The authors, in the present report, studied on the effects ot alumina and magnesia on the solubility of soda-lime glasses in water. The brief summaries are abstracted from the original Japanese paper, as following:
(1) Standard compositions of soda-lime glass, i.e., SiO₂: 72%, CaO: 13% and Na₂O: 15%, were changed in the amounts of CaO and Na₂O, by fixing the amount of SiO₂ nearly constant, as in the following table 1.
Table 1. Standard Chemical Compositions of Glass
(2) These glasses ware prepared, by mixing chemicals, i.e., CaCO₃, Na₂CO₃, SiO₂, Al₂O₃ and MgO, and melting in chamotte crucibles at 1400-1450°C of gas furnace. The prepared glass samples were analysed and the following results in the table 2 were obtained, which were unfortunately a little deviated from the standard compositions shown in the above table 1.
Table 2. Chemical Compositions of Prepared Glasses
The tow samples were added as comparative samples, the one being the laboratory beaker glass and the another being the refreshing bottle glass. The beakes glass contains very large amount of soda, and is very soluble in water as shown in the following tables.
(3) These glass samples were crushed and sieved by the following three sieves, i.e., (1) 64meshes/cm² sieve, (2) 144 meshes/cm² sieve & (3) 225 meshes/cm² sieve. Two sorts of grains, i.e., (I) grains sieved between 64 meshes/cm² and 144 meshes/cm² sieves, and (II) grains between 144 meshes/cm² and 225 meshes/cm² sieves, were used in the present studies. These grains were completely washed by absolute alcohol and desiccated.
(4) Solubility of glass in water was tested in two ways. The first method is to treat 5g of grains and 200cc of distilled water in silver beaker for 2 hours on water bath. After the boiling the water was decanted and. titrated by 1/50-N-H₂SO₄ solution. The amount of titration in cc was a degree of solubility of glass, as shown in the following table 3.
Table 3. Comparison of Solubilities of Glasses in Water tested by Atmospheric Pressure Boiling
From these results, it is clearly observed that the glasses containing alumina are most difficultly soluble and the magnesia containing glasses are, on the contrary, most soluble in water.
(5) The second method is the autoclave method, which was already treated and discussed (Journ. Inst. Chem., 1920, 202; W. L. Baillie and F. E. Wilson: Journ. Soc. Chem. Ind., 1921, 40, 448R; W. E. S. Turner: Journ. Soc. Glass Tech., 1922 6, 38). The sample (I) grains was taken 5g in silver crucible with 40cc distilled water and heated 2 hours in an autoclave under pressures, (1) 5atm. and ca. 153°C, (2) 10atm. and ca 180°C, (3) 15atm. and ca. 200°C, (4) 20atm. and ca. 212°C, etc., and then the dissolved water was titrated by 1/50-N-H₂SO₄ solution as above described. The Results were shown in the following table 4.
Table 4. Comparison of Solubilities of Glasses in Water by Higher Pressure Heating in Autoclave
These results are quite equal to those in the above table 3. Alumina is very effective to make glass resistive to water and magnesia is nearly equal to lime or rather worse than lime.
The authors wish to continue the study further and report hereafter.

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1 第1報所載の純珪酸石灰即ち3CaO・SiO₂ (合成温度1700℃及1800℃), 2CaO・SiO₂ (同1700℃), 3CaO・2SiO₂ (1450°及1475℃) 及CaO・SiO₂ (1500℃) に1, 3, 6及9倍の水を加へたるプレパラートを作り, 3ヶ月に亙りて其水和過程を顯微鏡にて觀測せり。
2 3CaO・SiO₂及2CaO・SiO₂の水和は從來發表せられたるものよりも早く, 前者は4hr位にて水和し4-5hrにてCa(OH)₂の柱状及六角板状の結晶を生じ40hr以後に珪酸の滴状ゲルを發生せり。 2CaO・SiO₂は40hr頃より水和しゲルを生成したるも, Ca(OH)₂の結晶を認めざりき。
3 水の代りに石灰水を用ふるも著しき差異を認めざりき。
4 水量少き程結晶核の生成早く結晶の數及ゲルの量多きを認めたり。

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總ての利用し得る分析をプロットした第1圖, 第7圖の2つの三角圖表及び重要な比に對する度數曲線を作つて行つた粘土及びボーキサイト質鑛物の統計的研究は是等鑛物を, 純化學的の立場から分類した。 此研究の結果は鑛物であると呼ばれてゐた物質の中で, 一定の鑛物種に屬するものと認め得るものは極僅少に過ぎないで, 他の大部分は是等鑛物の混合物であるか, 若くは夫等の含水生成又は色々の成分の含水膠質である。 斯くして明確に結晶状の鑛物は次の樣に簡單なものになる。
パイロフイライト H₂O・Al₂O₃4SiO₂
カオリナイトと其の異性體 2H₂O・Al₂O₃2SiO₂
ダイアスポア H₂O・Al₂O₃
ギブサイト 3H₂O・Al₂O₃
是等の鑛物以外にテルメーライト, アノキサイト, アロファン等の樣な物質は明確な統計的證據はないが存在する可能性のある種類である。 ベントナイト質鑛物は純, 珪酸アルミナには屬さないで別の群に入れるものである。
三角圖表H₂O₃-Al₂O₃-SiO₂ (第2圖) 上の主要な點で表はされる物質の計算上の化學組成

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