A small Nier type mass spectrometer for the use in high vacuum is presented. This mass spectrometer has the ion orbit radius of 15 cm, the deflection angle of 60° and the resolving power of about 120. The analyzer tube consists of entirely glass made envelope, the inner surface of which is silver-plated. In the electrical power sources new designs are applied, and some of them are as follows : first, in the electromagnet current regulator, (1) the magnet current is regulated by a circuit where transistors are used incombination with ordinary electron tubes, (2) the magnet current is swept in such a manner that mass numbers have the good linearity with time, and (3) a mass number can be returned back by a small quantity at any instant. Second, in the ionizing current regulator, the ionizing voltage is kept constant by using a transistor
Detailed descriptions of the theory on the linear approximation of the sweeping mass numbers are made. The magnet current is swept by a capacitor-resistor discharging circuit. Conditions for the most suitable approximation are given in a table.

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The vapor deposited thin metal film is known to be different from the same bulk metal in its properties in many cases.
Therefore, since the properties of the thin metal films are not obtainable from bulk metal directly, the thin metal film must be produced at first for perusing these properties.
This paper briefly shows the process producing the thin metal resistive elements by the vapor deposition method and then presents the various characteristics obtained from the sample which are, the nickel-chromium and the chromium thin metal films deposited on the hot micro slide glass substrata. These samples are produced for the purpose of miniaturizating electronic components.
These characteristics are summarized as follows
(1) When the artificial aging by heating is given at 200°C, the resistance changes [ΔR/R (25°C)] of both the nickel-chromium and the chromium film increase rapidly with time up to 10 hours, then both of them show almost saturated characteristics. And it can be said for both nickel-chromium and chromium films that the resistance change are smaller for the thinner films.
(2) When the artificial aging by heating is given at 300°C, the resistance changes versus time of both the nickel-chromium and the chromium films are such that the characteristics varies from semiconductor type to bulk-metal type as they become thicker. For the extremely thin films, they become open with considerably short time, and this peculiarity is likely to occur for the case of nickel-chromium films.
(3) For the given value of resistance, the chromium film artificially aged by heating at 300°C shows smaller temperature coefficient than the chromium film aged at 200°C. As the matter of fact, the resistive element consisting of chromium film aged at 300°C, with the excellent temperature coefficient of 10^-5/°C order for the temperature range of -42°C to +130°C was obtained in the experiment.
On the other hand, for the nickel-chromium films, it may be concluded that the resistance elements having the almost zero temperature coefficient can be produced by adjusting the film thickness properly.
(4) In the other tests such as the voltage dependency, resistance noise characteristics and resistance change before and after the temperature cycling etc., chromium film showed better results in comparison to nickel-chromium film.

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