The thermal and electrical conductivities of Cu-Zn alloys (0 to about 50% Zn) were measured at 0° and -195°, and their behaviours in relation to concentration were studied. The relation between thermal and electrical conductivities, and the characters of Lorenz-ratio of these alloys were explained on the basis of the Authors' conception formerly reported.(i) The temperature dependency of thermal conductivity of these alloys was also interpreted.

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The thermal and electrical conductivities of 6 kinds of commercial heat-resistant alloys were measured in the boiling nitrogen bath. From the present results and. those obtained previously at high temperatures, the following facts were derived. (1) The temperature coefficient of thermal conductivity is positive for these heat-resistant alloys. (2) Whereas Lorenz-ratios converge a little larger value than the theoretical one at high temperatures, they increase larger at lower temperatures. (3) The thermal conductivity of one of them (Ni-Cr-W-Steel) is nearly 1/100 of that of copper at the same temperature.

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A new powerful X-ray tube has been devised. It has a rotating target cooled with water and sealed with mercury. The mercury column is divided into three parts in order to shorten the height of the tube. As the mercury vapour is settled under cover of an oil of small vapour tension, the tube can be operated as a hot cathode one. The tube here described has the following merits:
(1) The rotation of the target can be conducted very smoothly and with a comparatively small power.
(2) The construction of the tube, especially, that of the water-cooling-device is comparatively simple.
(3) The tube has no fragile part, such as the packing, the metallic sliding part, etc.
Hence this tube is very useful for the metallographical research of short time exposure, such as the study of the progress of a transformation, the special high temperature camera, etc.

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Difficulty is frequently experienced in obtaining accurate result in the determination of molybdenum in metals and alloys by the method based on the separation of MoS₃. According to the Author's experience, the chief source of error ought to be an errornious adjustment of the acidity of the solution, taken before it is precipitated as MoS₃. For instance, in the case of the precipitation in an acidic solution, if the solution is too slightly acid, H₂S treatment causes a deep red coloured colloidal state of MoS₃ in it, on the other hand, when the solution is too acid, the partical precipitation is obtained together with a blue colouration of the filtrate.
There are many papers published already on the special acidity in the MoS₃ precipitation, but to know the safty range of acidity in which the precipitation goes to completion is highly disirable.
In this paper, the result obtained about the range of acidity for the complete precipitation of Mo in the form of MoS₃ from an acid, or alkaline solution followed by dilute acid, with or without increased pressure, are given.

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Adding a small amount of the following each element, Ag, Bi, Co, Cu, Fe, Mg, Mo, Mn, Pb, Si, Sn, Ti, W or Zn, to the aluminium-raffine, the mechanical and electrical properties as well as the corrosibility of the alloys have been studied. The results obtained may be summarized as follows:-
The addition of Cu, Mg, Si, Fe and Ti increases the tensile strength of the aluminium more markedly than the effect of the other elements. The elongation of the aluminium decreases generally as the amount of added metals increases, with an exception of the addition of Bi and Co, wihch improves the said property. The elements which markedly decrease the electrical conductivity of the aluminim, were found to be Ivln, Ti, Mo and W. The effect of the addition of Fe, Ag, Cu, Si, and Zn is not notable. While Pb, Bi, Sn and Mn improve the corrosibility of the aluminium, the addition of Ag, Zn, Cu, Ti and Fe gives deleterious effect.

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The problem of internal friction of metals are of practical importance in the research of dynamic properties, strength, and internal structure of metals. This paper shows experimentally that the internal friction of some carbon steel decreases with the decrease in amplitude, and this decrease is more rapid at smaller amplitudes. The internal friction for larger amplitudes, however, is more nearly constant and is subject to the laws proposed by Kimball and Lovell. This result approximates Ockleston's recent result with regard to mild steel. Also this paper shows the theoretical treatment of Searl's system of vibration following the laws stated by Kimball and Lovell. Moreover the theoretical treatment of clampled-free rod vibrating laterally is also shown in the same case.

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