To improve the spectrophotometric method for the determination of traces of vanadium in crude salt, a study was conducted on the sodium diphenylaminesulfonate method already reported by Hirano and his co-workers.
The intensity of color varied according to the manner of the developing process. A further study was undertaken by varying the manner of adding reagents, and some suggestions were given to obtain the reproducible results.

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With a view to preventing scale from adhering to the heating surface of a brine preheater, we carried out a fundamental study concerning the possible effects of a minute quantity of sodium hexametaphosphate added to sea water or brine, on the corrosion of mild steel and copper. We obtained the following results from the above study:
1. As to effects of temperatures, an anti-corrosion effect was recognized within the range of 25-100°C when a minute quantity (30 p.p.m.) of sodium hexametaphosphate was added in case of mild steel. In case of copper, however, the effect was less, and the corrosion was even promoted in the sea water of temperatures ranging from 25°C to 50°C.
2. As to effects of the quantity of sodium hexametaphosphate, the agent proved effective in every quantity within the range of 2-200 p.p.m. in case of mild steel. In case of copper, however, it was effective only when over 30p.p.m. of the agent was added to sea water or when over 15 ppm to brine.
3. It was found that the proper quantity of sodium hexametaphosphate effective to the anticorrosion did not coincide with that effective to the anti-scaling.

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As magnesium bleaching powder (MBP) prepared through electrolytic process contains some moisture, it can often decompose itself giving out some chloric smell when dried at a fairly high temperature; even at about 100°C. For the purpose of examining the thermal stability of MBP, the author measured the weight loss of MBP, the content of available chlorine and the decomposing rate, at several different temperatures ranging from 100°C to 500°C.
When MBP was dried at 100°C, the content of available chlorine increased by approximately 0.8-1.4%, but as compared with the original, the whole content showed a decline with its decomposing rate. When dried at 100°C for one or two hours, the decomposing rate of MBP was only less than 1% which caused no hindrance to the drying of MBP. On the other hand, when wet MBP (for example, 21% moisture is contained) was dried at 100°C, its decomposing rate reached approximately 3%. This fact shows that the presence of some moisture is unfavorable.
The decomposition of MBP became more and more remarkable as the heating temperature rose higher than 150°C. When MBP was dried at the temperatures between 300°C and 350°C, it was completely decomposed into MgO of high purity.

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It was mentioned in the previous report (1) that magnesium bleaching powder (MBP) had a thermal stability against the heating and drying at normal temperatures. The present report describes the results of a thermogravimetric analysis, which was carried out between the temperatures of 50°C and 440°C by using a thermobalance to determine the temperature at which MBP is decomposed.
The most favorable rate of raising temperatures for the decomposition of MBP was shown to be 100°C per hour. The thermal decomposition curve indicated that there was a great loss in its weight when MBP was heated at the temperatures between 300°C and 350°C. Accordingly, these temperatures were decided as the decomposing temperatures of magnesium bleaching powder. However, as for MBP which contains much magnesium hydroxide and has the chemical formula of Mg(ClO)OH·2Mg(OH)₂ made through the electrolysis under the weakly acidic condition, the upper limit of thermal decomposition temperature was 410°C.
It was also found that the decomposition of MBP gradually began even at 100°C-290°C, losing not only its moisture but also a part of its available chlorine.
When MBP was completely decomposed, the weight loss was approximately 44.3%-45.3%.

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After six kinds of cations (H⁺, K⁺, NH₄⁺, Na⁺, Ca⁺⁺ and Mg⁺⁺) in their chloride solution were adsorbed by three kinds of clay-soils (Kaolinite, Allophane and Montmorillonite) tests were conducted on the following physical properties of these soils: 1) grain size distribution, 2) specific gravity, 3) settling volume in water, 4) coefficient of permeability, 5) plastic range, 6) soil suction, 7) water adsorption and surface area, and 8) defacement.
The property of soil changed under the different conditions of moisture. An investigation was conducted in general on the influence of the adsorbed ions upon the thickness and strength of the water-film surrounding a soil particle. It was carried out ranging from the saturation of the soil moisture to the desication.
1) The properties of the three kinds of clay-soils remarkably differed from one another.
2) The influence of the adsorbed ions was the most remarkable in the case of Montmorillonite, followed by Kaolinite. Very little influence was observed in the case of Allophane.
3) The influence proved to be the most remarkable within the range of pF 0-3.
4) As to Montmorillonite, Na-soil showed its singularity to all the soil properties and had remarkable hydrophilic properties.
5) As for Kaolinite, Na, NH₄ and K-soil showed a considerable thixotropy at L. L.
6) The range of the pF of soils corresponded to P. L. and L. L. was rather narrow regardless of the kind of ion.
7) The results of the water-adsorption test were in conformity with the B. E. T, equation, and the surface area of the soil was 5-8m²/g on Kaolinite, 180-210m²/g on Allophane, and 130-220m²/g on Montmorillonite.

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A functional test was conducted with panels on the taste of the solution of common salt, and the following results were obtained.
1. As the concentration of the salt solution rose, the difference limen became greater. The relationship between the two was proportional. In the solution of fixed concentration, the lower difference limen was smaller than the upper one.
2. It was found that the stimulus limen of the salt solution was 0.113%.
3. The test showed that women were a little more sensitive than men to the taste of salt solution.

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