The firing range of petalite ceramics can be extended markedly by the addition of powdered lithia glass (Li₂O 10.7, MgO 8.9, Al₂O₃ 8.9, SiO₂ 71.5wt. %) to petalite powders in a weight ratio of 1:9 (M. Tashiro and T. Maki, J. Ceram. Assoc. Japan, 70, 8 (1962); M. Tashiro and T. Maki, J. Ceram. Assoc. Japan, 71, 65 (1963); T. Maki and M. Tashiro, J. Ceram. Assoc. Japan, 71, 196 (1963)). In the present study, slip preparation most feasible for this nonplastic mixture was studied. The most stable slip composition determined was petalite 90, lithia glass 10, bentonite 5, and carboxymethyl cellulose (CMC) 0.02 in weight ratio. The raw materials were ball-milled in water to the fineness of almost less than 5μ in diameter. The optimum water content was 35% (wt.) of the wet base. When the bentonite content exceeded the above value, slip-cast specimens shrunk more than 27% in volume on firing. CMC was effective not only as a floating agent but for increasing the mechanical strength of dried slip-cast specimens. The modulus of rupture of 900kg/cm² was attained in the slip-cast specimen fired at 1250°C for one hour.

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Recently electric boosting technique using molybdenum electrode is often applied in glass melting. In this paper, studies on effects of temperature and composition of glasses on corrosion of molybdenum are reported.
In the first experiment molybdenum test pieces were immersed in various kinds of molten glasses, namely, borosilicate, aluminosilicate, soda-lime-magnesia, barium or lead glasses for 50 hours at 1400°C, and in the second, effects of refining agents such as As₂O₃, Na₂SO₄ and Sb₂O₃ were examined by 50 hours' soaking at temperatures from 1100° to 1500°C.
Visual observation of molybdenum test pieces and glasses after the corrosion test and determination of weight loss of molybdenum showed that;
1) Weight loss of molybdenum increased with rising the soak temperature.
2) Weight loss of molybdenum increased distinctly with the amount of As₂O₃ and slightly with Na₂SO₄, and the effect of Sb₂O₃ was almost unrecognizable.
3) In the corrosion test with lead containing glasses, test pieces were corroded severely and contamination or devitrification of glasses and separation of metallic lead from glasses were observed.
4) In the corrosion test with other kinds of glasses, contamination of glasses occured only around test pieces. Effects of major components except PbO were considerably small.
5) Corrosion products on the surface of test pieces were MoO₃, MoO₂+MoO₃, Mo+MoO₂ or in case of SO₃^-- containing glasses (reducing condition), MoS₂. The authors are of opinion that the corrosion of molybdenum is presumably accelerated by formation and evaporation of MoO₃.

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It is considered that the emissivity, one of thermal properties, is an important charcteristic to be measured as well as electrical and mechanical properties in exploring and developing MoSi₂ as a heating element.
We measured the spectral emissivity of MoSi₂ in the temperature range between 800°C and 1700°C for the wave length of 0.65μ.
The method of the measurement is as follows.
A cylinderical sample of MoSi₂ is placed horizontally in a vacuum vessel and heated radially by a Mo heating element that is placed at the center of the sample.
The temperature of the sample is measured at the bottom of several pores of different depths, previously drilled on the wall of the cylindrical sample.
Since the thermal conductivity is approximately constant throughout the sample, the true temperature at the outer surface of the sample, T, can easily be obtained from measurements of T_a and T_b, the temperature at the distance γ_a and γ_b from the center of the cylinder respectively, by extrapolation.
Using the true temperature T and the apparant temperature T_B, the emissivity, E_λ, can be calcurated by the equation; log E_λ=9.62×10(1/T-1/T_B).
The result obtained is as follows. The emissivity is 0.83 at 800°C, takes the minimum value of 0.75 at 1150°C and increases herefrom with temperature to reach 0.87 at 1700°C.

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The crystal structure of tellurite (TeO₂) is similar to that of titanium dioxide which has high dielectric constant. TeO₂-containing glasses which have antisymmetrical (TeO₆) octahedra, as in the case of tellurite, show peculiar dielectric properties, namely, high dielectric constants and low dielectric losses. According to an experiment by Stanworth, however, thermal expansion of these glasses is very large, softening temperature or mechanical strength are low, and chemical durability is poor. In this paper, results are reported on experiments to improve electrical and mechanical properties by finding new glass forming regions in the system TeO₂-Ba(PO₃)₂-RPO₃(R=Li, Na, K). Rather stable glasses were obtained. Physical properties and chemical durability were considerably satisfactory except for glasses of high potassium content. At a room temperature dielectric constant and dielectric loss for 1Mc/sec is 15-26 and 0.002-0.008 respectively. Thermal expansion coefficients are 120-166×10^-7/°C (from room temperature to 200°C) and softening temperatures are 380°C-430°C. Relations between dielectric properties and glass structure are discussed.

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