In this study, amounts of titanium contained in sea water, biomaterials and sediments were determined by a method using tiron (disodium-1, 2-dihydroxybenzene-3, 5-disulfonate).
Ferric iron was added to slightly acidified sample solution as a carrier for titanium, and pH was adjusted to 8.5-9.5 with ammonia. Ferric hydroxide was filtered and dissolved in sulfuric acid. The major portion of iron was removed by mercury cathode electrolysis, and then the absorbance of titanium-tiron complex formed at pH 4 in the presence of EDTA, was measured at 420 mμ.
After analyzing sea water and lake water samples, several kinds of biomaterials such as seaweed or shellfish, and sediments, the following results were obtained: The content of titanium in sea water amounted to approximately 2μg/l, and that in several kinds of shellfishes and seaweeds amounted to 2.5-6.9×10^-2% and 2.5-6.5×10^-8% in ash samples, respectively. The titanium content in marine sediments was of the order of 10^-1%. In general, the sea samples contained less amount of titanium as compared with the similar land samples.

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It is feared that heavy metals contained in sea water become obstacles to the manufacturing of salt, and besides those contained in common salt are no good for the reasons of food sanitation. There, forethe author conducted a study as to how to remove copper, zinc and lead from sea water and salt by means of filtration and coprecipitation, and obtained to following results:
(1) Judging from the results obtained by measuring the solubilities of these heavy metals in sea water, it is difficult to remove them by filtration. However, when common salt is made from the sea water saturated by these metals, the content of these impurities is supposed to amount to less than 10 pp. The salt containing a great amount of these metals can be refined to the extent of less than 15 ppm by disolution, filtration and recrystalization at pH 9.
(2) Those metals contained in sea water can be removed by coprecipitating them at the pH of over 7 with the floc of ferric hydroxide, aluminium hydroxide or magnesium hydroxide. To any concentration of heavy metals in sea water, the treatment with the floc amounting to less than 12mg/l of ferric ion or aluminium ion was sufficient for coprecipitation. As to the treatment with magnesium hydroxide, addition of 5 ml/l sodium hydroxide solution (1 N) was sufficient for the coprecipitation. In all cases, the velocity of coprecipitation was quick, and the effects of temperature were insignificant.
(3) The coprecipitation method with ferric hydroside, aluminium hydroxide or magnesium hydroxide was also effective for the removal of copper, zinc and lead in the common salt solution of high concentration.

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For the purpose of observing the flow of brine in the standard type evaporator, we made section patterns (scale: 1/2 and 1/4) which enabled us to examine the flow of brine in the evaporator. By suspending the fine particles in fresh water at normal temperature, the stream line and the velocity were measured with photographs taken with a stroboscopic camera. The flow of brine in the evaporator was observed by measuring the static pressure through many pressure taps of the pattern. From the stream line and static pressure thus observed, we were able to illustrate the relation between the bottom shape of the evaporator, the level of liquid and the head loss. It was found that the dish-like bottom of the evaporator was of an ideal shape for an evaporator. On the other hand, it was recognized that the distribution of the solid fractions of liquid in the standard type evaporator with an area of 15m² coincided with that of the velocities in the pattern. We studied the similarity of the flow of brine in the patterns with the different reduced scales by the turburence intensity and the turburence Reynold's number, on the basis of the results obtained.

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The heat transfer in a common salt bed is closely connected with the caking tendency of salt. It was found that when the salt bed is regarded homogeneous in macro, the general theory of heat conduction is applicable to it (the influence of heat convection and radiation was negligible). Accordingly, it is possible to theoretically estimate the change of temperature in the salt bed by determining the thermal diffusivity. Therefore, the relation between the moisture and the thermal diffusivity of many kinds of samples was studied.
A pattern was devised to illustrate the contacts among crystals, and it consisted of two spheres of an equal size contacting at the distance of l and drawing the surface liquid around the contacting point by the surface tension. The results of discussion obtained well agreed with the experimental results. The distance l is considered to correspond to the coarseness of the crystal surface in micro, and it may be regarded as one of the characteristics of salt.

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Experiments were conducted on the physical and chemical properties of U. S. made salt such as the color, the shape of particles, the distribution of particle size, the apparent specific gravity, the angle of repose, the velocity of moisture adsorption and solution, and the chemical composition. The following are the results obtained:
1) In the U. S. A., there are many kinds of salts each of which is suited to its own purpose. They are found to greatly differ in physical and chemical properties from the another according to the purpose.
2) U. S. made table salt is extremely good in the free-flowing quality as compared with domestic salt, and sodium silico alminate is found to have been used in it as an additive agent.
3) In general, U. S. made salt contains very small amount of calcium and magnesium salts, and therefore the content of sodium chloride is greater than that of the domestic salt.

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