ABSTRACT
Colebrook and White1 showed by a simple application of their transi tion law that, if the roughness was increased from say k — 0-254 mm to k = 2-54 mm in a 508 mm (20 in.) pipe, the resulting reduction in carry ing capacity would be about 25 per cent. The corresponding reduction in sectional area would, however, only be about 2 per cent. It seems reason able to conclude, therefore, that the reduction in carrying capacity is
