The improving experiments were made on some coarse earthenwares and stonewares. Good cream and ivory colored bodies, white and brown colored engoves, new methods of slip decoration and no crazing magnesia glaze to clayey hody are descrived.

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The authors reported, in continuing the previuos studies on mixed Portland cements, the results of further comparative tests on high silica mixed Portland cements. The following summaries were abstracted from the original Japanese paper.
(1) Three sorts of natural siliceous earth, which are called “Keisan-hakudo, Yokei-hakudo and Kayo-hakudo”, and these are kinds of siliceous sinter obtained plentifully in volcanic districts. The following table 1 is the results of the total analysis and the table 2 shows the results of insoluble and soluble parts treated by 10%-NaOH and 5%-HCl solutions.
Table 1. Results of Total Analyses of Samples of Siliceous Earth
Table 2. Results of Soluble Analyses of Samples of Siliceous Earth
(2) Two sorts of Portland cement clinker were used to mix with these siliceous earths and ground to high silica mixed Portland cements. The mixing proportions and physical properties of the prepared cement samples were compared in the following table 3.
Table 3. Mixing Proportions and Physical Properties of High Silica Mixed Portland Cements
High silica mixed Portland cements have considerably small values of specific gravities, owing to the small specific gravities of high siliceous admixtures.
(3) The chemical compositions of these cement samples were analysed and the results are shown in the following table 4.
Table 4. Chemical Compositions of High Silica Mixed Portland Cements
Mixed Portland cements contain considerably large amount of insoluble residue in hydrochloric acid. Total silicic adi dexceeds 45-50%, so that these cements will be called silica cement, high silica cement or high silica mixed Portland cement. Total lime is, on the contrary, very little and does not exceed 35-43%
(4) These samples were tested on their compressive and tensile strengths of 1:3-cement-sand mortars by the method described in the “Japanese Engineering Standard” for Portland cement (JES 28) or for blast furnace slag cement (JES 29). The results are tabulated in the following table 5.
Table 5. Results of Tests on Compressive and Tensile Strengths of 1:3-Cement-Sand Mortars
These test by the so-called “dry mortar” of the standard specification is very favourable for these high silica mixed Portland cements and gives considerably large strengths, especially the tensile strengths. These ordinary strengh tests are not suitable to discuss the mixed Portland cements. So that, the authors studied already on the plastic or wet mortar test, which is the modified method from the Haegermann's method (G. Haegermann: “Die Pruefung plastischer Moertel”, Protokoll der Tagung des Vereins deutscher Portland-Zement Fabrikanten, E. V., Sept. 1929, S. 35; “Die Zementpruefung bei Anwendung von Moertel mit hochem Zementzusatz”, Report of the New International Association for Testing Materials, Zuerich, 1931, p. 669) and the Roš's method (Prof. M. Roš: “Die zukuenftigen schweizerischen Norman fuer Bindemittel auf Grundlage von Untersuchungsergebnissen der E. M. P. A. (Eidg. Materialpruefungsanstalt) an der Eidg. Tech. Hochschule in Zuerich: Die Pruefung der Zemente mit plastischer Moertel”, Diskussionsbericht Nr. 1, Mai 1925, Nr. 10, April 1926, and Nr. 60, September 1931). The plastic mortar is from cement: fine sand (sea sand for sheet glass industry in Japan, which is obtained from Korea and has the fineness of 400M/cm²-3600M/cm²): Japanese standard sand in the proportion of 1:1:2 and 60-70% of water-cement ratio, which will be determined by the small flow table and the flow of 200%. The results are shown in the following table 6.
Table 6. Results of Tests on Compressive and Bending Strengths of Plastic Mortar
These results from the plastic mortar tests are more suitable to compare Portland cement,

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Clinker produced by the wet method is sieved with I″, 3/4″, 3/8″, no 4, 49mesh/_??_cm. The classified clinker is ground with 3% gipsum by a test ball mill. Auther made chemical analysis and strength test according to the japanese standard specification
Conclusion.
1) H. M. of clinker in middle size is greatest.
2) S. M. is greater when clinker is greater insize.
3) A. I. is the same in the case of S. M.
4) The strength is the better the higher of H. m. when S. M. is almost the same but when the S. M. is great different, it is not always true.
5) Tensile strength is more influenced by the S. M. than compressive strength.
6) When the H. M. is the same, cement is the better the higher S. M.
7) Clinker dust is always bad. It is a proof of the bad condition in the kiln.

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In vestigations at very high temperatures require the solution of a number of interesting problems. Some modern means of obtaining extremely high temperat ures in the laboratory are: Use of an electric arc in connection with two hollow mirrors; tungsten and molybdenum furnaces for work in oxidizing or reducing atmospheres or in the vacuum; and gas fired zirconium oxide furnaces. Electron bombardment of solids is the most satisfactory metho l for vacuum work. High temperature investigations under very pure conditions have been carried out recently using the radiant energy of the sun. These investigations may be carried out in any atmosphere or in the vacuum. Both electron bombardment and the sun furnace allow to obtain temperatures limited only by the evaporation of the sample. Some other means are mentioned for obtaining very high temperatures for very shcst intervals.

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