RH thermocouple is so designed that it conduct the continuous measurement of temperature up to 1, 650°C. It consists of a pair of Platinum and Rhodium at the rate of 70 and 30 per cent respectively, while minus side the same materials but at 94 and 6 per cent. This thermocouple gives the thermo-emfs of 10.718 millivolts at Palladium point (1, 552°C) and 5.623 millivolts at copper point (1, 083°C) and about 10 microvolts per deg. in the temperature range of 1, 000 to 1, 800°C.
After this thermocouple was continuously used for total 300 hours in an electric furnace with temperatures kept at 1, 500°C, 1, 550°C and 1, 600°C for 100 hours each, no crystallization of the wire was recognized and emf variation measured at Palladium point indicated only puls 4 microvolts. Furthermore, when the same thermocouple was tested again being kept at 1, 750°C for 30 minutes, 45 microvolts of emf variation was recognized at Palladium point. The above temperature of 1, 750°C is believed maximum for RH thermocouple measurement. For information, protection tube used in this test was of sinter corund.

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This paper describes a new gas flow meter which is sensitive and accurate enough to be adapted for measuring small rate of flow without pressure drop. The flow is obstructed by an inserted plate in the measuring pipe, and the produced difference of pressures at the both sides of the plate is detected by means of a thin flexible horizontal diaphragm which moves an electrode between fixed upper and lower electrodes in a water cell. The output a. c. voltage from the movable electrode, which is proportional to the pressure difference, is amplified, and drives a servomotor. Thus a positive displacement type flow meter which is connected to the motor and works as a pump, transports the gas from the upstream side to the downstream, so as to nullify the difference of pressure. The servo performs an integral action as the movable electrode with the weight balanced to the buoyancy is floating in the cell. For the stability required, a tachometer feedback loop is also provided. As results of tests, the errors of the instrument were found to be within ±0.3% in the range up to 5 litres per minute, while the pressure drop was actually at zero in this range.

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An apparatus, which is a combination of two magnetic testing apparatus, one of which has a compensating coil for the determination of magnetic properties of Si-steel 3'×6' and another with the same coil for Si-steel 2.5'×10', was designed and manufactured according to the previous report the writers made (cf. Bull. Electrotech. Lab. 19.357 (1955)). The construction of the magnetic testing apparatus and the measuring method of the iron loss are fully described in this paper. With this apparatus, the magnetization curve is obtained with about 2% accuracy by using magnetic induction up to 15, 000 Gauss and commercial frequency, while the iron loss is determined with about 3% accuracy by using the same induction up to 13, 000 Gauss and the same frequency.

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[in Japanese]

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