“…The thermometers that were investigated by Hoge and Brickwedde showed a spread of 7 mK between 190 and 0 C, and spread of 1.3 mK between 0 and 100 C. The six thermometers measured between 100 and 444 C had a maximum spread of 12 mK. Data which would indicate the spread of interpolated values of temperature on the IPTS 68 below C due to the variations in presently acceptable platinum wire is sparse and inadequate [11,36,44]. On the basis of existing data, Bedford and Ma [9] estimated that the IPTS-68 is reproducible to 3 mK between 14 and 20 K, 1 mK between 20 and 54 K, it 2 mK between 54 and 90 K, and 5 mK between 90 and 273 K. It should be pointed out that, in addition to unaccounted for variations in the platinum wire, a spread in the temperature values may also arise from incomplete definitions of the materials that define fixed points (e.g., their isotopic composition).…”