Eight kinds of American refractory clays, occured in Missouri and Kentucky districts were studied in laboratory and in actual manufacturing course for the purpose of making blast furnace brick.
The results are summarizied as follows;
1) By chemical studies; Missouri flint clay is the purest (high alumina and low iron content) and Missouri semi-flint clay has nearly the same composition as Kentucky flint clay. The soft clays, both from Missouri and Kentucky, have more silica than the flint clay owing to the presence of impurities.
2) By mineralogical studies (X-ray analyses); -Missouri flint clay is pure Kaolinite, but Kentucky flint clay and Missouri semi-flint clay consist of mainly low grade kaolinite minerals with small amount of quartz. The soft clays consist of kaolinite minerals and considerable amount of quartz.
3) By physical studies (thermal expansion, thermo-balance, viscosity, and change porosity or density after firing); -these clays are classified in three groups, i.e. (i) Missouri flint clay, (ii) Kentucky flint and Missouri semi-flint clay, and (iii) soft clay.
4) Blast furnace bricks, both for bottom and stack linings, were also made from these clays in the industrial plant, and their characteristics were compared with that of other American and German Blast furnace bricks.

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1) 9種のガラス試料を使って高温静滴法 (セシルドロップ法) でそれらの表面張力を, 又真空, 窒素および空気中における黒鉛及び白金面上へのそれらの接触角をそれぞれ測定し, 付着仕事を計算した.
2) その結果, 液の表面張力と濡れ度とは必ずしも常に比例的関係にないことを示し, 黒鉛に対するPbOやFe₂O₃を含むガラスのように, 濡れの源動力はむしろ固・液界面張力の減少にあるということを例証した.
3) ガラスの成分と付着仕事について考察し, 黒鉛に対するガラスの濡れは, ある組成のガラスについては著しく大きいことを見出し, これはそのガラス中の成分が試験温度で還元されることによるのであろうと推察した.
4) 雰囲気による濡れの変化の速度については液滴の粘性のみならず, γ_lおよびAの変化についても総合的に考うべきであることを示した. そしてまた, ある条件では液の粘性がこの速度から比較し得ることを述べた.
この研究を実施するに際して, 人造黒鉛板は日本電興株式会社の川畑健雄氏が提供され, 実験装置およびその組立については, 三井金属鉱業株式会社および当研究室の田村四郎氏らが協力された. これらの諸氏に対して深く謝意を表する.
なお, 界面化学的見地から, 都立大学教授理学博士佐々木恒孝氏および東京工業大学小島研究室理学博士稲葉安養子氏の有益なる助言を賜ったのでここに厚くお礼申上げる次第である.

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The pottery stones, named “Tarumizu Toseki” are found in Osumi peninsula, Kagoshima Prefecture.
In this paper, the results of their chemical analyses, mechanical analyses, X-ray analyses, electron microscopic observation and other various thermal tests were discussed.
The results are as follows,
(1) Main components of Tarumizu pottery stone are orthoclase, albite, quartz (including some cristobalite, and chalcedony), sericite (including illite), and hydro-hall-oysite (including meta halloysite), while it is entirely devoid of kaolinite.
(2) The mixtures of clayportion and fine grains of this stone are suitable for vitreous porcelain bodies. The medium grains are possible to substitute the commercial feldspars in ceramic use, The coarse grains contain a little amount of coloured impurities.

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A sample of brick was taken from a zebra roof of a 40-tons open-hearth furnace after 402 heat services. The mineralogical constitution of five coloured layer zones in this brick was studied by the aid of microscope and integration stage. The chemical composition, specific gravity, and weight percentage of matrix in this brick were determined by the following two methods. 1) From the microscopic observation the volume percentages of quartz, cristobalite, tridymite and matrix were first determined in each zone, and then the chemical composition and specific gravity of each matrix were calculated from the results of chemical analysis and specific gravity of each zone. 2) The matrix in each zone was separatedfrom the SiO₂ modifications by heavy liquid method, and the chemical composition and the amount of matrix were determined directly. As compared with the former method, the latter method gave a higher value of silica of matrix because of imperfect separation.
The results obtained may be enumerated as follows;
1) As for the changes in composition with distance from the hot face, the high concentrations of Fe₂O₃, CaO, Al₂O₃ and MgO in zones II and III are caused by migration of the original matrix in the brick from the hotter face. On the other hand, the decrease of Al₂O₃, MgO and CaO contents in the working face (zone I) may be due to washing out by splash of the slag, and the increase of iron oxide content may be due to formation of magnetite by the decomposition of ferrous silicate under oxidizing conditions.
2) The content ratio of silica to total amount of other oxides in the matrix was 3.5:1 in the hot face and 2:1 in the middle area.
3) In the low temperature area this ratio was 4:1 by the imperfect separation of microcrystalline tridymite.
4) On the hotter area of the silica brick adjoined to a chrome-magnesite brick, iron oxide and magnesia migrated into the matrix of silica brick from chrome-magnesite brick.

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The relation between electrical conductivity and temperature or voltage of sodalime glasses which underwent various heat treatments was studied. It is known that the heat of activation ΔH* in Rasch-Hinrichsens' formula, log ρ=-A+ΔH*/T where ρ is the specific resistivity, A is a constant and T is the absolute temperature, increases gradually in the course of the stabilization of the glass. It was found by the authors that the constant A also increases in that interval and that it changes exactly linearly with ΔH*. Similar relationship between A and ΔH* can be seen in some chemical reaction rate processes, namely in Mayer's rule for oxide semiconductors or in the change of Richardson's formula for electron emission of metals with the pressure of adsorbed gases, etc. Therefore, the stabilization of glass is thought to be caused by the mechanism of the same type common to these processes.
Also it was found that the inclination of the linear part of the curve which represents logarithm of the resistivity of glass vs. voltage in the region of high field strength decreases slightly by annealing the glass. It shows that the width of the potential barrier for the alkali diffusion in glass decreases with the progress of the stabilization, and that the above mentioned change of A is caused by the increase of the entropy of activation ΔS*.
The free energy of activation ΔF* was calculated on several assumptions. It was indicated that when the glass is treated at a constant temperature, ΔF* changes little while ΔH* and ΔS* increase, and that when the glass is cooled by constant rate, the increase of ΔF* becomes a little larger. The level of ΔF* when the glass is treated at a constant temperature or cooled at a constant rate is not the same even for the parts of equal density.

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