In 1927, Prof. W. Jander experimented the reaction rate of solid particle and derived the following theoretical equation;
(1-3√1-w)²=kt,
where w was the fractions of reacted part in sold particle, t the time and k the constant.
The author pointed out that Jander's equation, based on the assumption of the equal particlesize, would not hold good of actual particle that had a irregularity of particle-radus.
Considering on the statistical distribution of particle-size, the author derived a new theoretical equation and criticized Jander's resalts of experiment on this point of view.
The equation is
1-w=∫(r-q)³f(r)dr/∫r³f(r)dr,
where r is the radius of particle, f(r) the distribution function of the radius and q the thickness of reacted layer in the solid particle.

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I have summarised the experimental data of Ramaneffect, Infra-red spectra, depolarisation degree in the crystal quartz. From the consideration of Raman-effect of organic silicon compound, I have calculated the force constant by these main Ramanlines, and applied these values of force constant to theoretical formulas, and explained many other Ramanlines of crystal quartz.
It has been shown that these calculated frequencies agree with the experimental values.
Then, I have concluded that there are the following vibration types in the crystal quartz, i.e. SiO₄ tetrahedron vibration, Si₂O₇ vibration, and SiO₃ chain vibration.

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With the object of determinating an industrial preparation method of pure zirconium oxide from zircon sands of Formosa, we tried to fuse the very finely pulverized powder of them with the fusing mixture, NaOH and Na₂O₂, and to lixiviate with hot water.
The remaining residues were treated with HCl and dissolved into chloride solution.
The solution was evaporated to dryness on heating to expel acid fune, and the dried mass wass held at about 100°C during several hours to dehydrated silica gel and then lixiviated with water to remove the silica. The silica-free solution of ZrCl₄ containing of FeCl₃ and TiCl₄ as impurities, wa neutralized with ammonium water to very weak acidity not to distinguish the precipitated hydroxides and boiled, bubbling SO₂ gas into it, when Zr-hydroxide falled by hydrolysis with Ti-hydroxide and Fe-chloride remained in the mother liquor.
The hydroxides were dissolved in the small amount of H₂SO₄ and the sulphate solution was evaporated to dryness and heated to 650°C in the electric furnace to expel the excess of H₂SO₄.
After lixiviating the cold mass with small water and filtering the insoluble matters, the sulphate solution was diluted to the ratio 1:50 of the cake and water.
On standing of the diluted solution during a week, the pure Zr-basic sulphate was crystalized out and calcinedd at 1000°C, when the ZrO₂ of 99% purity was prepared.

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In continuing the previous studies (Report I and II) on reclaiming of gypsum waste mould used in the pottery industry, the method was carried on by boiling powder of waste mould gypsum with dilute solution of alunnium sulphate, and was obtained well crystallized tablet crystal of gypsum CaSO₄.2H₂O. This reciaimed gypsum crystal was proved to be of superior quality to make calcined gypsum CaSO₄.1/2 H₂O, which has the setting time of moderate speed and large hardening tensile and compressive strengths.

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In the present paper, it was studied the conditions of making of moulding products from calcined gypsum and urea-formaldehyde resin. At first, the effect of drying temperature of moulded products, and nextly, the effect of hardening agent, especially 10-15% solution of Various ammonium salt of strong acid, i.e., NH₄Cl, NH₄NO₃, (NH₄)₂SO₄, etc. The water solution, in which urea dissolved in water, formaline and 5% ammonia water mixed in the volume ratio 3:5:0.3, warmed gradually about to 98°C. Thus, obtained transparent initial condensation product, in which resin part is about 42-44%, was mixed to calcind gypsum in various proportions and stirred few minutes. This condensation resin mass was moulded to small cylindrical mould and examined the effect of drying temperatures, 50, 60, 70, 80, and 90°C, by the compressive strength. Nextly, the effect of hardening agent, i. g., ammonium nitrate, sulphate, chloride and chlorate, which were added by 10-15% water solut ion. The effect of these hardening agens was tested by the hardness of the moulded piece. By these testings, the gypsum-artifitial resin moulding products was proved to have large compressive strength and hardness to be useful for making various small moulded products, as button, handel, etc. This studying is now being continued and the further results will be reported hereafter.

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For the borosilicate glasses in which the mol ratio of SiO₂ to B₂O₃ is larger than 3:2, the decrease of the fiber elongation rate with time under constant temperature and weight was found at the viscosity of about 1.5×10¹² poises provided that the glass did not contain much alumina. It was deduced to be due to the “xy₄-group” formation in these glasses on the grounds of several experimental facts. Also the “xy₄-group” formation in these glasses should be accompanied by the separation of the glass into two phases, one is rich in SiO₂ and the other in Na₂O and B₂O₃, i.e., one is high and the other is low in the temperature of melting. It is related to the phenomenon of the faint milkiness or opalescence which borosilicate glasses often assame during heating. By the considerations based on various experimental facts, it was concluded that when a small amount of the network modifying oxide of the cation with the valence three and upwards is added to the low alkali borosilicate glasses in which the mol ratio of SiO₂ to B₂O₃ is larger than 3:2, several “xy₄-groups” are gathered together by the cations of the modifying oxide causing a larger separation, and by the crystalization of silica in the SiO₂ rich phase in the form of ultra-microscopical crystals of cristobalite, the opalization takes place.
In the course of the above experiments on elongation and opalization, it was noted that the alumina content of the glass seems to greatly decrease the “xy₄-group” formation. It was deduced and also experimentally verified that by the formation of the “xy₄-groups” in the glass, the thermal expansion coefficient is reduced, and by the accompanying separation of the glass into the low melting and the high melting components, the transition temperature is lowered and the contraction temperature is raised. It is, therefore, very desirable to increase the number of “xy₄-groups” in glass with a view to improving its properties especially for glass-working. For this purpose, two methods may be available, namely, (1) by cooling the glass slowly through the “xy₄-group” formation temperature range, or (2) by decreasing the alumina content of the glass. By applying the latter method to the glass used for the production of the large type transmitting tubes, the failure of glass due to fracture in the process of sealing was reduced than heretofore as much as about 1/7. The decrease of the chemical durability accompanied by the decrease of the alumina content was satisfactorily compensated by the use of two kinds of alkali oxides instead of one.

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本年4月G. H. Q. 天然資源局の推薦により, 滯在日藪90日の豫定でアメリカへわたり, 筆者の專問域の研究現状を視察することが出來た。4月19日東京より船でSeattleへわたり, 5月1日Seattleに到着し, 合衆國内の旅行はすべて汽車を利用し, 8月9日San Franciscoを船で出發し8月23日歸國した。旅行プランの大綱及び各地の案内その他一切の世話はアメリカの鑛山局の盡力によりなされ, 多忙ではあつたが能率的の旅行をすることが出來た。宿泊地はSeattle以下19ケ所で, 視察したところは各大學の (地質, 鑛物, 鑛山, 化學及び窯業の各) 教室, 約22ケ所, 民間及び官廰所屬の研究所約16ケ所, 野外巡檢約5ケ所, 窯業會社約2ケ所で, 總計約200人の人々と意見を交す機會を得た。この中で特に權威といわれる人達と特に充分意見を交えたが, 筆者の專問に關しての事柄については, お互に打てばひゞくというような理解に達したことは忘れることのできない滿足であつた。目的は地質鑛物學の最近の研究技術の視察にあり, 特に粘土鑛物學のそれに重點を置いた。ここでは, その中より粘土鑛物の研究技術の現状に就て報告する。

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