What's In Your Pocket?

THE GREEKS HAD A WORD FOR IT

- Peter Garrison

My mother, who fortified herself for any aerial voyage with either Miltown or Chivas Regal, would later revisit with perverse relish each “air pocket” the plane had encountered. I’m not sure what she believed an air pocket consisted of, but I suppose it was something like the “region of low pressure causing an aircraft to lose altitude suddenly” that you still find if you Google the phrase today.

You would not suppose that awareness of air pockets could much precede the Wrights, but in fact, the earliest reference I have encountered is in a biography of the Roman general and statesman Titus Quinctius Flamininus, who in 197 B.C. liberated a number of Greek city-states from Macedonian control. Writing some 250 years after the event, the author, Plutarch, describes how a large gathering of Greeks gave out such a shout of joy at the announcement of their emancipation that passing crows fell from the sky.

He pauses in his narrative to ponder this remarkable event. “The disruption of the air must be the cause of it. For the voices, being numerous, and the acclamation violent, the air breaks with it, and can no longer give support to the birds, but lets them tumble, like one that should attempt to walk upon a vacuum. ... It is possible, too, that there may be a circular agitation of the air, which, like marine whirlpools, may have a violent direction of this sort given to it.”

The mixture of credulity and careful analysis is characteristic of ancient authors; we, or at least the irreligious among us, simply dismiss implausible stories of long-past events as mere fables. But it is also interesting to see that a first-century Greek, who was a newborn babe as far as the mechanisms of flight and the behavior of air are concerned, nevertheless came pretty close to describing what today we would call “loss of lift” and “turbulence.”