In order to build up a background to the relative difficulty for burning the different raw materials in cement production the solid phase reactions between SiO₂ and either CaCO₃ or BaCO₃ at the temperatures ranging 500°-800°C were studied by measuring the amount of CO₂ liberated during the reaction. Then, applying the figures so obtained into the Jander's equation for solid phase reaction the authors have tried to work out the rate constants as well as the activation energies. However, it was found out that there were many examples which failed to fit in the equation, probably, due to the additional CO₂ liberated by simple thermal dissociation of the carbonates.
On the other hand, W. E. S. Turner et al. have suggested the acceleration of thermal dissociation of CaCO₃ when it was mixed with the powder of silica or of pure gold. The same trend was confirmed to exist also in the case of BaCO₃.
Furthermore, the investigation of X-ray diffraction pattern has revealed that the reaction products of CaCO₃ and SiO₂ obtained by heating at 700°C in air for 242 hours was not wollastonite (βCaO⋅SiO₂) but larnite (β2CaO⋅SiO₂).

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In order to work out the elastic constants and their temperature dependence of high-permittivity ceramics the velocity of propagation of ultrasonic waves were studied using the rotating method which measures the angles of total reflection of insident beam by rotating the specimen. From the results the velocities of transvers and longitudinal waves and thus the elastic constants may be worked out.
The following measurements were carried out:
(1) The velocities of longitudinal and transvers waves of the frequency of 5MC in Barium Titanate were measured at the temperatures between 10° and 140°C. From the values obtained the temperature dependency of Young's modulus, Poisson's ratio, Lamé's constant, bulk modulus, and compressibility were worked out. The measurements were extended to a binary system, BaTiO₃-BaSnO₃.
(2) The same measurements were carried out with TiO₂, CaTiO₃, NiSnO₃, CuZrO₃, etc., with a result that the velocities in TiO₂ and various titanates were in the range of 7000-9000m/sec.
(3) The elastic constants of Barium Titanates showed the slight fluctuations according to the method of preparing the specimens, which probes that this simple method is accurate enough to detect such small differences.
The present method seems to be very convenient for the measurement of elastic constants of other ceramic materials whose mechanical properties are important for practical use.

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A systematic study of the colour of glasses containing iron, and both iron and manganese was carried out using the spectrophotometric method.
The base glass was a soda-lime-silica type, and the colouring agents added to the batch were rouge, copper slag, manganese dioxide, and manganese ore, all being the technical grade. Twenty four smaples containing different amount of colouring agents were subjected to the investigation. The transmission between 350 and 1100mμ were measured by a photo-electric spectrometer to represent the result by C. I. E. colour specification using mainly the chromaticy coordinates and the lightness which is familiar to glass technologists as luminous transmission.
With increasing content of total iron oxide the colour of glasses added with rouge was observed to change from blue to green.
If the partial pressure of oxygen is kept constant in the melting processes the relation
[FeO]²/[Fe₂O₃]=k/[O₂]^1/2=α(constant)
would hold, so that the ratio FeO/Fe₂O₃ is reduced with increasing amount of iron oxide. This means that the yellowish green tint of Fe₂O₃ would become stronger than the blue tint of FeO.
FeO makes the glasses darker nine times as much as Fe₂O₃, so that a glass containing FeO which is equal to 1/9 of Fe₂O₃ gives the same luminous transmission.
It was confirmed that the luminous transmission is linearly related withe FeO content of glass estimated by direct chemical analysis. This gives the possibility of estimating directly the value of FeO and Fe₂O₃ with fairly high accuracy by measuring the transmittance at a characteristic wave length. It was proved that this method may be applied to the iron contents of 0.5-2.5wt% Fe₂O₃.
The colour of the glasses added with both iron and manganese changes mainly with the change of the ratio of mangenese to iron. The transmittance curves were classified into three groups, and the authors have advanced the three chemical equations which explain satisf actly the existence of the three types of the transmittance curves.
MnO₂+3Fe₂O₃_??_2Fe₂O₃+2FeO+MnO+O₂ (for high iron ratio)
2MnO₂+2Fe₂O₃_??_2Fe₂O₃+2MnO+O₂ (for medium iron ratio)
3MnO₂+Fe₂O₃_??_Fe₂O₃+Mn₂O₃+MnO+O₂ (for low iron ratio)

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