On April 15, 1875, pilot Th矇odore Sivel, engineer Joseph Croc矇-Spinelli, and civilian Gaston Tissandier, took off in the balloon named Zenith and were able to reach in a balloon the unheard-of altitude of 28,000 feet. Although the men carried bags of oxygen-air mixture aboard the Zenith, Sivel and Croc矇-Spinelli both died of asphyxiation (hypoxia), when the balloon reached extremely high altitudes. Tissandier survived, but became deaf. Gaston Tissandier (November 21, 1843 - August 30, 1899) was a French chemist, meteorologist, aviator and editor. Adventurer could be added to the list of his titles, as he managed to escape besieged Paris by balloon in September 1870. He founded and edited the scientific magazine La Nature and wrote several books.