Generally, on the repeating of lithia-silica glass, it starts to crystallize at the temperatures near or below the softening point to convert into the polycrystalline material without deformation (M. A. Matveev, V. V. Velya. Steklo i Keramika, 16 [10] 14 (1959)).
In the present study, various oxides were added as the third component to a lithia-silica glass of the composition, Li₂O 25, SiO₂ 75mol%, and their effects on the crystallization of the base glass on repeating were investigated.
It was found that there is a limit in the amount for each oxide, and the addition over the limit inhibits the crystallization of the glass giving rise to the deformation or surface crazing of the sample during repeating (Fig. 2 and Fig. 3). The limit of the amount of addition in mol%, for each of the oxides varied with the own property of the oxides as follows:
(1) For each of the series of alkali- and alkaliearth-oxide, which acts as the glass network modifier in the glass structure, the limit decreases with the increase of the size of cation, i.e.,
The value of limit: NaO_0.5>KO_0.5>RbO_0.5, MgO>CaO>SrO>BaO.
For the oxides with the cation of about the same size but of the different valency, the oxide with the cation of the higher valency has always the higher limit, i.e.,
The value of limit: CaO>NaO_0.5, SrO>KO_0.5, BaO>RbO_0.5
(Fig. 6 and Table 8).
(2) For the glass network formers (BO_1.5, AlO_1.5, PO_2.5 and AsO_2.5) and also for the imtermediates (BeO, PbO, CdO, ZrO₂, CeO₂, LaO_1.5) the limit was generally low compared with that for the glass network modifiers, with the exception for the oxides of transition element (TiO₂, MnO_1.5, VO_2.5, CrO_1.5, FeO_1.5, CoO, NiO) (Fig. 7 and Table 8).
The structural explanations were made of the above results in terms of the polarizing power, and the ability of strengthening the glass network, of the cation in the oxides introduced.

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The studies of the thermal properties obtained by load and spalling tests of the electro-molten masses appeared in previous papers, J. Ceram. Assoc., Japan, 68 [10] 237, J. Ceram. Assoc., Japan, 68 [12] 294 (1960), were carried out. The matrix was separated by heavy solution, and was subjected to chemical analysis. Based on the summary of the results obtained the author disscussed the relation between the structure and the thermal properties of the electro-molten masses composed mainly of dunite.
The results of load test, thermal expansivity, thermal conductivity as well as spalling have shown a considerable increase with the increasing ratio MgO/SiO₂ of MgO containing masses. With the addition of calcic materials the properties of the mass were put under the control of the ratios MgO/SiO₂ and CaO/SiO₂, and up to 7.5% CaO was effective for improving the results of load and spalling tests, while more lime than this limit lowered the load bearing temperature.
The effect of high aluminous materials were different in both sides of the line connecting MgO⋅SiO₂ and 2MgO⋅SiO₂ in the ternary system, MgO-SiO₂-Al₂O₃. In the domain rich in Al₂O₃ gave the refractories of higher load bearing temperature than in the other one. In general, the addition of alumina lowered the thermal expansion and improved the thermal conductivity and spalling. A trend was found that SiO₂, Al₂O₃, Fe₂O₃, CaO, and ZrO₂ intermixed in the matrix of the mass as solution or as microcrystals.

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It is known that the addition of SnO, Sb₂O₃, Fe₂O₃ and CeO₂ etc., the oxides of multivalent elements, promote the development, and stabilization of the colloidal colours obtained by reheating the glasses containing Au, Ag, and Cu. In order to know the mechanism of the function of so called thermoreducing agents, or sesitizers, in developing colours a series of experiments has been carried out taking Ag-glass as an example.
The composition of base glass was Na₂O 18.0, CaO 8.5, Al₂O₃ 1.5, and SiO₂ 72.0% by weight, and to which 0.025 gram atom of Ag₂O, and 1 or 4 gram atoms of 11 thermoreducing agents, i.e., TiO₂, V₂O₅, Cr₂O₃, MnO₂, FeC₂O₄⋅2H₂O, CoO, NiO, SnO, Sb₂O₃, Ce₂ (C₂O₄)₃, UO₂(NO₃)₂ were added.
The 20 glass samples prepared from the different combinations of sensitizers given above were subjected to the combinations of following heat treatments:
1) Holding for 10 minutes at 650°C followed, respectively, by cooling to 400°C in 2 hours at constant rate and then quenching to ordinary temperature.
2) Irradiation by ultraviolet rays.
3) Preheating at 800°C for 10 minutes.
The spectral transmission between 250 and 750mμ of the specimens which have developed colours by applying the combined treatments of above three types were measured, and the results were compared with the transmission of those containing no sensitizer and have passed through the exactly the same pretreatments.
Within the scope of the present experiments it has been shown that the ions of Cr, Co, Sn act effectively in the colour development by heat treatment, while those of Cr, Fe, Sn, Sb, Ce are effective in developing by ultraviolet irradiation.
Considering that these effects may be ascribed to the increase of the concentration of atomic silver, Ag°, during the heat treament, where the constants of the equilibria, such as
Ag°→←Ag⁺
M⁺→←M²⁺,
in which M is a multivalent element, are highly temperature dependent, the author was able to explain satisfactory the function of the thermoreducing agents, or sensitizers, by the difference of the temperature dependency of the equilibria.

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H. Poritzky has derived the equations which enable us to caluculate the stresses in glass with a sealed metal wire of circular cross section, and Arakawa has presented new formula representing the stresses in a glass cylinder sealing two diffrent metals and has proved that the formula are practically useful.
Extending these previous works the author has presented the equations, (4) in the text, which can be used for computing the internal stresses in a glass seal between two metal tubes under the same assumptions as those in Poritzky's paper.
In order to compare the experimental values with those calculated by the equation (4) photoelastic study has been carried out using two kinds of glass whose expansion coefficients are given as G-1 and G-2 in the text.
The principal stress difference of the two samples were measured by photoelastic method and the internal stresses were calculated in terms of the difference of the expansions of the glass and metal from annealing point to room temperature.
From the results it has been proved that the experimental results and those calculated by eq. (4) showed the satisfactory agreement in the radial and tangential stress.
The agreement between the theory and the experimental results of the axial stress was not so good, probably due to the end effect. However, the eq. (4) is may be regarded as being useful for the determination of sealing glasses and metals.

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Barium titanate ceramics were prepared in laboratory in order to know how the remanent polarization and dielectric properties of BaTiO₃ ceramic elements were effected by firing temperature and BaO, TiO₂ mole ratio used making BaTiO₃.
Test pieces were prepared from the lots in which BaO, TiO₂ mol ratio were changed from 0.990:1.000 to 1.020:1.000, and fired to the temperature ranging from 1350°C to 1460°C.
The results obtained may be summarized as follows. (1) In general, bodies deficient TiO₂ gave the test disks with increasing abnormal polarization phenomenon and dielectric loss (2) BaTiO₃ ceramics of 1 mole % excess TiO₂ did not show the abnormal polarization pheomenon, but the test pieces of decreasing more or less the total remanent polarization. (3) It was found that the abnormal polarization phenomenon resulted from the remains of hexagonal BaTiO₃ or Ba₂TiO₄, BaTi₄O₉, etc.

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