1967 年 36 巻 11 号 p. 879-886
The density of a liquid can be determined by the pressure difference at two points of known height difference in the liquid. This paper is concerned with two hydrometric methods by this principle. The pressure difference is measured by an apparatus with two equal bellows, which are connected by rods, keeping the bellows at a constant distance. The first method is to measure the pressure difference of two points directly. The second method is to measure the pressure difference of two points by liquid purge. These hydrometric methods make it possible to measure continually the density of liquid and is applicable to industrial practice.