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No. 147:

Today let's talk about hydrogen in 1783. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

Hydrogen is a wonderful mouthful of a word. Antoine Lavoisier named it in 1783, after he realized that it makes water when it's burned in oxygen. Hydrogen means "maker of water" in Greek. But the substance was known before that. The 16th-century Swiss alchemist Paracelsus separated it, but he seems to have confused it with other flammable gases.

Hydrogen came to public attention 17 years before Lavoisier named it. The English chemist Henry Cavendish identified it. He thought it was a kind of inflammable, or phlogisticated, air. Phlogiston was the old alchemical principle of combustion. By 1783 Cavendish had also seen that hydrogen formed water when it was burned; but he didn't realize that oxygen was involved, too.

1783 was also the year the French began making balloon ascents in Paris. The Montgolfier brothers used hot air in the first manned balloon. Hot air is easy enough to come by, but its density is only a little less than the cool air around it. Whatever people thought hydrogen was, they knew it was very light -- about 1/15th the density of air. It had terrific lifting power in a balloon.

The champion of hydrogen-filled balloons was Alexandre Charles -- a French physicist. He flew an unmanned hydrogen balloon just before the Montgolfiers' flight, and a manned one only 3½ months after it. He invented a hydrogen generator that worked by mixing huge quantities of sulfuric acid with iron filings.

London sneered at the French balloons, but there was a better intellectual climate further north. In Birmingham, movers and shakers like Watt, Priestley, Wedgwood, Boulton, and Erasmus Darwin met in a scientific club called the Lunar Society. They weren't interested in flying, but they saw scientific possibilities in the French balloons.

In 1784 Watt and Boulton built an unmanned paper balloon. They filled it with air and hydrogen and launched it with a timed fuse. They wanted to find out whether the reverberating sound of thunder was the result of repeated claps or of echoes. The experiment was inconclusive, but the explosion they set off was apparently a grand and soul-satisfying one.

The early balloonists put words like inflammable air and phlogiston on every tongue. These huge hydrogen-filled spheres dressed the sky in fantastic colors and caught the public's fancy. Balloons hurried the process of taking chemistry out of the alchemical laboratories and tying it to the high technology of the Industrial Revolution.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)

Rolt, L. T. C., The Aeronauts: A History of Ballooning 1783-1903. New York: Walker and Company, 1966.

This episode has been greatly revised as Episode No. 1604.


(From the 1897 Encylopaedia Brittanica)
Alexandre Charles' hydrogen balloon