Discussion on P.G.H. Allen, O. Szpiro and M.W. Collins ' Prediction Methods for Entry Length Heat Transfer by Combined Laminar Convection in Horizontal Tubes '. This discussion relates to paper No.33 published in Volume 196, pages 409-415 (Proc. Instn. Mech. Engrs., 196, 1982; 409-415)Proc. Instn. Mech. Engrs., 196, 1982; S55-S59.