A series of experiments were carried out for investgating the factors having an effect on the color of chromium-containing glasses, expecting that the coloration would give a clue for elucidating the properties of the base glasses.
About 100 samples extending over silicate, borate and phosphate glasses containing chromium oxide, were melted in, respectively, oxidizing and reducing atmosphere. They were used for measuring spectroscopic transmission. Also the absorption at 280°-300°C of some specimens were measured in order to know the effect of temperature.
The change of the color of chromium-containing glasses may be attributed to two separate origins; one due to the equilibrium between Cr³⁺ and Cr⁶⁺, and the other due to the influence of electric field of 6O^2- coordinating Cr³⁺. The former may be explained by the atmosphare of glass melting and the basicity of base glass, and the latter in connection with the “single bond strength” of base glass, using the result obtained by the recent investigations of Bates and Douglas,
It is thus possible to give a semi-quantitative explanation of the blue color of the chromium-containing borate glass.
As far as the present experiments are concerned the change of the transmission curve by heating may be explained by the increase of Cr³⁺-O^2- distance. However, it is open to question whether this idea could be extended to the marked change of transmission at higher temperatures.

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種々のLi₂O-Al₂O₃-SiO₂系結晶原料, すなわちLi₂O・Al₂O₃・2SiO₂ (ベータ・ユークリプタイト), Li₂O・Al₂O₃・3SiO₂, Li₂O・Al₂O₃・4SiO₂ (ベータ・スポジュメン) およびLi₂O・Al₂O₃・8SiO₂ (ペタライト) の組成の結晶粉末を骨材とし, その各々にLi₂Oを含む種々の珪酸塩ガラスを, その含有率が5, 10, 20%となるように混合し, プレス成形した後に, それらの試料を種々の温度で加熱して, 先ず変形度を調べ, ついでこれら焼成試料の吸水率, 曲げ強度の測定, 急熱急冷試験, 組織の顕微鏡観察, X線分析などを行なった. その結果,
1. ペタライトを骨材とする場合は, リチア含有ガラスの添加により試料の焼成温度範囲は最大40℃となり, 焼成試料の曲げ強度は最大650kg/cm²となった (ペタライトのみの場合は約300kg/cm²). またリチア含有ガラスを10%含有させて焼成した試料 (形状寸法5×5×50mm) は1000℃から室温の水中に急冷を繰返しても強度の低下はなかった. 他のLi₂O-Al₂O₃-SiO₂系結晶原料を使用したものはガラス添加の効果は小さかった.
2. ペタライトに混合するのに適当なガラスの組成は, Li₂O含量4-20%, SiO₂含量50-90%であり, 混合量は5-20%が適当であることを認めた.
3. ペタライトとリチア含有ガラスとの混合試料の焼成過程, 磁器化範囲が広くなる理由, 機械的強度および耐熱衝撃抵抗性の向上の理由などについて考察を加えた.

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The fluorescent X-ray analysis was successfully applied to determine the six major components in portland cement.
The measurements were carried on to determine the contents of Fe₂O₃, CaO, SO₃, SiO₂, Al₂O₃ and MgO, by a X-ray spectrograph with specially designed sample chamber, using ammonium dihydrogen phosphate (d=5.324 a. u.) as an analysing crystal, and in an atomosphere of hydrogen by means of gas-flow proportional counter and pulse height analyser.
Calibration curves were prepared from the commercial cements containing various amounts of above oxides.
In order to avoid the error caused by un uniformity of packing powder samples were pressed to the plates of the size 2cm×3cm under the pressure of 300kg/cm².
The determination of the components were made by comparing the intensities of FeK_αI, CaK_αII, SK_αI, SiK_αI AlK_αI, and MgK_α I of unknown to those of standard samples which were polished piece of Basalt, Calcite, Sulpher, and the plate of metallic magnesium.
The correction of the absorption effect of incident fluorescent X-ray was made taking into account of the mass absorption coefficient as well ss the geometrical characteristics of the apparatus.
Standard deviation of the analytical values obtained by the method given above with the calibration curves were 0.06% for Fe₂O₃, 0.14% for CaO, 0.11% for SO₃, 0.27% for SiO₂, 0.27% for Al₂O₃, and 0.16% for MgO.
Differences of the moduli obtained by fluorescent X-ray and chemical analysis were 0.03, 0.10, 0.08, 0.03 in silica modulus (SM), activity index (Al), iron modulus (IM), and hydraulic modulus (HM), respectively.
It has been proved that the complete determination of six major components given above can be carried out within about an hour, and that the proposed method may be applied as a rapid analysis for the quality control in the portland cement industry.

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From the standpoint of the utilization of the pottery stone of poor quality, the removal of iron content of Izumiyama pottery stone by the hydraulic cyclone was investigated.
According to the mineralogical study of Izumiyama pottery stone by N. Yoshida, our department, it is determined that the main mineral containing iron is pyrites. The specific gravity of pyrites is higher than those of quartz, sericite, kaolin which are the main mineral compositions of this pottery stone.
Therefore, it is preferable to use the hydraulic cyclone in order to remove the pyrites content.
The three samples of Izumiyama pottery stone of poor quality are provided by crushing with the ball mill during 6, 9 and 12 hours respectively.
The numerous experiments were carried out in order to clear up the relation between the operating conditions of hydraulic cyclone and the removing ratio of iron content.
The experimental results obtained are summarized as follows.
(1) The best operating conditions are as follows; the pulp density, 10%, feed pressure, 1.0 kg/cm², diameter of underflow nozzle (Du), 9.0mm.
The best results were obtained in the case of the sample crushed with the ball mill during 6 hours.
(2) The removing ratio of iron content in the best operating condition is 48%. In this case, the iron content of the feed sample is 0.729%; therefore, the iron content of the overflow sample is 0.729×0.48=0.35% Fe₂O₃.
The actual quantity of overflow sample is 48% of the total quantity of feed.

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Influence of gamma-irradiation upon properties of glasses have scarcely been studies excepting phenomena such as coloration and fluorescence caused by the irradiation. In this study, therefore, not only the influence of gamma-irradiation upon the electric conductivity of glasses, but applicability of glasses exposed by gamma-rays to semi-conductive glass or radiationdosimeter was studied.
The electric conductivity for ten kinds of glasses were measured after irradiating gamma-rays up to the maximum dosage of 10⁷r. using Co⁶⁰.
For the measurement of the electric conductivity, a vacuum tube voltmeter was used for the range of low resistance values and a vibration reed electrometer for the range of high resistance.
The result of the measurement showed that no change in electric conductivity of the glasses occured by the irradiation of 10⁷r. and consequently the gamma-irradiation to the glasses was found to be unapplicable in making semi-conductive glass and glass-dosimeter.

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