“…Nevertheless, although correction in this way is possible, experiments in which residues are formed and corrections applied are regarded as less reliable than those in which nitrobenzene was used as reference solvent. In most cases, where residues are formed (Augood, 1952;Augood, Hey and Williams, 1952), it was found that, to a first approximation, the X-and Y-diphenyls were removed by further phenylation in the same ratio as that in which they were formed by the phenylation of C 6 H 5 X and C 6 H 5 Y, that is:…”