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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The processes which take place in the hydration of pure calcium silicates when they are gauged with 1, 3, 6 and 9 times of water have thoroughly been traced up to three months under a microscope. The samples of the silicates were prepared at following temperatures as reported in Part 1: 3CaO⋅SiO₂ 1700°C, and 1800°C, 2CaO⋅SiO₂ 1700°C, 3CaO⋅2SiO₂ 1450°C and 1475°C, and CaO⋅SiO₂ 1500°C.
(1) The hydration of 3CaO⋅SiO₂ and 2CaO⋅SiO₂ has occurred quicker than that hitherto reported by others. 3CaO⋅SiO₂ begn to hydrate in about 4 hours. produced crystals of Ca(OH)₂ in columns and hexagonal plates in 4 to 5 hours, and began to form silicic acid gel in droplets after 40 hours. 2CaO⋅SiO₂ hydrated after about 40 hours producing silicic acid gel; However no crystals of Ca(OH)₂ were found.
(2) No difference has been observed between the action of water and that of lime water used in gauging.
(3) Any decrease in the amount of water has encouraged the formation of crystal nuclei and increased number of the crystals as well as quantity of the gel.
(4) No change has been observable with the preparations of 3CaO⋅2SiO₂ and CaO.SiO₂ within three months.

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[in Japanese]

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