The absolute Seebeck coefficients of the remain- ing metals (Au, Pd, Pt, Rh and Ir) are given in Fig. 1. Any one of the elements Au, Rh and Ir, which have similar coefficients, may be used with either Pt or Pd to form a practical thermocouple, as may Pt with Pd. These combinations have usefully large relative coefficients--about 6~tVK -1 at 0°C to ~20~tVK -1 at 1000°C - except Au, Rh or Ir versus Pd which would have