SIR CLAUDE INGLIS, in. his letter published in Nature of October 19, p. 552, remarks that my formulae for alluvial flow are based on two fundamental relationships. It would be more correct to state that two independent fundamental equations are necessary to a complete solution, and that each of these equations consists of an empirical correlation of dimensionless numbers or 'arguments', derived from the essential variables. Dr. White has produced a partial solution, which effectively ignores the Reynolds number. The following solution appears to be complete.