Used with
permission of Maiken Naylor, University at Buffalo, Buffalo, NY, USA,
http://ublib.buffalo.edu/libraries/units/sel/exhibits/stamps
Joseph Louis Gay-Lussac (1778-1850) studied the properties of gases. Hot air ballooning was becoming a popular activity and Gay-Lussac availed himself of the new technology. He found, after balloon ascents, that the composition of the air at high altitudes is the same as at sea level, and that the earth's magnetic field remains constant with altitude. He also discovered that different gases expand by the same amount for the same rise in temperature (Gay-Lussac's Law).