John Jeffries (1744-1819),US physician,meteorologist and balloon aviation pioneer. Jefferies was a British military surgeon during the American Revolution. In London,in 1784,he made a scientific study of the air at high levels. He approached French balloonist Jean-Pierre Blanchard and (with a barometer,thermometer,hygrometer,electrometer,and mariner's compass) they made two flights. His observations were passed to the Royal Society. The first flight was from London to Dartford,the second in 1785 making the first aerial crossing of the English Channel |