For the guidance of the study on the celite part, I have studied in order to reexamine the studies of both home and abroad on the brownmillerite.
For this purpose, by microscopic and X ray methods I have investigated on the each fired sample of the mixtures, whose mloar compositions are 3CaO:Al₂O₃:Fe₂O₃, 4CaO: Al₂O₃:Fe₂O₃, 5CaO:Al₂O₃:Fe₂O₃, 6CaO:Al₂O₃:2Fe₂O₃ and 6CaO:2Al₂O₃:Fe₂O₃, which had been studied by many investigators in the study of the celite part.
The results of my study on them are as follows:
(1) Each fired sample consists of 1-3 different crystals, and the principal mineral which occupies whole or most part of each sample is a ferric oxide series compound (perhaps, a solid solution), that has deep red and brown colour, fibrous structure, strong double refraction and high refractive index.
(2) In the crystal consisting of the ferric oxide series compound, that is the principal mineral of each sample, the zonal structure is found by the microscopic observation. This is a crystalline phase known in a solid solution.
(3) By the X ray analysis, each X ray powder photograph of these samples gives a diffraction pattern of 2CaO⋅Fe₂O₃ type, and the principal minerals seem to have the internal structure of strictly the same type, but each is only different in the interplanar spacing of lattice. Such a phenomenon is seen in a solid solution.
(4) From my experimentation, in the fired sample of 4CaO:Al₂O₃:Fe₂O₃, its lattice spacing is the same with the spacing of so-called brownmillerite that has been already reported by many investigators.
(5) The lattice spacing of each sample is reduced in the order of 2CaO⋅Fe₂O₃, 6CaO:Al₂O₃:2Fe₂O₃, 3CaO:Al₂O₃:Fe₂O₃, 5CaO:Al₂O₃:Fe₂O₃, 4CaO:Al₂O₃:Fe₂O₃, and 6CaO:2Al₂O₃:Fe₂O₃.
Thus, each principal mineral existing in each of the above five fired samples seem to lie in a solid solution series.
In my experimentation, it is considered that the principal mineral existing in the fired sample of 6CaO:2Al₂O₃:Fe₂O₃ is a solid solution that has the greatest miscibility.
But if we think of the existence of a compound in this series insistently, from the above result of the X ray analysis it is only right and proper to rather think of the existence of such a ferric oxide series compound of high lime-alumina as existing in the fired sample of the mix, 6CaO:2Al₂O₃:Fe₂O₃, than of the brownmillerite.
Thereupon, the brownmillerite (4CaO⋅Al₂O₃⋅Fe₂O₃) should be considered to occupy a region in a solid solution series between 2CaO⋅Fe₂O₃ and a compound of higher lime-alumina than 4CaO⋅Al₂O₃⋅Fe₂O₃.
Thus, the existence of the brownmillerite is still open to doubts.
(6) In the principal mineral of the ferric oxide series that exist in all fired samples of higher lime mixtures (5CaO: Al₂O₃:Fe₂O₃, 6CaO:Al₂O₃:Fe₂O₃, and so on) than 4CaO:Al₂O₃:Fe₂O₃, the more the content of lime in the mixtures increases, the more the content of lime-alumina in the principal mineral existing in its fired sample decreases.
(7) In 5CaO:Al₂O₃:Fe₂O₃, if investigated

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This article contains the results of the experiments, first, on the P. C. E. of the raw mixtures of the refractory cements, with or without addition of various oxides or frits, second, on the thermal linear change of the hydrated cements, third, on the softening behavior of herdened test pieces made of the mixture 3CaO:5Al₂O₃ fired at 1300°C. of the mixture added with 2% of ferric oxide and fired at 1300°C, and of a portland cement, an addition of 3 times of standard quartz sand being made to each cement or not, fourth, on the effect of silica added to the mixture upon the properties of the cements, and also, fifth, on the preparation of the cements from natural raw materials.
(1) The P. C. E. of the mixtures CaO:3Al₂O₃ and 3CaO:5Al₂O₃ were cone 37+ and cone 36+ respectively. An addition of 1 to 4% of Fe₂O₃, MnO₂, or frits to their raw mixtures or to the cements lowered the refractoriness by a few or several cones, Fe₂O₃ being most injurious. Silica was found to be harmful.
(2) The hydrated cements contracted rapidly at about 300C on account of dehydration.
(3) The cements proved to be more refractory under a load than the portland cement.
(4) Silica contained in the raw materials reduced markedly the hydraulicity of the cements.
(5) For the preparation of the refractory cement from natural raw materials, limestone and diaspore or limestone and Chojo-fireclay were compounded, the proportion of limestone being increased in order not to reduce the hydraulicity of the cements by the silica contained in the aluminous materials. The fired products together with a suitable grog gave excellent refractory mortars.

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A method is described for the determination of the carbon content of glasses. The effect of carbon content on the colour of the glass produced was investigated with reference to a parent glass SiO₂ 72%, CaO12, Na₂O 16 (when the carbon was added to the batch in the form of graphite, carbon black and cane sugar, both without and in the presence of sodium nitrate)

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The effect of composition on the thermal endurance of mixed alkaliboric oxide silica glasses is investigated. The testing procedure is descrived, using annealed rods 5mm. diameter and 30mm. long, having fire polished ends. The relation between thermal endurance and chemical composition is of approximately parabolic form, and is illustrated by a solid model.

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