We performed tha following examination, on the physicochemical characteristics of clay in the sloping salt-field.
1) PF of clay water. 2) size distribution of particles. 3) organic matter. 4) settling volume. 5) base exchange capacity. 6) ratio on swelling and shrinkage. Consequently, the followiog results were obtained. 1) physical characteristics of clay were influencad by the humus contents and colloidal clay (2μ) 2) in the sloping sald-field the maximam hwmuscontents should be less than 2% organic carbon.

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In the previous study, it was found that in crystalizing NH₄Cl from the solution, small amount of sodium hexametaphosphate (NaP0₃) promotes the crystal growth, namelyit increases the size of the crystal and developes certain faces of the crystal. In this report, it was studied to use (NaP0₃)₆ and metal-ion simultaneously as the promoter in crystalizing of salts such as NH₄Cl, KCl, KBr and CaSO₄·₂H₂O. Result obtained: (1) Simultaneous using of (NaPO₃)₆ and Mn²⁺(or Mg²⁺) in the crystalizing of the above salts, is efficient within a certain rang of weigt ratio of those, and those quantities are comperatively small in the case of gradually cooling or other suitable condition.
(2) Obtained by the usual method of cooling the solution, NH₄CI forms as dendritical shaped crystals.But if (NaPO₃)₆ and Mn²⁺ (or Mg²⁺) are added into the solution; NH₄CI shapes as large cubes (100 plane).
(3) Similarly, from the solution including (NaP0₃)₆ and Mn²⁺, KCl or KBr crystalizes taking the form of large octahebron (111 plane), which often has 100 plane at the corner.
(4) ordinarily made by the reaetion between CaCl₂ and Na₂SO₄ solution, CaSO₄·2H₂O precipitates as fine powder. But when this reaction proceeds in SiO₂ gel,it is forms into bur-like figure.In such the case, furthermore, if the Sio₂ gel contains (NaPO₃)₆ and Mn²⁺, it appears in the shape of large transperant prism (O1O plane developed). Besides using citric acid instead of (NaP0₃)₆ is available, but it's shape becomes semitransperant irregular3n prism.

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Rapid methods for the drtermination of small amounts of chlorine in the bromine was investigated, and the following two procedures were developetd.
1) Direct method; A bromine sample was reduced to bromide with hydrogen peroxide or sodium sulfite. Then the chlorine in the bromine was reduced to chloride. Adding a small excess of potassium bromate to the solution, the bromide was oxidized to bromine, and it was extracted with carbon tetrachloride. The chloride remaining in the aqueous layer was determnied by the Volhard method. The presence of a large amount of potaseium bromate caused errortical results.
2) Indirect method; Potassium bromate was added to the reduced sample solution, and almost all bromide was oxidized. The bromine was extracted with carbon tetrachloride and the aqueous layer was made up to the definite volume. The solution was divided into two aliquots. The sum of bromide and chloride was determined by Volhald method in an aliquot. The bromide was determined in the other, treating the solution with sodium hypochlorite and titrating the bromate iodometrically. The accurate result was obtained, when the molar ratio of bromide to chloride ion was smaller than 2.
From 0.2 to 1 percent of chlorine in bromine could be de termined accurately by the above procedures.

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Magnesium hydroxide can be prepared by treating desulfated bittern with milk of lime, caustic soda solution etc. it is obtained usually in a colloidal- like state as other metal hydoxides. To increase the particle size is, therefore, the most important requirement of the preparation. it is recognized that in the so-called continuous type of reaction, the pH of the solution varies considerably about 100% equivalet accompanying with great difference in the particle size, and the average size reaches more than 30, in the stable continuous state when the solution is kept strictly on the optimum pH The fact may be explained briefly by theory of crystal growth, and it can be concluded that the most rational method of the preparation is to keep the solution the optimum pH in the socalled continuous type of reaction.

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Calculation of working temperature differences, steam consumption and evaporation of each pan is performed for evaporation of salt field brine (before saturation) with quadruple effect vacuum evaporators. Rate of evaporation per unit heating surface is about 20% greater in seed addition to the 1st. pan (thus using this effect for concentration) and about 16% greater in seed addition to the 4 th pan than in feeding brine into bittern (parallel feed) total evaporation per unit steam consumption in seed addition to the 4 th pan is nearly equal to the value in feeding brine into bittern. butthe value in seed addition to the 1 st pan is much smaller, Taking into account scale is apt fo form in seed addition to the 1st. pan it seems that seed addition to the 4 th pan is preferable.

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