The author has recently discovered numerous examples of natural high-tem-perature plagioclases more sodic than An 35 from some Miocene rhyolite lavas in Japan. The optical properties of these high-temperature sodic plagioclases differ distinctly from those of what are regarded as low-temperature plagioclases and are similar to those of synthetic high-temperature albite reported by O. F. Tuttle and N. L. Bowen. In this paper, the author presents new data on the refractive indices, axial angles, extinction angles, and Köhler-angles of these high-temperature plagioclases, and revised stereograms showing migration of optical indicatrices and twinning-axes in them.

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Alluvial soils of the Chikugo River contain predominant montmorin in the clay fraction, being different with general alluvial soils in Kyushu. It is safely concluded that at least a part of that monmorin has been derived from the weathering products of the so-called Tsukushi lavas, especially agglomerate in the upper stream of the Chikugo River. The montmorin is poor in magnesium and iron, rich in aluminium, and high in exchange capacity of cation, retention of ethylene glycol, and fixation capacity of ammonium ions. It seems to belong to aluminian montmorillonite such as beidellite.

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Electrical resistivity of pyrite has been measured over the wide temperature range from about -180°C to +400°C on some specimens from Japan. The data obtained show that the electrical conduction of natural pyrite possesses the properties of typical extrinsic semiconductor. The presence of some impurity energy levels causes rather low and various resistivities at rcom temperature, while the perfect crystal without such impurity energy levels should have the higher specific resistivity, about 10⁴Ωcm.. Some features of the impurity energy levels which are responsible for the extrinsic semiconduction are also discussed, but the origin of such levels is still unknown.

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The formulae for the number of counts per minute of beta-rays ejected from homogeneous rocks or ores and detected by an end-window Geiger-Mueller counter at a distance more than four centimetres have been calculated with the results as follows:
T=60πpNW/C^*G,
where
G=e^{-μ*_AH/[cosδ]}g,
g=(tan^-1H²+x₁²/XH-tan^-1H/X)XH/4,
or
g=(1/H²-1/H²+X₁²)S₀H⁴,
and μ^*_A: the absorption coefficient for air regarding the number of betarays (cm^-1),
[cos δ]: the mean velue of cos δ,
S₀: the effective solid angle at the point in which the extension of the central line of Geiger-Mueller tube meets the surface of the object,
other notations being the same as in the previous report.

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The permittivity of apophyllite, εC, measured at room temperature was 6.4. This value is not so large as is usually expected for a hydrated crystal and, therefore, the atomic polarization effect of the hydrogen atom perpendicular to the O-H…O axis of the hydrogen bond is smaller than in crystals containing the hydrogen bond of the O-H…O type. It is to be concluded that the water molecules in apophyllite are not tightly bound to the neighbouring oxygen atoms and are classified as normal water of crystallization. The temperature dependences of the dielectric constant were also studied.
The permittivity of analcite measured at 3 Mc. at room temperature was 6.5. A distinct dielectric dispersion was observed at room temperature in the audio-frequency region. From the observed data of ε′ and tan δ, the energies and entropy of activation were obtained: ΔF^*=12.7kcal/mole. ΔH^*=14.5kcal/mole and ΔS^*=4.8cal/deg. mole. It may be concluded that the water molecules in analcite are linked to the neighbouring oxygen atoms through the hydrogen bonds of energy of about 7.3kcal/bond and are distributed over a set of equivalent positions in the structure. The dielectric dispersion observed in the temperature region between 200° and 500°C. seems to be attributable to the polarizing effect of dipole cluster formation similar to that found in K₂HgCl₄•H₂O.

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