The practices of powder metallurgy, in common with many of the technical arts, have grown rapidly in advance of the theory. It remains to examine the details of the process, in a scientific manner, in order to enjoy the satisfaction of deeper understanding and, perhaps, to add some useful refinements of control. Among the details that have not yet been adequately scrutinized is the process of alloying that takes place during the sintering and annealing of the pressed metal powder compacts. The coppernickel alloy series offers a simple case for study inasmuch as no intermediate phases form; the system is isomorphous—a continuous series of solid solutions. Recently the course of homogenization of these alloys was studied; a method for expressing the degree of inhomogeneity in terms of the dimensions of the microstructure and the concentration differences was proposed, and the relationships existing among the rate of homogenization, the microstructural dimensions, and the temperature of annealing were described. In order to apply these concepts to the practical problem of selecting the most favorable annealing conditions, it is necessary to know, as well, something about the relationships existing between the degree of inhomogeneity and the physical and mechanical properties of the material. The present paper presents the findings of a preliminary study of this subject and although a more complete study was interrupted by conditions arising out of the war, the incomplete observations made thus far appear to be of sufficient significance to warrant their publication at this time.