In 1934 Hume-Rothery, Mabbott and Channel-Evans discussed the factors affecting the formation of primary solid solutions in silver and copper, and concluded that the predominant factors were the atomic diameters and valencies of the solvent and solute elements. In a later paper (Hume-Rothery and Raynor 1938) it was shown that the same considerations applied to the formation of solid solutions in magnesium, provided that due allowance was made for the highly electropositive nature of this metal. In the case of copper and silver alloys, where general valency effects are marked (Hume-Rothery et al . 1934), Hume-Rothery, Lewin and Reynolds (1936) carried out an investigation of the mean lattice spacings of primary solid solutions of cadmium, indium, tin and antimony in silver, and of zinc, gallium and germanium in copper. It was found that, to a high degree of accuracy, equal percentages of cadmium, indium, tin and anti­mony expanded the lattice of silver by amounts proportional to 2 : 3 : 4 : 6 respectively. Zinc, gallium and germanium in equal atomic concentration in copper expanded the copper lattice by amounts proportional to 3 : 4 : 4.8. These factors have been confirmed by Owen and Roberts (1939) and shown also to apply at high temperatures. The factor for germanium in copper was, however, given as 5.

The lattice spacings of the primary solid solutions of silver, cadmium and indium in magnesium. (1940). Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, 174(959), 457–471.