Der Verfasser versucht der Brennverhalten von der feldspatigen Titan-Porzellan und den spezifischen elektrischen-Wiederstände bei den hohen Temperaturen, die Verlustwinkeln und die Dielektrizitätskonstanten bei Hochfrequenz masz.
In den Zusammenfassung, den Einflussen der chemischen Zusammensetzungen und Brennstemperaturen auf den verschiedenen Eigenschaften von der Porzellan-Masse aus betrachteten.

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The resistance of refractories to spalling is better compared by direct methods than by formulae based on theories, since the formers are more reliable than the latters. The present authors have proposed a new method of testing the resistance. Several magnesite bricks on market and experimental magnesite bricks have been tested by the method.
(1) Spalling test. Small test pieces are heated at about 1000°C to decompose basic carbonates. After cooling, modulus of elasticity at room temperature (E₁) is determined. Then they are suddenly put in a furnace 900°C hot, are heated at the temperature for 10min., are cooled on a fun for 6min., are left in room for 15min., and are dried. After repeating 4 more cycles of these proceedures, moduluo of elasticity at room temperature (E₂) is determined. Spalling tendency (S) is expressed by the formula, S=100(E₁-E₂)/E₁.
(2) The test is delicate and is free from errors due to the inequality of the test pieces, since each test piece is examined for both E₁ and E₂.
(3) Among magnesite bricks on market Radex is particularly excellent.
(4) If the proportion of the fine powder is kept constant, the effect of the difference in the fineness of the coarse grains on the resistance of the refractories to thermal shock is slight.

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Test pieces were formed of a coarse body and of a fine one, both prepared of a Manchurian magnesite clinker, and were then fired to temperatures varying from cone 12 to 28. Their physical properties such as fire-shrinkage, absorption, porosity, apparent sp. gr., and bulk sp. gr. have been examined. Then their spalling tendencies have been determined by the method described in Part X and also the numerical values of the ratio of modulus of rupture to modulus of elasticity have been computed.
(1) The spalling tendencies determined directly have been lowest for the firing temperatures of cones 14 to 16 and have risen abruptly with increasing vitrification at higher temperatures.
(2) The rise of the spalling tendencies due to vitification have been gradual for the coarse body and sudden for the fine body.
(3) Even magnesite refractories fired adequately may lose their spalling resistance in service by vitrification caused by the action of slag, flame, etc.
(4) On the contrary, the calculated resistance to thermal shock is increased with increasing firing temperatures.

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Various sample glasses have been made by substituting CaO by CoO in such proportion as 0.01, 0.05, 0.1, 0.5, 1, 2, 4, 6, 8, 10 and 12% in a base glass composed of 72% SiO₂, 12% CaO and 16% R′₂O where R′₂O being consisting of Na₂O, K₂O and Li₂O.
The glasses have been checked dy total analysis and found that they are approximately of expected composition.
Polishing them up in 1mm thickness and their transmission curves of wave lengths in the range of ultraviolet rays and visible light have been obtained; likewise by taking them polished in about 5mm thickness their transmission curves of infra-red region have been sought.
The degree of coloring in each sample glass has also been tested.

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