The authors have constructed a recording apparatus of atmospherics wave-forms specially designed for the purpose to analyse the lightning mechanism as a generator of atmospherics. As for the principles on which the present apparatus is constructed, they are just the same as those on which a sensitive apparatus to record distant atmospherics wave-forms is constructed. It is, however, essential in the former case to limit the over-all gain of the apparatus in order that the wave-form can be recorded faithfully even in the case of the st-rongest electromagnetic field change caused by a lightning discharge in the vicinity of the station. In the present apparatus the over-all gain can be varied from +40 to -50 db, hence it can records faithfully the wave-form with the field intensity from 0.3 to 5×104 V/m, using a vertical antenna of about 2m in effective height. Two cathode ray tubes of the sweep time length of 2 and 20ms are provided, with which the fine structure and the whole aspect of a wave-form can be recorded simultaneously on respective photographic films. The apparatus is equipped with an atmospheric intensity meter to know the occurrence of thunder, and several other devices to collate the records from other arrangements corresponding to the same discharge.
The Relations of advancing and receding static step voltage of single pulse dekatron to guide resistance are explained to some extent by leakage current through the guide. The effect of steepness of input voltage curve has been studied which led to a design of the input pulse shaper.
The ferroresonant flip-flops are treated analytically on suitable assumptions. The perfor-mance is explained qualitatively by a figure and the required circuit conditions are given. These are verified by experiments.
The orientation of photolytic silver from silver bromide has been investigated by electron diffraction in succession to the previous work. Different surface states of photolytic silver are obtained by various means of photolysis. There are two kinds of orientation: one is that when the  direction of the greatest atomic density of silver lattice coincides with the  direction of silver bromide, which is the rectangular intersection of  and  planes of the bromide, and the other is that when the  direction of silver lattice coincides with the  direction of silver bromide lattice or the other way round giving the best correspondence of periodicity in the atomic rows. Parallel orientations and one of  on  orientations belong to the former and the rest three orientations to the latter. The former is observed on crystals made from melt or grown form solution when heated while the latter by photolysis with ultraviolet light or electron beam at lower temperatures in connection with the forbidden spots or intermediate crystals. In the latter case, the migra-tion of silver ions toward the irregularities may be unfavored, therefore the correspondence of atomic periodicities might play an important role in setting the orientation of photolytic silver. The former case suggests the trapping of silver ions at the  direction of irregularities of silver bromide crystals.
The velocity and the absorption of ultrasonic waves (1.46MC) have been measured for 6 nylon, polyvinyl chloride, celluloid, ebonite, polyethylene, phenol resin and bakelite as functions of temperature over a range of 10_??_90°C. The velocity versus temperature curve of the first four of them has a break at the second order transition point Tm which has been determined from thermal expansion measurements. The ratio of temperature coefficient of sound velocity to cubical expansion coefficient is found to be roughly constant above and below Tm. The absorption of ultrasonic waves per unit length begins to increase near Tm. The relation between the velocity of ultrasonic waves and the density at room tempera-tures has been studied for thirty-two polymers. The plot of velocity against density shows similar features to those confirmed in the case of liquids of low molecular weight.
A method of accurate determination of crystal orientations using the back-reflection Laue pattern has been worked out and full accounts are given of its principle, procedure, and accuracy with reference to actual examples of single crystal rods of cubic iron, hexagonal zinc, trigonal bismuth, and tetragonal tin. In this method, crystal orientations are determined by calculating the inclination of the specimen axis to the crystal plane or zone axis which has produced a sharp spot or hyperbolic arrangement of spots in the Lane pattern. It is shown that the orientation determination can be made with an accuracy well within ±0.3°, using a comparatively simple X-ray camera.