Ceramic bodies having the composition of 85 BaTiO₃-15 PbSnO₃ (in mols) were prepared by the following two processes: (A) A mixture of barium titanate and lead stannate was formed and fired at 1320°C for 20 min.. The titanate and the stannate used were previously prepared by heating a mixture of BaCO₃ and TiO₂ at 1200°C for 30 min. and of SnO₂ and Pb₃O₄ at 1100°C for 20 min. respectively. (B) A mixture of BaCO₃, TiO₂, SnO₂ and Pb₃O₄ was formed and fired first at 1100°C for 20 min. and then at 1320°C for 20 min.. All the raw materials used were of high purity. During firing, in both processes, the specimens were embedded in the powder having the same composition as the specimens for suppressing evaporation of PbO from the specimens.
Dielectric measurements and X-ray analysis of the fired bodies clearly showed the significant differences in their properties between the bodies prepared by the two processes: For the bodies prepared by (A) the dielectric constant was 7000 at the Curie point, 44°C, its variation with temperature being relatively little, i.e., less than 4% in the temperature range 34°C to 52°C. For the bodies prepared by (B) the dielectric constant was 6000 at the Curie point, 87°C, its variation being fairly sharp i.e., 4% in the temperature range 82°C to 93°C (Fig. 9). Lattice constants for every spacing had the same value, i.e., 4.025 Å, whereas they were scattered between 3.996 Å and 4.024 Å for the bodies prepared by (B) (Table 3).

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The mean particle size of several kinds of powders, i.e., anatase, rutile, calcite, silica gel and carbon black, was determined from the specific surface measured by heat of wetting method, so-called the “absolute method” devised by Harkins and Jura in 1944. The results were compared with the data from adsorption method and electronmicroscopy method.
The values from the heat of wetting method, using water as immersion liquid, showed a fairly good agreement with that from N₂ adsorption method. In the case of colloidal silica the heat of wetting measurement at saturated vapor pressure may be unsuitable for the estimation of specific surface, because of intense capillary condensation. However, there is prospect for obtaining reasonable data at the relative vapor pressure of 0.4-0.6.
The heat of wetting method, having little theoretical assumption, is quite ingenious and moreover it is considerably simple and reproducible. It is seen that the capillary condensation is significant problem for the application of this method to the fine powders in wide fields.

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The authors have tried to use calcium sulphite-a low price byproduct of sulphulic acid industry-as substitution of gypsum for portland cement. The substitution resulted in an increase in strength and decrease in the construction of the cement.
In the present paper the investigation of the reaction mechanism between cement clinker and calcium sulphite was carried out using X-ray diffraction, differential thermal analysis and measurement of heat of formation. The results obtained may be summarized as follows:
(1) In the existence of free lime tricalcium alminate hydrated rapidly to form 4CaO⋅Al₂O₃⋅13H₂O, 3CaO⋅Al₂O₃⋅8-12H₂O as well as 3CaO⋅Al₂O₃⋅6H₂O and after ten weeks the formation of 3CaO⋅Al₂O₃⋅8-12H₂O remarkably increased. When free lime was added jointly with gypsum 3CaO⋅Al₂O₃ hydrated to form gypsum bacillus, 3CaO⋅Al₂O₃⋅CaSO₄⋅31H₂O, and 4CaO⋅Al₂O₃⋅13H₂O at the first stage, and then decrease of gypsum bacillus and increase of 4CaO⋅Al₂O₃⋅13H₂O followed. The addition of CaSO₃⋅1/2H₂O and lime resulted in the formation of calcium sulphoaluminate bacillus, 3CaO⋅Al₂O₃⋅CaSO₃⋅7H₂O, and 4CaO⋅Al₂O₃⋅13H₂O.
(2) The calcium sulphoaluminate bacillus was formed by the reaction of 1mol CaSO₃⋅1/2H₂O with 1mol 3 CaO⋅Al₂O₃ at 110°C in the atmosphere containing saturated steam, but it decomposed at 140°C.
(3) The values 45.7, 7.15 and 1.34kcal/mol were given for the heat of formation of 3CaO⋅Al₂O₃⋅6H₂O, 3CaO⋅Al₂O₃⋅CaSO₃⋅7H₂O and gypsum bacillus respectively.
(4) In the hydration of synthetic 4CaO⋅Al₂O₃⋅Fe₂O₃ we found the same hydrated compounds as the case of 3CaO⋅Al₂O₃.

