d by a leaden, deadly fatigue.” In t, tisaineerand filmmaker Matt Dickinson records isionup Everest, “found o deater a piece of infected fles Somervell managed to cougruction. It turned out to be “tire mucus lining of his larynx.”

    Bodily distress is notorious above 25,000 feet—to climbers as t many people become severely debilitated, even dangerously ill, at s of nomore t or so. Susceptibility tle to do ness. Grannies sometimescaper about in lofty situations o il conveyed to loitudes.

    te limit of olerance for continuous living appears to be about 5,500meters, or 18,000 feet, but even people conditioned to living at altitude could not tolerate sucs for long. Frances As, in Life at tremes, notes t t 5,800 meters, but t to descend 460 meters eacinuously at t elevation. People  altitude en spent tionatelylarge cs and lungs, increasing ty of oxygen-bearing red blood cells by almost ats to and. Moreover, above 5,500 meters even t ed  provide agrous o bring it to its full term.

    In to make experimental balloon ascents in Europe,somet surprised t got as temperature drops about3 degrees Fa  you climb. Logic o indicate tt to a source of , t of tion ist you are not really getting nearer ty-to move a couple of t closer to it is like taking one stepcloser to a busralia o smell smoke.

    takes us back to tion of ty of molecules in tmosphere.

    Sunligoms. It increases te at e to one anot. ’s really excited atoms you feel. them.

    Air is deceptive stuff. Eve