decades for the statute to catch up with the timetable.

North America had the same problem on a far larger scale, and solved it without legislation at all. By the early 1880s American railroads were operating on dozens of different company times, and a traveller changing trains needed a published table simply to convert between them. Rather than wait for governments, the railroad companies agreed among themselves to divide the continent into a small number of bands, each an hour apart, and to adopt the scheme on a single day. On 18 November 1883, clocks in many cities were stopped or advanced to fit, producing what the newspapers called the day of two noons. Congress did not legislate on the subject for another thirty-five years, by which time the arrangement it confirmed had long been universal.

The international settlement came a year later, at a conference in Washington convened to select a single meridian from which the world's longitude and time would be reckoned. Greenwich won because most of the world's shipping already used charts based on it, which is to say that the decision had in practice been taken by mariners before the diplomats assembled. The vote was not unanimous: one delegation opposed the resolution and two abstained, France among them. France then declined to use the word Greenwich in its own legislation for a further quarter of a century, defining its legal time instead as Paris mean time delayed by nine minutes and twenty-one seconds, which is the same instant described with dignity intact.

The consequences went well beyond the railway. A standard time is the precondition for a great many other things: the shift that begins at eight, the broadcast that starts at seven, the market that opens at nine, the school bell, the appointment made between strangers in different towns. It also severed a connection that had held for the whole of human history. Under the new arrangement, the clock striking twelve no longer told anybody that the sun was overhead, and at the edge of a zone it may be nearly an hour out. We stopped taking the time from the sky and began taking it from each other.

Since then the zones have drifted away from geography for reasons that are mostly political. A country may keep a single time across a span of longitude that ought by rights to have five, so that in its far west the sun rises at ten; a country may sit on the meridian of its western neighbour rather than its own for reasons dating to a wartime alliance. Daylight saving, introduced during the First World War to reduce fuel consumption, survives in some regions and has been abandoned in others, and proposals to end the twice-yearly change have been debated for years without resolution. The pattern is always the same. A standard is worth having only because other people are using it, which is exactly what makes one so difficult to change once it is in place.