1983 年 52 巻 7 号 p. 619-625
A sedimentation-potential-generating apparatus has been improved to realize precise measurement. From the theoretical discussion, it is found that the total mass of the moving parts consisting of a sample solution, its measuring container, a copper electromagnetic shield made in the form of a thin cylinder, a connecting rod, and the intrinsic mass of the moving parts must be decreased, and that the mass of the sample solution should be equal to the total mass of the remaining moving parts. Therefore, the apparatus is so designed that the shield is divided into two parts, a moving shield and a fixed one whereby the total shield mass is lightened, and the measuring container is also lightened. The apparatus has been applied to measure the sedimentation potentials of twenty alkali halide solutions. The results show that the rate of change of the sedimentation coefficient due to atomic weight is approximately proportional to the transport number.