The first experiments with zone-plates for the air-wave of wave-length 2 cm are deseribed

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The mean inner potential of pyrite was obtained by the analysis of the reflection spectra of cathode rays from natural faces of the crystal using some samples. The apparent refractive indices obtained from each order reflection show decrease at low order reflections. The value obtained for the mean inner potential and the intensity distributions in each order reflection spot which is observed asymmetrically with respect to intensity maximum, show variations with the samples. A possible interpretation for these phenomena is described.

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Strange behavior rd calcium tungstate and gold chloride in the absorption of W and AuL*, lines reported In the previous research pan the self-absorption ad some X-ray diagram lines is again observed for tungstie acid, and arrow and untie oxides. As the shifts ad the Lin absorption limits by the chemical combination seemed very small fur W and An this effect is now carefully examined her Ta, W, An and Pb absorption limits. The Lin shifts are. in v alt, +2 0 for tantalic acid, +3 0 fortungstic acid, -4 6 fair aurous oxide, -3 4 fair curie oxide, +3 4 tear lead oxide anal +6 8 fur lead peroxide From these re*ults the assmnption of the selection rule in the appearance of X-ray absorption limit is supported. and it in pointed out that in establishing the theory rd the a f -vt ad combination on the X-ray absorption limit this point will have to be taken into account in the first place. In addition t r the comparator measurements microphotometric study is alsomade, by which means a peculiar appearance of double edges Is observed in the Ln absorption limit of Au In the case of aerie oxide

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The Rayleigh waves over the circular cylindrical surface of an iso- tropic homogereous elastic b sly propagating along its axis, and espeeially the effect of the eurvature of the cylindrical surface on Rayleigh waves are investigated

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Assumptions are made that a proton air a neutron does not exist freely in the nuclei but only in combined forms of a deuton (D) or a moss tires hydrogen nucleus (T), and further that these 11 and T have tendency to unite as 3D (α-particle) 3T or D+T. The nuclei of lighter elements before Ni (Z=38) are built principally by the succesive additions of an α-particle, and in those rd heavier elements 3T additions ploy the principal role. On these assumptions plausible explanations of the number of α-particles, the mass defect curve, the abundance and occurence of isobars of elements of the odd atomic number are given. The calculation of the nuclear magnetic moments with the value y=5•0 for a proton, and g=-3• for a neutron ahows a goal agreement with the experimental values

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By modifying the bipolar transformation used by Lagally, we have obtained the complex velocity potential for the irrotational motion of an inco- mpressib'.e perfect fluid in the outer region of two parallel circular cylinders when the constants of circulation round them are given and the flaw at infinity is uniform. Ill the next place, by the aid of the Blasius' formula, we have calculated the resultant pressures on the cylinders and obtained tie expressions of the forces. In the course of the analysis, we have arrived at an interesting result that the well-known theorem of Kotta and Joukowski holds also for the vectorial sum of the forces acting on then, Moreover we have proved the conclusion mathematically that the forces on the cylinders are equal in inagnitude and opposite in sense when either of the uniform flow or the circulatory one is present. The same holds also when the algebraic sum of the circulation constants vanishes even if the uniform flow is superposed. In case when the distance of the cylinders is large compared with their radii, approximate expressions of the f, rtes have been given. Further it is ascertained that when they are apart enough, the shove expressions reduce to those when one cylinder alone is placed in an unlimited stream, as is expccted from the first. Finally we have, as examples, worked out the forces numerically for a few cases, and consideration is also male on some possible applications of this problem

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In the direetion in which the sound veiocity (inelading the cffect of the wind) in the lower medium is greder than in the upper medium, a wave of peealiar sort is produced by an explestive action at the earth surface. It is shown theoretieally the following properties of this wave, on the assamption that the two medin are homegeneons and the wave apreads out in two dimensions. (1) *It is a surfare wave in the lamer medlium travelling along the surface of separation between the two media with the velocity belonging to the upper (i) It appears only when the distance from the suree is larger than a eritieal vatue defined by 2h tanθ₀ where h is the height of the interface between the two medin and θ₀ is defined by sin θ₀=1-(T₁-T₂)/2T₂-(U₁-U₂)/c₁. Here T1, U1 are respectively the alsolate temperature and the wind velocity in the lower medium. T₂, U₂ the corresponding quantities in the upper and θ the veloecity of sound in the lower when there is no wind. Numerical example shows an agreement with Kolzers experiment. (iii) Nnmerieal value of the amplitade shows that it is observable at the earth sarface when the height of the interface is not. very large compared with the wave-length an in Kölzers experiment. Thus we identify the anomalous wave in Kölzers experiment with this wave. We have also. shown that there appears a phenomenou of maltiple reuartion showting in the direetion in which the sound velocity (ineluding the effeet of wind as befre) in the lower medima is smaller than in the upper one From our point of view, the anomalous propagation at a yreat distance-corresponds to this ease

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Ejection of alpha-partieles and induced radiontivities generated by neutron bombardmcnt are traced in photographic plates

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Emission of γ-rays under the bombardment of slow neutrons was investigated for following elements: Pb, Hg, Au, Cd, Cu, Ni, Fe and Al. It was confirmed, except Pb and Al, all these elements emit γ-rays. The cross-section of slow neutron for exciting γ-rays in Fe, Ni and Cu was estimated to be of the order of 5×10^-24cm²., while that in Cd is much larger than this value. From the fact that we could detect no γ-rays emitted from a block of paraffin 10×15×3.5cm³. under the bombardment of neutron, the cross-section for the combination of slow, as well as fast, neutron was estimated to be smaller than 0.5×10^-24cm².
In conclusion we wish to express our thanks to Imperial Academy of Japan for the grant which enabled us to cover the cost of heavy water and also to Hattori Hôkô Kwai for the grant which was used in the expenditure involved in setting up the high tension apparatus.

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The probability of internal pair production by radiationless transition of the radioactive nucleus was calculated and its ratio to the probability of emission of electrons from K levels by the same nuclear transition was compared with the experiment in the case of Rac

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