  This paper discusses hadron energy reconstruction for the ATLAS barrel
prototype combined calorimeter (consisting of a lead-liquid argon
electromagnetic part and an iron-scintillator hadronic part) in the framework
of the non-parametrical method. The non-parametrical method utilizes only the
known $e/h$ ratios and the electron calibration constants and does not require
the determination of any parameters by a minimization technique. Thus, this
technique lends itself to an easy use in a first level trigger. The
reconstructed mean values of the hadron energies are within $\pm 1%$ of the
true values and the fractional energy resolution is $[(58\pm3)%
/\sqrt{E}+(2.5\pm0.3)%]\oplus (1.7\pm0.2)/E$. The value of the $e/h$ ratio
obtained for the electromagnetic compartment of the combined calorimeter is
$1.74\pm0.04$ and agrees with the prediction that $e/h > 1.7$ for this
electromagnetic calorimeter. Results of a study of the longitudinal hadronic
shower development are also presented. The data have been taken in the H8 beam
line of the CERN SPS using pions of energies from 10 to 300 GeV.
