Windswept_ The Story of Wind and Weather - Marq de Villiers [121]
Apart from the invention of sailing ships and windmills, and then aircraft, humans were slow both to understand and then to use local winds, and slower still to copy natural examples readily at hand.
Take the example of air-conditioning—the cooling of uncomfortably overheated air. I've already mentioned that termites "invented" or discovered or at least used air-conditioning. When I was a boy, we once demolished a termite mound (not out of malice, only practicality—crushed and rolled out, termite earth makes the best "clay" tennis courts in the world, and my uncle Blen was paying us pennies a wheelbarrow-load), and I saw for myself how the insects had angled ventilation chambers into the wind to bring cooling air deep down into the earth. They had even invented pressurization; there were dead-end chambers where the winds were compressed before being redirected even deeper in the mound, deep down where the queen lives. Termites invented air-conditioning, what, a hundred million years ago? Humans had to wait until fairly recent historical times for a version of it. Early human-created air-conditioning systems simply consisted of hanging damp rags in windows and doors, where air currents would cause evaporation, and thus cooling, an effect arrived at empirically, with no knowledge of the mechanics involved. Later, the system was reinvigorated by the Roman emperor Varius Avitus, who ordered ice and snow from nearby mountains to be placed in public parks for the same reason.
Other cultures have developed other devices for cooling the air, or at least fending off the extreme heat. The desert nomads in the Sahara, where damp rags are not an option, developed a simple wind flow device consisting of a horizontal layer of fabric suspended on poles above a tent, which has the effect of creating differential heating patterns, which produce a breeze between the two layers, muting the brutal heat of the Saharan sun. Air cooling dictated the layout of the Egyptian city of Kahun in pharaonic times; at around 2000 B.C. the Kahunian power elite made sure their houses were oriented to the cooler north winds, while the slave classes were packed in higgledy-piggledy to the south. In pre-Raj times, the city of Hyderabad in India contained houses with tall central air shafts and air scoops on the roof oriented to the winds, that drew cooling air into the interior. This was the same pattern developed, or imported, by the Swahili traders of Zanzibar, a system still used in that city, where the stone houses tend to be five or six stories tall, with the cooler sleeping rooms on the lower levels and the warmer public rooms higher up (the kitchen is typically on the roof). The Romans used similar ducts for heating, as the Incas did for their smelting furnaces.
In this sporadic, episodic way, a technical mastery of the winds developed. Human cultures moved quickly beyond having to sacrifice virgins to placate the wind gods; even Aristotle's sketchy knowledge of meteorology represented real progress, in the sense that it sought a technical grasp of how wind actually worked. But for an understanding of the theory behind it natural scientists had to wait until Leonardo had grasped the principles of conservation of mass; and even then nothing could be confirmed until Torricelli, Galileo, Sir Francis Bacon's Historia Ventorum, and Isaac Newton's theories of mechanics. As late as the nineteenth century engineers were still operating with hazy theoretical principles and had to resort to actual testing to see what was needed. A good case in point was Gustave Eiffel's design and construction of the Eiffel Tower for the French Exposition, which led to considerable advances in atmospheric science—Eiffel's wind-load design assumptions were among the earliest sophisticated attempts to understand static wind loading on buildings.