The sulphate content of cements was determined by an anion exchange resin method. The sulphate ion was converted to chloride ion using Amberlite IRA-400. The chloride ion was titrated by the potentiometry. The results agreed with the results of the barium sulphate method, and were obtained in 2 or 3 hours.

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By use of the Burgers' model, Visco-elastic property of clay mass is discussed from a theoretical point of view, and substantiated a new theory to a mechanism of plasticity.

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Various kinds of refractories, such as chromite, chromite-magnesia, magnesia-chromite, forsterite, alumina, magnesia, spinel, dolomite, etc., were collected and tested for making calcium-magnesium phosphatic fertilizers. The experiments showed that refractories for fused phosphatic fertilizers must be basic and very compact. The present authors tried to make compact magnesian refractories by adding alumina and lime. In this case, molectlar ratio CaO/Al₂O₃ must be larger than 3:1 or smaller than 3:5. Magnesite, bauxite and dolomite were mixed in such ratio 3:1:0, 2.7:1:0.3 or 2.5:0.1:0.4 and fired at 1450°C for 1 hour. The physical properties of these prepared refractory specimens were fully examined, and also the corrosion test by the fused phosphatic fertilizer was carried out with good results.

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The purpose of this paper is to study the behaviour of melting of coarse quartz gains in feldspathic fusions, one of the most important reactions occurring in porcelain bodies during firing. Small tablets consisting of 97% fine ground potash-or soda-feldspar and 3% definitely sized quartz graines (mean intersection diameter, 150.4 μ) were prepared. Some of them were fired at 1150°-1450°C with different rates of 60°, 120°, and 180°C per hr., and the others were maintained for 0.5 hr. -4hr. at 1300°, 1330°, 1350°, or 1400°C in anelectric furnace, and thence abruptly cooled in air. Intersection diameters of 100-300survived quartz grains scattered within glassy phases were measured through thin sections by polarization microscope, and, then, the mean values were calculated. Fromthe values obtained, melting behaviour of quartz grains in feldspathic fusions was inferred as follows:
(1) The dissolution of quartz grains into feldspathic fusions was markedly slower than had been usually considered. In general, coarse quartz grains were more easily dissolved in potash-feldspathic fusions than in soda-feldspathic ones.
(2) Jander's equation was applied approximately to the dissolution of quartz grains in feldspathic fusions, as treated in this paper.
(3) It seems that Arrhenius' equation did not strictly hold for the dissolution of quartz grains into the feldspathic fusions.
(4) The following relationship was obtained between firing temperatures and dissolution of quartz grains in the fusions:
1-(1-x)^1/3=Be^-C/T
where x: reaction ratio in volume, T: firing temperature, (°K), B and C: constants.
(5) In the system soda-feldspar-quartz, it was found that the dissolution behaviour of quartz grains might show a marked change at some temperatures within 1250°-1300°C
It was also certified that the microscopical method was very advantageous and precise for the quantitative study on the dissolution of solid crystalline grains into fusion.

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