It’s about time: humanity’s heated relationship with the sun

This weekend you enjoyed an extra hour of sleep or revelry, if your region put the clocks back to put an end to daylight saving time.

Depending on your point of view (can you guess mine?), you’re either relishing a few more days of early morning sunlight, or resenting getting home in the dark and having to turn the light on to do your solely-indoor activities.

There’s a lot of confusion surrounding daylight saving time. From my informal poll of family members and colleagues, lots of people think that DST exists to help farmers, much like school summer holidays allowing children to stay at home during the harvest season, or that the summer hours represent the ‘true’ time, which we adjust in winter to be able to enjoy more hours of daylight when they are so scarce.

This is not so: DST is simply one of humanity’s latest attempts to wrest control of time from the dictates of the sun, a process of adaptation that’s been underway since the advent of industrialisation and artificial light in the 19th century. The changes to the sun-imposed daily routine are so great that in contrast to the extra hour of sleep you had last night, people in pre-industrial societies enjoyed an additional hour of wakefulness in the middle of the night, dividing their sleep in two.

Before the industrial revolution, the sun was the time: local observatories, or any garden sun-dial, would measure the sun’s highest point as noon. Travel in those days took so long that such local differences were usually unnoticeable. This was to the detriment of navigation: longitude could only be accurately determined by comparing the time-difference of an event (such as the rising of stars, or the sun reaching its peak) in local time and at a known reference, such as your home port.

Harrison's H4 Chronometer

The back plate of John Harrison’s fourth chronometer design.

To aid navigation, in 1735 Yorkshire carpenter John Harrison presented the design of his first chronometer, a clock which could keep the time measured at a single location while travelling. He hoped this would win him the Longitude Prize of several thousand pounds, offered twenty years earlier by the British government to the first technology capable of solving this problem. He eventually won the prize in 1765 for his fourth design, which with a heavy balance wheel could keep accurate time even when being rocked on stormy seas.

Though British ships compared time on deck to that measured at the Royal Greenwich Observatory, the idea of a regional timezone arrived a century later, alongside the high-speed medium of train travel. Due to their distance from the Greenwich Meridian, western English cities such as Bristol, Liverpool and Manchester are roughly ten minutes behind London. Now that travel between these cities could happen in a matter of hours, train timetables were a complete mess. In 1940, the Great Western Railway which connected London to Bristol adopted Greenwich Mean Time for all its operations. Later that decade, other train companies followed suit, and by the mid 1850s, almost all public clocks in British towns were showing GMT.

As well as fast travel, the Industrial Revolution brought an even greater change: with artificial light, working hours were no longer dictated by the sun. With clocks and alarms now commonplace, industrialists dreamed of factories that could work continuously through the night. Though few did in the 1800s, workers were often roused before dawn and sent home after dusk.

Bristol Corn Exchange Clock with two minute hands

The clock over Bristol’s corn exchange still has two minute hands that are ten minutes apart: one for London time, one for local.

In opposition to the draconian working practices of the 19th century, daylight saving time was proposed in 1895 by George Vernon Hudson to give people an extra hour of post-work daylight in the summer. As an amateur entomologist, Hudson wanted to use this time to collect insects. For others now accustomed to a 9-to-5 routine the full year round, by waking up an hour earlier than usual in the summer they could make full use of the daylight hours. The reversion to solar time in winter helped prevent long hours of darkness early in the morning.

Despite Hudson’s altruistic intentions, DST was eventually implemented for pragmatic reasons: to conserve coal in the First World War. Initially adopted by Germany and Austria-Hungary, other countries quickly followed. With a few exceptions, including the UK, most countries kept DST only during wartime, and rediscovered it later in the century.

One largely undocumented change that artificial lighting brought about was in the very way we sleep. In the paper “Sleep We Have Lost: Pre-Industrial Slumber in the British Isles”, historian A. Roger Ekirch shows that when people slept and rose with the sun, it was common to wake up for around an hour in the middle of the night: a dreamy, pensive time in which people would smoke, have sex, or philosophise and write poetry.

Perhaps the last record of this in Britain was in the travel diary of Robert Louis Stevenson’s journey through France’s highlands, in which he writes, “there is one stirring hour unknown to those who dwell in houses, when a wakeful influence goes abroad over the sleeping hemisphere, and all the outdoor world are on their feet.”

Stevenson, writing in the late 1800s, experienced this form of sleep only when camping far from civilisation, but before industrialisation, this was the norm even for those who dwelled in houses. Though contemporary analysis of sleep was scant, Ekirch draws evidence from diaries and poetry that reference this lost time between first and second sleeps. Modern experiments have shown people find this time of mid-night wakefulness again when left without artificial light, and liken its mental state to meditation.

More recently, the independence referendum in Stevenson’s native Scotland has brought time into question again. Since the 60s, there have been calls to keep the UK in GMT+1 the whole year round, or even to have “double summertime” from March to October, keeping in step with Central European Time. The former was trialled by the British government from 1968 to 1971, who found that traffic accidents increased in the morning and were reduced in the evening; however, with the introduction of drunk driving legislation at the same time, the overall effects are difficult to determine.

This idea is most opposed in high-latitude Scotland, where GMT+1 in the winter would mean sunrise could come as late as 10am. Scottish independence could have seen two time zones used on the British isles, with the Scots keeping a bright start to the day, and the rest of the UK marching onwards into dark mornings. Humanity’s troubled relationship with time has clearly not reached its end.

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