Effects of recent knowledge of atomic constants and of humidity on the calibrations of the National Bureau of Standards thermal-radiation standards

Th e National Bureau of Standards the rm a l-rad iation standards, as established and maintained since 1913, are based prim a ril y upon t he emission of a blackbody, using the Stefan-Bo ltzmann consta nt of total radiation u = 5. 70 X 10-12 watt/ ( cm2 deg) .