The Theory of Clouds

Stéphane Audeguy, Harcourt, Inc. 2007. English translation by Timothy D. Bent

For quite a long time, Kumo told her, scientists never thought about why the sky was blue. It was of course the same then as now – apparently monochromatic yet consisting of a nearly infinite variety of shades. Thousands of poets wrote about it being azure or cerulean, but not a single scientist bothered to explain why this was so. The poets’ evocations were scarcely better than what the scholar-priests offered, for they were not truly interested in the sky’s blueness so much as in turning it into a symbol – the color of eternity from the palette of God. It was as if they couldn’t accept the idea that the blue was simply and sublimely of its own creation.

Centuries passed and as science became less a servant of the church the skies were emptied of angels and divinity, filled instead with men on balloons or planes. What came to be understood was that the sky only seemed blue. Explanations followed as to why this was so. The sun has no sense of color, the light it emits is of no color in particular or, rather, all of them. It bombards the Earth atmosphere with light of every wavelength, from red to violet and everything in between – orange, yellow, green, blue and indigo. But these colors never reach us; as soon as they reach the upper layers of the atmosphere they strike up against tiny air molecules. These air molecules diffract small quantities of light, though not in uniform fashion – they are better of diffusing shorter waves of light than longer ones. That’s why the air in the sky won’t diffuse red, orange or yellow light. But it is very good at diffusing blue, and better still at violet. Most of the colors emitted by the sun thus never reach our retina. That, say scientists, is why the sky is violet. So why does the sky look blue and not violet? Because the eyes of men, even the eyes of men of science, are unable to distinguish violet. We perceive the sky’s color as blue just as we sense that the earth is flat or that the sun rises and sets every day.

Increasingly, people – ordinary observers, devoted amateurs, gentlemen farmers – began keeping weather journals as they were called, in which, day after day, they noted wind direction, the state of the sky in the morning and evening, rainfall amounts, and so forth. The more people shielded themselves from the weather the more they seemed to talk about it, perhaps to pass the time. Meteorologists were persuaded they were on the verge of wrestling from the rain and wind all of their innermost secrets. Meteorological societies were formed, congresses convened, and journals published.

These men of science advanced things. Little by little they learned how clouds formed – doing away with a number of even the venerable Luke Howard’s own hypotheses on the subject. They had no difficulty getting funding for their research, because their interests intersected perfectly with a seemingly infinite number of financial interests. Steel0hulled ships, very often British and growing in number, were plowing the seas of the world; large office buildings were going up in Geneva and Washington and Berlin and Paris, in which workers used rulers and ink pens to create rectilinear boundaries along what had previously been beautifully round.

Empires built to last a thousand years were founded and then disappeared in less than a hundred. More and more people went off to fight and die in distant corners of the world, in villages with strange-sounding names, villages whose existence they had not known of six months before – like Sebastopol or Falluja. The fate of the world depended upon what happened on the seas: It was a war of commerce, as much as war of the more traditional sort. England was in its Golden Age, dealing in spices and rare perfumes, amassing diamonds and opals, construction white-stoned temples to commerce in its enormous capital city.

Now that the island nation of sailors ruled the universe, weather became a serious matter. On Septembre 5, 1860, the Times of London published its first weather announcement. Five years later, on April 30, 1865, Admiral Robert Fitzroy, director of the Meteorological Department at the National Chamber of Commerce, committed suicide because his department had issued an egregiously inaccurate forecast and the press had hounded him for it. As the world was being circumnavigated more and more often, and more and more quickly, it was being learned that climatic phenomena did much the same thing. Simultaneously, it was being learned how high the costs of not understanding the sky and its movements could prove. The Agriculture Ministry had estimated that the total annual value of agricultural production worldwide, including horticulture and tree-farming, to be somewhere around 100 million pounds sterling, and, estimating that an annual 5 percent growth in productivity would result from more precise meteorological predictions and their communication to those concerned (farmers, for example), reliable forecasting had a potential value of 20 million pounds sterling. Simply identifying clouds would no longer do. One had to predict their movements, their behaviour. In 1879, the inhabitants of Dundee and the entire region were thrilled when a metal bridge was constructed to span the Bay of Tay, making it no longer necessary to go around this body of water, reducing travel time to Edinburgh by a three full hours. Britani’s finest engineers had designed the bridge.

Several times a day, heavy iron trains crossed the bridge without causing so much as a shake. A few journalists speculated about the danger of conveyance at such high speeds – close to thirty miles an hour – that would be unleashed upon the world. In the spring of 1879, after five months of reliable service, the magnificent new bridge tumbled into the river whose waters it spanned, taking with it the train that happened to be crossing it and all its passengers (Note of Actually the disaster took place on December 28, 1879, not in spring). The collapse was blamed on a series of strong wind gusts that none of the engineers had been imaginative enough to take into account. The newspapers were savage in their denunciations. Public opinion turned sour. A few elected officials tendered their resignations and, as always in cases such as this, someone took his life. Several amateur meteorologists wrote memoirs establishing that the architect had not considered wind speeds in the region. It was decided that a new bridge should be built in the same spot; this one, however, would not collapse.

Despite the occasional setbacks, British technology was unrivaled in the world; at the beginning of that same year, for example, it had permitted Her Majesty’s Army to slaughter eight thousand Zulu warriors during the course of several weeks in southern Africa. The Zulus had charged across a plain on foot, spears in their hands, using wooden shields covered with zebra skins, straight into professional soldiers equipped with the finest rifles available. On March 29, 1879, at the Battle of Rorke’s Drift, a regiment withstood a siege that endured for several days and killed a thousand native warriors in the process. Those who survived the siege were decorated.

The great and powerful nations of Europe were seeking a way of predicting storms. There were of course always storms, as well as farmers who feared them. But never before had these storms caused quite so many factories to be blown away, or house roofs to be carried off, or cattle and men sent to their doom. In short, never before had so much been at stake. On November 14, 1854, during the Crimean War, a number of warships and commercial vessels – a total of thirty-eight of them, all flying French colors – sank in the middle of Balaklava, in the North Sea. Four hundred souls were lost. Napoleon III summoned the Minister of War, to learn how he could have managed to lose so many lives and an entire fleet, including the mighty three-masted Henry IV. In an attempt to save face, the Minister of War in turn summoned the director of the Paris Observatory. The director’s name was Urbain Le Verrier. Le Verrier had no difficulty demonstrating to the minister that the evening before it had hit, the storm had been brewing over the Mediterranean, and that two days before this it had been attacking the inhabitants of Europe’s northwest regions. A telegram might have averted the whole disaster. Le Verrier was given an audience with the emperor, who wanted to know how such a thing might be accomplished. The director then wrote to every amateur astronomer and meteorologist he could find throughout Europe. Most scientists of the day spent most of their time writing each other about their discoveries anyway. The director’s request was straightforward: Could his honored colleagues relay to him their observations about the weather in their regions between November 12 and November 16? He received two hundred and fifty replies, which he posted on a map of Europe in order to track the storm’s path. Such a system had a fatal flaw of course. What good was predicting weather that had already happened? Le Verrier therefore was allocated funds to establish weather stations throughout his native land. The era of individual weather-watching had ended; the moment of the network had arrived. Before long, other countries – Holland, England, Sweden, and Russia – followed France’s example.


Clouds. Image : Megan Jorgensen