Magnetic transition temperatures, Tc, are measured by simultaneous TM/DTA for Alumel, cobalt, nickel, and three alloys of Ni and Co. The observed values of Tc are corrected using the values for the melting temperatures of pure metals used to define the International Temperature Scale. These corrections are based on the simultaneous melting of these pure metals alongside, but separate from, the magnetic sample. Nine investigators, using a wide variety of instrumentation, have made these measurements utilizing a standard protocol. The results are compared for several heating rates. It is planned to make these same magnetic materials ultimately available to the public for calibration of temperature of their TG instruments.