Ferric laurate has been found to belong to neither of these two main types. This trivalent soap not only fails to exhibit the characteristic properties of the aluminium soaps, but is actually dispersed as single molecules in sufficiently dilute solutions in toluene. In stronger solutions, aggregation to the dimer occurs. Molecular weights of the soap determined by the Cottrell boiling-point method are shown in the accompanying graph. Analysis gave the iron content of the soap as 8-75 per cent (calculated for Fe(Cj2H23O2)3, 8-54 per cent), indicating that the substance obtained was mainly the neutral tri-soap. In the absence of basic hydroxyl groups, the ferric tri-soap would not be expected to polymerize like the aluminium mono- and di-soaps. The explanation of its limited aggregation compared with other metal soaps appears to lie in the increased solubilizing power of its three hydrocarbon chains, as against two or one in the divalent and mono-valent soaps. Steric hindrance to further aggregation may also be provided by the six hydrocarbon chains of the dimer.