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The forsterite porcelains were prepared from mixtures of Mg(OH)₂ and SiO₂ (α-quartz), both of high purity, in the molar ratio of 2:1.2 with and without the admixtures of Kaolin and BaCO₃. The mixtures were heated at the velocity of 200°C/hr, kept at various temperatures for 15min., and cooled rapidly in air.
X-ray diffraction analysis and the microscopic observation were made for the identification of minerals formed in the fired specimens. For the specimen without the admixtures the formation of forsterite, which was exothermic, was found to set in at about 1100°C and complete at about 1400°C. The formation of protoenstatite began from 1280°C by the secondary reaction of 2MgO⋅SiO₂ and SiO₂. In the specimen with the addition of 5% Kaolin (PSF-O) which sintered at 1460-1500°C were found forserite, protoenstatite, clinoenstatite, α-quartz, and periclase. In the specimen with the addition of 5% Kaolin and 10% BaCO₃ (PSF-B) which sintered at 1300-1420°C were found forsterite, BaO⋅2SiO₂, 2BaO⋅3SiO₂, and BaO glass. The dielectric losses at 1Mc/s of both specimens, PSF-O and PSF-B, were alike and very small, whereas the value at 10, 000Mc/s of PSF-O was smaller than that of PSF-B.
For the practical purpose, the forserite porcelains were also made from sea water magnesia and silicious stone instead of from pure Mg(OH)₂ and α-quartz. The base composition was the same as above, but in this case the admixtures were BaCO₃, ZnO, and CaO⋅2B₂O₃ glass. They were added respectively to the base batch by 5 and 10% by weight. The batches without the admixtures were also prepared. The seven kinds of batches thus prepared were calcined respectively until the forsterite forming reaction was completed. They were ground and mixed with 5% Kaolin, and again fired at various temperatures. These fired specimens were examined for their thermal, mechanical, and electrical properties. It was found that the admixtures such as BaCO₃, ZnO, and CaO⋅2B₂O₃ glass had a favorable effect of reducing the dielectric loss of the fired specimen; especially the addition of BaCO₃ was most effective. The results of the test of refiring in H₂ atmosphere at 1300°C showed, however, that these admixtures in the fired specimens were easy to be reduced and evaporate. Therefore, as the vacum tube the forsterite porcelain without the admixture was recommended.

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The specific resistance (ρ) at 40°C of V₂O₅-P₂O₅-BaO glasses was found to be affected significantly by the chemical composition and the melting condition; ρ changed with the mole ratio of BaO/P₂O₅ even when the V₂O₅ content was kept constant. The ρ v. s. BaO/P₂O₅ curves with a constant V₂O₅ content, in which the characteristic minimum occured, shifted towards the higher value of BaO/P₂O₅ when the melting temperature of the glasses was raised.
A large amount of low valency vanadium which was considered to be V⁴⁺, was found in the glasses. Its amount decreased with increasing BaO/P₂O₅ and the total amount of vanadium present in the glass, and moreover increased with increase in the melting temperature of the glass. The curve relating ρ with [V⁴⁺]/ [total vanadium] had also a minimum. It was however independent of BaO/P₂O₅ and of the melting temperature of the glasses.
Based on the above mentioned results the authors discussed the mechanism of the electrical conduction of the vanadium containing glasses pointing out that it closely resembled that of magnetite. They concluded that the conduction of the glasses was probably due to the valency exchange between V⁴⁺ and V⁵⁺.

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