#p <nat>American<o>meteorologist<n>William Ferrel<b>1817<d>1891<c>Pennsylvania<info>Ferrel explained in 1858 how the earth's rotation affects the way weather moves. The Ferrel cell, of which he conceived, is the middle latitude (30-60 degree) "wheel" of the atmosphere's general circulation as seen in the latitude-height plane. Three such cells exist in the classical view: a "direct" tropic cell and a "direct" polar cell (in which warm air rises and cold air sinks), with a reverse middle latitude cell in between.<ref>Grolier
// 20th century
#e <t>theory<t>geology<d>1912<n>continental drift<c>Germany<info>by Alfred Wegener
#e <t>geology<d>1935<n>Richter scale<c>U.S.<info>developed by American seismologist Charles Richter for measuring the strength of earthquakes.
#e <t>theory<t>geology<d>1938<n>Greenhouse effect<c>Great Britain<info>British engineer George Callendar analyses decades of temperature readings and describes what is later known as the Greenhouse effect.