The elemental constitution of organisms, rocks and metals was found to have linear relations to that of the earth crust.Logarithms of the ratios of sample concentration to those of seawater were used as ordinate, Y=log (C_SA/C_WA), and those of the earth crust as abscissa, X=log (C_EC/C_SW).Regression lines, Y=A+BX, describe “omnipresence of elements” semiquantitatively.These samples were classined into 3 groups according to the inclination of the regression lines, B: i) B=1 (0.8 to 1.02);rocks, oxides, carbonate, phosphate, coal, ii) B=0.5 (0.4 to 0.7);organisms, metals, river water, petroleum, iii) B=0;seawater.The author used two parallel lines to the regression line instead of curves which were used usually, to express the 90% confidence interval. The elemental constitution of the samples composed of cells: microorganisms, plants, animals, muscle, bone, liver, was described by only one regression line.The inclination of regression lines changed in line with chemical reactions;e.g.values of B were decreased as much as 1 or 0.5 by dissolution, where seawater or river water formed from rocks, decreased ca by 0.5 by metal formation from oxide, and they were incresed by 1 or 0.5 by precipitation, where sediments or organisms formed from seawater.

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The adsorptive properties of molybdenum (Mo) and vanadium (V) in sea water on manganese hydroxide oxide (MnOOH) were investigated by batch method. The Mo uptake on MnOOH was found to depend on both the pH and the temperature of adsorption. In the region from pH 6 to 10, the logarithm of the distribution coefficient (log K_d) of Mo showed a linear decrease when pH increased. The slope of the linear was -1. The Mo uptake decreased when the adsorption temperature rose from 5 to 50°C. These results suggested that Mo was adsorbed on MnOOH by anion exchange mechanism. The V uptake by MnOOH was constant without depending on the pH in the region from pH 5 to 9, and it did not depend on the adsorption temperature, either. The adsorption isotherms at pH 8 followed the Freundlich's relationship. The equilibrium adsorptive capacities from sea water were 15 and 160 μg·g^-1 for Mo and V, respectively. MnOOH was considered to be advantageous for recovering V from sea water.

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Adherent dirt on ion exchange membrane for salt-making was studied to conduct the measurement of the adhesion quantity and classification analysis of the composite, and the proposed procedure was applied to the survey of the adherent dirt of membrane at salt-making plants. The adherent dirt was collected by washing the membrane with a plastic sponge and small amount of filtrated seawater, and the most part of suspended water collected from the membrane was settled, filtered, and washed by distilled water, and dried and weighed for measuring the total weight of the adherent dirt. A part of the suspended water was measured to determine the volume after centrifugation, and the precipitate was dried and weighed for measuring the specific volume. Thickness of the adherent dirt on the membrane was estimated from the total weight, the specific volume, and the area of the membrane.
On the classification analysis, ignition loss in dried matter was determined at first, and its ignition residue was dissolved into hot and dilute sulfuric acid. After separation of filtrate and precipitate by filtration with membrane filter, the precipitate was weighed. Qualitative analysis of inorganic elements in the filtrate was carried out by ICP analyser, and main elements were deter-mined by the same instrument. The ignition loss was almost organic matter. Either weight of the precipitate after dissolution by acid or the sum of contents of silicate and aluminum from determination by ICP was almost earth and sand. Ferric matter was estimated by ferric hydroxide obtained from Fe content. The composition of the adherent dirt was classified as organic matter, ferric matter, earth and sand, and others.
The survery at four salt-making plants was carried out in the washing process of membrane. The results were as follows; Weight of adherent dirt: 0.1-1.5 g-dry matter/m² (av. 12g/m²), estimated thickness of adherent dirt: 2-23 μm (ay. 8 μm), adhesion rate: 2-20 mg-dry matter/m² (ay. 12 mg/m² dry), 0.03-0.23 μm/day (ay. 0.08 μm/day), organic matter: 38-79% in dry matter (ay. 61%), ferric matter: 2-12% in dry matter (ay. 6%), earth and sand: 15-53% in dry matter (ay. 31%), others: 0-4% (ay. 3%).
The inorganic elements detected were as follows; +++: Mg, Al, Fe, ++: Si, Ti,: Mn, ±: Ba, B. And an average content in acid soluble matter was as follows; Fe: 3.3%, Mn: 0.09%, Al: 2.8%, Si: 1.2%, Ti: 0.05%, and Mg: 0.6% as content in dry matter respectively.

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In the previous papers, the quality of solar salts of various countries was studied from the amount of impurities and the crystal-form. In this paper, the author studied the relation between the quality of Thai solar salts and the composition of mother liquid in both concentrating and crystallizing ponds. And the following results were obtained:
1. The amount of impurities of Thai solar salt was much more than those of other countries.
2. Crystals of Thai solar salt consisted of 2-3 mm unit-crystals, which weakly attached to each other. And they easily separated from each other when they were crushed by hand.
3. The chemical composition of mother liquids in the crystallizing ponds was 20-40 Mg mol/1,000 mol H₂O and was rich in magnesium sulfate as compared with the one in the normal con-centrating process of sea water.
4. The author has estimated as follows how Thai salt comes to contain lots of impurities: Thai solar salt crystallized in the mother liquid of high magnesium concentration with high crystallizing rate. Those conditions cause the salt to have many cavities in crystals as well as much room surrounded by small unit-crystals. Both the cavities and rooms were filled with mother liquid containing many impurities.

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