  The cosmic ray flux measured by the Telescope Array Low Energy Extension
(TALE) exhibits three spectral features: the knee, the dip in the $10^{16}$ eV
decade, and the second knee. Here the spectrum has been measured for the first
time using fluorescence telescopes, which provide a calorimetric,
model-independent result. The spectrum appears to be a rigidity-dependent
cutoff sequence, where the knee is made by the hydrogen and helium portions of
the composition, the dip comes from the reduction in composition from helium to
metals, the rise to the second knee occurs due to intermediate range nuclei,
and the second knee is the iron knee.
