In order to perform the automatic cascade test, the velocity head and yaw angle must be known by the automatic follower. The velocity head follower was based on the on-off positional control system with the detector which followed the height of the meniscus of the water manometer. The detector of the velocity head follower was consisted of one light source and two CdS cells and faced each other across the glass tube of the manometer. If both cells were lit through the water part, then the detector was moved upward along the glass tube until one of them was lit through the air part. Similarly, both cells were lit through the air part, then the detector was moved downward until one of them was lit through the water part. The detector of the yaw angle follower also had the same elements. However, it was not moved by the height of the meniscus, but the arrow head type yaw meter was rotated by motor on-off controlled until the differential pressure became zero in the U tube differential manometer. These data (the velocity head and the yaw angle quantities) were transformed to the electrical signals and then substituted to the automatic computer whose output were shown numerically the energy loss coefficient. In our first report the automatic follower were described and in the second the automatic computer will be treated. The features of the follower was followed; (1) Accuracy of velocity head about 1% at 20-60m/sec, (2) Error of yaw angle about 10min, at 40m/sec, (3) Following speed of detector 0.7mm/sec.

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When the current or the voltage whose form factor is not equal to π/2√2 is measured with the rectifire type indicating meter, an error is caused. The error for the current expressed in the form of i=I₁{1+a_nsin(nx+φ_n)} is maximum or minimum in the next conditions. n odd: φn=0 & φn=π, n even: φn=0 & φn=π/2. Errors in these cases have been calculated and shown in Fig. 3, 4 & 5. When an is small, the error in the case of even harmonic is smaller than in the case of odd one, but is not equal to zero. When n is larger than four, the value of the error is maximum and is about -10% when an in nearly equal to one.

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According to the recent development of electric insulation materials, there has been an increase in demand for an sensitive megohmmeter To meet the above demand, we have developed an electronic megohmmeter (Type RM-211) which, by impressing 1000V DC on an unknown resistor, can directly read its insulation resitance from 5×10⁷Ω up to 2×10¹³Ω with better accuracy, more stability and for simpler operation than any coventional galvanometer device can provied. In this paper, the description has been made on how to stabilize DC Amp. and DC high voltage source as well as how to get an extremely high input impedance of said DC amplifier. Also the upper sensitivity limit of this method has been discussed.

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As means of performing quality control for W-filaments in their progress of production some equipments have been designed up to the present. Yet auther perceived about the method of infering from non-uniformity of W-filaments from the state of fluctuation of electrical resistance per unit length along the W-filaments, and produced by way of experiment the continuous resistance measuring device for fine filaments such as tungsten filaments. The device is constructed with mercury electrodes to detect the electrical resistance continuously, narrow-band amplifier to cancel the disturbances from stray electric or magnetic fields and the input of which is formed as the bridge circuit to compensate errors caused by the variation of temperature surrounding and recorder to record the fluctuating portion of resistance. As a result of many experiment auther conclued that this equipment might be useful in quality control for W-filaments.

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