Test of High-pTScaling from Cosmic-Ray Interactions up to 400 TeV

The rate of subcores in cosmic-ray air showers has been measured near sea level with a close-packed 35-${\mathrm{m}}^2$ array of spark chambers at Leeds. Auxiliary experiments demonstrate that our transition effects are negligible. The rate of subcores versus shower size is translated into the rate of high-$p_T$ events versus energy of the interacting hadron. Comparison with calculations of Halzen favors ${p_T}^{-4\mathrm{}}$ over ${p_T}^{-8\mathrm{}}$ scaling. The highest energy bin is centered on 350 TeV.