Light equals life. It is precious, and we are loath to lose it. Not that the dark does not bring its own healing, life-enhancing atmosphere, but after the long pitch of winter -- especially this last one -- we are eager, anxious, impatient for more light. Nature knows that and obliges.
The worst of the dark is long over. The Winter Solstice is as dark as it gets, and the light has been returning in tiny, almost imperceptible increments ever since. Creeping back by a minute each morning and evening, it has been getting lighter earlier and staying light later. The change is not as slow as it sometimes seems: 2 minutes a day x 7 days = 14 minutes a week x 4 = nearly an hour a month x 3 months = 3 hours from winter to spring.
The length of day is determined by the rotation of the Earth around its axis, and it is always the same -- 86,000 seconds -- which translates to 1,433.333 minutes, or 23.888 hours in a day. Clearly chaos would erupt if people tried to use a clock based on a 52.8-minute hour. In order to establish any sort of standardized time, it was necessary to round off the numbers and create a day of 24 hours, which could then be easily divided into an even number of hours and minutes.
The length of a day is always (with the exception of an occasional leap second) 24 hours long everywhere on Earth, but the length of daylight changes according to latitude. On the equator, it never varies too far from 12 hours of light and 12 hour of dark each day, year round. At the poles, it is light for 6 months and dark for 6 months with only two sunrises per year. In the northern and southern hemispheres, the light season transforms gradually into the dark, and the dark into the light. But every place on the planet experiences an near equal amount of light and dark overall averaged over a year -- approximately 12 hours of each -- at the equator, half of every day, and everywhere else, half of every year.
While the measure of the length of a day, an hour, a minute have been manipulated for the convenience of human society, the length of daylight during any 24-hour period is fixed and cannot be tampered with. However, we have figured out a way to ensure that we are able to make the best of the light that we have. Light, after all, is too precious to squander. Too expensive to do without.
This notion did not escape the notice of the notoriously frugal Benjamin Franklin. In a moment of whimsy, he wrote "An Economical Project," a discourse on the thrift of natural versus artificial lighting. On a trip to Paris, he noticed that even though the sun rose at 6 a.m., the Parisians rose at noon, which meant that they slept through six hours of sunlight and stayed up until late, burning the midnight oil, as it were, since they spent their six-hour evenings by candlelight. When he calculated the number of Parisians by the number of pounds of tallow they used by the number of hours they burned their candles, he was appalled. Why not just get up earlier and enjoy the light? This audacious insight was the seed of the concept of Daylight Savings.
The idea was first advocated seriously by London builder William Willett in his 1907 pamphlet "Waste of Daylight," which proposed advancing clocks 20 minutes on each of four Sundays in April, and turning them back by the same amount on four Sundays in September. He wrote, "Everyone appreciates the long, light evenings. Everyone laments their shortage as autumn approaches; and everyone has given utterance to regret that the clear, bright light of an early morning during spring and summer months is so seldom seen or used."
It took World War I to make the scheme of saving daylight a reality. In an effort to conserve the fuel needed to produce electric power, Germany and Austria took the initiative to advance the clock an hour at 11 p.m. on April 30, 1916, until the following October. Other countries immediately adopted this action: Belgium, Denmark, France, Italy, Luxembourg, Netherlands, Norway, Portugal, Sweden, Turkey, and Tasmania. Nova Scotia and Manitoba adopted it as well, with Britain following suit three weeks later. In 1917, Australia and Newfoundland began saving daylight, followed by the United States in 1918.
During World War II, President Franklin Roosevelt instituted year-round Daylight Saving Time, called "War Time," from Feb. 9, 1942, to Sept. 30, 1945. In Britain, the benefits of Daylight Savings Time or Summer Time were doubled during World War II, when the Brits put their clocks two hours ahead of GMT, creating Double Summer Time. During the war winters, clocks remained one hour ahead of GMT.
Daylight Savings Time is thought to be an effective way to cut back on the use of energy. The theory is that energy use and the demand for electricity for lighting homes is directly related to the times when people go to bed at night and rise in the morning. In the average home, 25 percent of electricity is used for lighting and small appliances, such as TVs and stereos. A good percentage of energy consumed by lighting and appliances occurs in the evening, when families are home. By moving the clock ahead one hour, the amount of electricity consumed each day decreases.
The Energy Policy Act of 2005 extended Daylight Saving Time in the U.S. starting in 2007 by beginning DST three weeks earlier in the spring and one week later in the autumn giving us more of a good thing. It is a small, frugal contribution to the grand goal of energy conservation.
Ben would be proud.