The present methods of proportioning ceramic raw materials are classified and the errors unavoidable in dry methods are discussed from a scientific standpoint.

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Continuing the previous study (This Journal, 1934, 42, 399), one of the present author S. Nagai carried on, in collaboration with Yoshio Kato, the studies on the relation between chemical compositions and water solubility or resistibility of window glass, chemical laboratory glass, industrial glass, etc. The main points of the present communication are briefly abstracted from the original Japanese paper, as following:
(1) Standard compositions of common soda-lime glass, i.e., SiO₂:72%, CaO:13% and Na₂O:15%, were changed in the amount of CaO, replacing by BaO, MgO or ZnO and fixing the amounts of SiO₂ and Na₂O nearly constant, as shown in the following table 1.
(2) These desired glass samples were prepared, by mixing the chemicals CaCO₃, Na₂CO₃, BaO, MgO, ZnO and pure silica sand, and melting the batches in chamotte crusible at 1400-1450°C of gas furnace. These glass samples were analysed and the following results were obtained, which were unfortunately a little deviated from the desired compositions shown in the table 1. The specific gravity of the. glass powder was also compared, and it was seen that BaO and ZnO increased the values of specific gravities and on the contrary MgO reduced the specific gravities.
(3) Various chemical glasses of beaker and flask and industrial glasses for the use of pressure gauge, were bought from the market, analysed and obtained the following results.
Among of these glasses high grade water resistibility can be obtained by increasing the amounts of SiO₂, B₂O₃, Al₂O₃, ZnO, Sb₂O₃ etc. and decreasing the amounts of CaO, K₂O, Na₂O, etc., from the following results of tests on water solubilities of these glass samples.
(4) These glass samples were crushed and sieved to grains, i.e., passing through 64 meshes/cm²-siev eand remaining on 144 meshes/cm²-sieve. These grains were throughly washed by absolute alcohol and completely dried in desiccator. The solubility of glass in water was tested in two ways.
I: The first method is to treat 5g of the above prepared glass grains and 200cc of distilled water in silver beaker for 2 hours on water bath.
II: The second is the autoclave method, i.e., 5g of glass grains was taken in silver crursible with 40cc distilled water and heated 2 hours in an autoclave under pressures of live steam of (1) 5 atm. and ca. 152°C, (2) 10 atm. and ca. 181°C, (3), 15 atm. and ca. 200°C, (4) 20 atm. and ca. 212°C, etc. After these heat tratments of both methods, the water was decanted and then titrated by 1/50-N-H₂SO₄ solution. The amount of titration in cc was a degree of solubility of glass alkalines. These both methods were already adopted in the first report and fully discussed (W. L. Baillie and F. E. Wilson: Journ. Soc. Chem. Ind., 1921, 40, 448 R; W. E. S. Turner: Journ. Soc Glass Tech., 1922, 6, 38, etc.). The results were fully compared in the following table 4.
From these results some important points were observed, i.e., (1) The alkaline earth component RO has the order ZnO>CaO>MgO>BaO of water resistibility of glass, (2) Among them ZnO is the most effective component to chemical and industrial glasses as seen by comparing the chemical analyses in the table 3 and the solubility tests in the above table 4 of glass samples of Flask II, Gauge Pipe I, II and III, and Gauge Prism, (3) These better glasses contain large amounts of B₂O₃ (6-8%), ZnO (4-6%) and Al₂O₃ (3-8%), and very small amount of CaO (1-3%), (4) Some glasses contain about 3.5% of Sb₂O₃, (5) Common window glass of soda lime glass type has smaller water resistibility than these chemical and industrial glasses, so that it must contain some other components

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A definite quantity of quick lime which had been prepared by calcining chemically pure calcium carbonate at temperatures varying from 900° to 1600°C every 100°C for 2 hours was put in a Dewar's tube containing a definite amount of distilled water of a definite temperature to compare the maximum rise of temperature and the time required for reaching the maximum temperature. The structure of the quick lime and the process of hydration of the quick lime when mixed with 1 to 6 times of water were observed under a microscope. Also X-ray analysis was made on the quick lime.
The maximum rise of the temperature and the time to the maximum temperature were almost alike for all products although the quick lime obtained at 900°C required a little longer time in reaching the maximum temperature since it had contained some carbonate. Inconsistency of the results with those of other persons such as K. W. Ray and F. C. Mathers (Ind. Eng. Chem., 1928, 20, 415) can probably be accounted for the fact that they had used natural limestone containing some alumina, ferric oxide, silica and other impurities.
The microscopic observation proved no marked difference in the structure of the products whereas the X-ray diffraction patterns were exactly alike for all quick lime produced at temperatures between 1000° and 1600°C.

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