Raise a toast to William Henry, the British chemist. Born on this day in 1774, Henry is best known for his studies of the solubility of gases in liquids. In work published in 1803, he outlined what is probably his most famous finding, now known as Henry's law: When temperature is constant, the solubility of a gas in a liquid is proportional to its pressure. By contrast, pressure has an insignificant effect on the solubilities of solids and liquids.
Henry's law is important to divers and to champagne drinkers. High pressure in deep water causes more nitrogen to dissolve in the blood. If a diver ascends too rapidly, the nitrogen can bubble out of solution, causing a painful and potentially fatal condition called "the bends." High pressure in champagne bottles--and other fizzy drinks--keeps carbon dioxide dissolved.
In 1805, Henry experimentally confirmed the composition of ammonia, and later the compositions of methane and ethane. His early experiments on the composition of hydrogen chloride and hydrochloric acid were published as a successful textbook, Elements of Experimental Chemistry, which ran to its 11th edition by 1829.
[Source: Roy Porter, Ed. The Biographical Dictionary of Scientists, Second Edition. Oxford University Press. 1994.]