A Physical Consideration on the Nakazawa-Nakai's Density-Meter

Abstract

1. By the method of weighing given in paragraph 1), investigations were made on the physical nature of the floating sphere used in the N-N's density-meter: on the sensitivity for the density, on the effect of variation of the atmospheric pressure and on the effect of variation of the temperature of liquid. It is proved that the N-N's density-meter is of high sensitivity, which allows one to measure the difference of density 0.0001g/cm³ of liquid easily, provided that high purity of water used for dilution and the constancy of the temperature of liquid are ascertained (Paragraph 2)).
2. The density of NaCl-solution was measured by the weighing method over the temperature range 10-30°C. The density measured for NaCl-solution was found to be the same as the density of the mixture of blood and water measured by Nakai, over the temperature range 10-30°C (Paragraph 3)).
3. The method of N-N's density-meter was elucidated by a measure-ment of the density of blood, taking the thermal effects into consideration (Paragraph 4)). A reduction chart, which enables us to obtain the density at 15°C from the reading of the density-meter measured at temperatures other than 15°C. is nresented (Paragra.nh 5)).