Last Friday, it was 90 degrees in Washington, and I gave my thanks once more for Willis Carrier’s good idea. The air conditioner celebrated it’s hundredth anniversary last week; Carrier designed the first air conditioner in 1902 to improve the consistancy of a the Sackett-Wilhelms Lithographing and Publishing Company’s work during the humid Brooklyn summer; the temperature and humidity fluctuations had made quality control at the printing plant nigh impossible. Carrier’s invention has had a huge impact on America and the world, but was really just the end result of millenia spent trying to cool homes; Susan Roaf’s history of climate control dates the icehouse (where blocks of ice were stored) back to 1800 B.C. Carrier did not invent the refrigeration process. A portable methyl ether compression refrigerator had been invented by 1873 by Karl von Linde; the compressor refrigerator relies on a simple three-step process. A gas is compressed, gaining pressure. It then flows into a condenser, which increases the pressure and density on the gas, forcing it to become a hot liquid. Heat from this liquid is vented into the room as it flows through a pipe. Eventually the liquid reaches an evaporator, where it turns to a gas, becoming markedly colder in the process. This cold gas chills the food as it returns to the compressor, starting the cycle anew.

A number of people had experimented before von Linde, some creating working experimental devices. A French engineer, Ferdinand Carre, developed the ammonia compression refrigerator and the first commercially viable ice maker; others, such as the Crosley Ice Ball, would follow. The early twentieth century was a heady time for refrigeration enthusiasts (who had their own trade journal, Electric Refrigeration News), as compression refrigerators slowly made their way into American homes.

Until then, food was cooled at home in the ice box, which was simply that: a box designed to hold ice. This ice was laboriously chopped out of ponds, shipped to urban centers, and stored (packed in sawdusts) in icehouses to last into the summer; it would be delivered to customers’ homes as they needed it. The process, which in some places lasted well into the twentieth century, was revolutionized by Nathaniel Wyeth, who invented a horse-drawn ice plow, eleminating the need for tedious hand-chopping of the ice blocks. Wyeth’s employer, Fredric Tudor, "The Ice King", built a commercial empire shipping ice from Wenham, Massachussetts, to the southern United States and throughout the British Empire. Although the ice industry existed throughout New England (at Cape Pond in Gloucester, Massachussets, for instance), Wenham’s ice was the best known; it was the brand Queen Victoria prefered.

Some accuse Tudor of being behind the failure of Dr. John Gorrie. Gorrie, a Florida physician, had become convinced that malaria could be cured by cold and toiled at developing a working ice maker. He developed an air-expansion device (for which he received the first American patent for a mechanical refrigerator), but ruined himself financially in the Quixotic quest to bring ice to Florida. Gorrie was dismissed as a crank and never got to see the benefits of his invention. He died young and almost entirely forgotten.

Carrier’s great invention was not refrigeration; it was humidity control. As anyone who has ever had to defrost a freezer knows, cooling generates humidity. Carrier had, counterintuitively, devised a means by which a spray of droplets could dry the humid air. (The moisture condenses on the droplets, almost like rain forming in a rain cloud.) This was the crucial breakthrough; although Professor Roaf cites others, including Gorrie and Charles Piazzi Smith who had attempted to cool buildings using refrigeration, Carrier made the humidity it generated tolerable. In 1906, he began using his invention to cool Southern textile mills; soon air-conditioned office buildings, movie theaters, and motels began to spring up, and the battle against summer heat moved into a new phase.

The Smith that Roaf mentions is presumably Charles Piazzi Smyth, the meteorologist, early spectronomy observer, and Royal Astronomer of Scotland who is perhaps better remembered today as an Egyptian pyramid obsessive. Smyth would have been gratified to know that just as the ancient Romans used ancient Egyptians left shallow dishes of water out in the Delta night, where evaporation and the evening cool would form ice to chill food and drink. Liquids were placed in wetted pottery and fanned by slaves; evaporation kept them cold. The principal is the same as that used in the compression refrigerator, and it shows that some things don’t change: if you don’t have air conditioning, a cold drink is the next best thing.