Naismith's rule
/ (ˈneɪsmɪθs) /
noun
mountaineering
a rule of thumb for calculating the time needed for a climbing expedition, allowing 1 hour for every 3 miles of distance plus 1 hour for every 2000 feet of height
Word Origin for Naismith's rule
C19: named after W. W.
Naismith (1856–1935), Scottish climber, who formulated it