A report of the initial stages of an investigation of the intrinsic properties of dilute alloys of iron is given. Methods of determining spontaneous magnetization and Curie temperatures with precision of one part in 30 000 are discussed. The results for Fe‐Ti alloys are singled out for attention. The decrease of spontaneous magnetization at a rate of more than 1.6 times that of simple dilution implies either a negative moment on the Ti atoms or more probably that the occupation of states contributing to the moment on the iron is decreased by the addition of Ti. The increase in the Curie temperature at a rate of 3.7°C per atomic percent Ti is discussed on the basis of the Bethe‐Slater curve of exchange interaction as a function of atomic separation.