Around the turn of the century, when Horton was conducting his famous
weir experiments, in the same laboratory Saph and Schoder recorded som
e pipe flow data that were to have a profound impact on the evolution
of turbulent boundary layer theory. These, by way of Blasius's dimensi
onal analysis, ultimately led Prandtl to derive the 1/7 power equation
for the velocity profile; this in turn was the precursor of the logar
ithmic equation. the cornerstone of all present-day similarity formula
tions for the atmospheric boundary layer.