Physico-chemical studies on the nature of adsorbed cations held on kaolinite surface, i.e. the change of the mean free bonding energy of adsorbed H⁺, and of the exchangeabilities of Li⁺, Na⁺, K⁺, Cs⁺ caused by drying the kaolinite below 600°C, were carried out.
It was concluded that kaolinites, regardless of their morphological properties, have power to fix almost nonexchangeably a considerable amount of above cations. The ability of fixing the cations increases with the increasing degree of drying, until kaolinite decomposes with the loss of lattice water, when the decrease of fixing power is observed. The fixing power varies a great deal with the radii of cations as well as with the degree of losing the water of hydration at a definite temperature, the samller cation and the larger degree of dehydration causing the more powerful fixation.
Drying brings with the decrease of ζ-potential of the clay surface suspended in water, and therefore the rehydration of adsorbed ions may not be reversible at normal temperature.
A new theory of the fixation of adsorbed cations, being quite different from any current theories which have been introduced so far by soil scientists, is advanced by authors. As the fixation causes the change of ionic distribution in electrical diffuse double layer, it would be natural to consider that the fixation may affect the properties of kaolinite-water systems. The influences of drying on the sedimentation of clay-water suspension were investigated. It was noted that the kaolinite dried even at such a low temperature as below 50°C showed a remarkable differences in sedimentation volume and settling rate from those of non-dried, original suspension. The authors are going to point out that the fixation phenomenon, first unveiled by them, would be very significant for the colloid chemical or rheological study of clay minerals and for the proper control in clay industries.

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As a tentative method of comparing the soundness of rock wool at elevated temperatures the sample was packed in a cylindrical vessel and heated gradually in an electric furnace (Fig. 1) to meaurse the temperature from which a sharp shrinkage begins to occur with or without compressive load (Figs. 2-6).
Heat resistivity is a property of qualitative nature being not able to be expressed by a numerical value, the authors, however, proposed to define it by the temperature at which the rate of shrinkage expressed by per cent per degree reaches to 0.1.
The temperature defined as above varies with the load applied during the measurement, with fiber diameter as well as with the bulk density of wool. But the change at this temperature agrees fairly well with the results of other observations such as the microscopic examination, and moreover, the total shrinkage up to this temperature is nearly the same regardless of the samples (Table 2).
Various kinds of rock wool were produced from the mixture. of oxides by melting the batch in an electric furnace, and attenuating the molten stream by jet.
In the system TiO₂-SiO₂-CaO there is a domain (hatched area in Fig. 13) in which good fiber is obtainable with a large yield. The heat resistivities of the fibers, however, are not excellent as shown in Fig. 7.
In the system Al₂O₃-SiO₂-CaO highly heat resistant wool may be obtained as shown in Fig. 8 and 9, when the CaO content is less than 10%, and the ratio by weight of Al₂O₃ and SiO₂ remains nearly 1 (Table 1).

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The effects of particle size distribution on the rheological, and other physical properties of wet ball-milled Amakusa pottery-stone, as well as the properties of the fired specimens prepared frmo the body each containing the particles of limitted size were studied. The mineralogical constitution, in particular, of the samples containing the particles of 7 microns and downwards obtained by elutriating of the milled products was also investigated.
The milling was carried out under different conditions to give the particles whose specific surface area covers from 10740 to 15170cm²/g. The green bodies classified according to 7 different grain sizes were fired at 8 different temperatures to measure their physical properties. The results obtained are summarized as follows:
(1) By wet ball milling with rather large quantity of water the amount of particles larger than 10μ decreases with time along a logarithmic curve, while the amount of medium size particles (5μ-10μ) increases at first linearly and then slows down with the elaps of time. The rate of gain in amount of the particles finer than 2μ is rather slow.
(2) The concentrated slips prepared by this way show not only thixotropy but also dilatancy at the same time owing to their grain size distribution.
(3) The finer the grains the less is the thermal expansion of green body, while the firing shrinkage increases with increasing fineness.
(4) While the firing temperature is still low a larger shrinkage was observed with the specimens having larger surface area, but after reaching the maturing temperature the firing shrinkage completes during the schedule as long as the surface area exceeds a certain value. This means that the smaller grain size reduces the maturing temperature and broden the firing range.
(5) During the low firing range the porosity and absorption of fired specimens are influenced by the packing of particles, but in maturing temperatures such properties are mainly governed by specific surface area. The relation between the firing temperature and the bulk density, ultimate strength of the specimens is just reverse what it has with the porosity.
(6) The reflection and gloss of the fired specimens are also influenced by grain size. In low firing range these properties are affected by the surface area, while in maturing temperature they are mainly influenced by the degree of packing.
(7) The above justifies that for use of Amakusa pottery-stone in a porcelain body such grain size distribution as 43-46% under 5 microns, 34-37% 5-10 microns, 22-11% on 10 microns, whose surface area lies between 12000 and 13000cm²/g, may be regarded as a standard.

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Experiments on the Flow patterns of gases in the melting chamber of an end-port tank were carried out by means of the two dimensional model with water and also the three dimensional model with gases of medium temperature.
The cold model experiments have thrown some new light upon the relation between the flow pattern of fluid and the working characteristic of this type of furnace, namely;
(1) the location of ports exerts considerable influences on the flow of gases, so that the so-called U-turn flow is not always stable in the case of gaseous fuel to say the least of it.
(2) the nearer are the ports locate to the side wall of the furnace the more stable will be the U-turn flow.
(3) the U-turn flow will be more or less stabilized with a new type of bridge wall projecting triangularly toward the direction of the flow of glass.
(4) in spite of the author's hope the even distribution of the flowing gases was found to be insufficient.
(5) there would be many chances for the stronger erosion of the furnace refractories as compared with the side port furnaces.
The lack of thermal similitude in two dimensional model was then made up by the three dimensional gas model in which the temperature at many points were measured to search for the pattern of flowing gases. The results obtained may be summarized as follows;
(1) owing to the effect of buoyancy the burner inclining less than 15° towards glass level does not give the flame which hits the glass surface.
(2) the deeper the burner is inserted into the melting chamber the longer and milder flame will be obtained.
(3) excepting the flame having comparatively larger momentum the so-called complete U-turn flame can scarecely be obtained.
(4) larger stagnant areas are formed in the center as well as near the various corners of the melting chamber.
(5) it was also observed that the U-turn flow was not always stable. The flow pattern will more or less be influenced by the furnace design, the operating pressure, the method of burning fuel, and especially the kind of the fuel.
(6) with the exception of buoyancy effects nearly all the phenomena observed in the hot model could will be interpreted from the results obtained in the cold model experiments, and the authors are coming round to the idea that a cold model is a very powerful means for studying the flow characteristics as well as the performance of a furnace.

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