抄録
Some of the thermometric fixed points between 20°C and 100°C are studied. The freezing point of commercial (extra pure) naphthalene is found to be easily realized, with a reproducibility of ±0.01deg, by simple cooling in air of cells containing molten naphthalene and to have a plateau temperature of 79.72°C (Int. 1948). The triple point of naphthalene is also reproducible within ±0.01deg.
The triple point of diphenylether, purified repeatedly by distillation and fractional freezing, reveals a reproducibility of ±0.001deg and an equilibrium temperature of 26.870°C (Int. 1948), if it is realized by a method of cooling from inside of cells containing liquid diphenylether.
By means of these diphenylether cells, four temperature scales maintained independently in National Research Laboratory of Metrology, Japan Meteorological Agency, a thermometer manufacturer (Hokushin Electric Works, Ltd.) and a chemical plant (Ajinomoto Co., Inc.) are compared each other. Sufficient agreement among them, so far as the desired accuracy is concerned, is thus confirmed.
