This paper is the report of the television experiment conducted in April, 1927. In the television system a perforated revolving disc (Nipkow disc) was used as an analizer of images at the sending side and a Braun tube was used on the receiving side. A special synchronizing method of both sides was used.
The received image can be seen on the fluorescent screen of the Braun tube and the size of the image was about 4cm. square. The number of picture elements of the transmitted image was about 1, 600. The images were, reconizable as faces, but identification was hardly possible.

View full abstract

As an introduction to the subject, the author deals with the two physical bases of the charging-up of dust particles in the electric precipitator. Of the two, the first is based upon the heat collision of ions on the particle as pro posed by the original theories of Deutsch and Seeliger, and the second is ba sed simply upon the collision between the ion-stream and the particle surfa ce exposed to the former. After some theoretical considerations, the aut.or concludes that for particles smaller than 1.10^-5 cm radius, the charging process is mainly of the first nature, while for those larger than 1.10^-5 c.m. radius, the process is solely of the second nature. Hence, for the small particle, the amount of charge depends upon the time of charging for given ion density, but not upon field strength, while for the large one, the amount increases with field strength and the time necessary for full charging is very small in usual current density.
The above theoretical conclusions are confirmed for large particles, say ce ment dust, experimentally by observing the space-charge effect caused by the charge of particles upon the discharge-action of the discharge-electrode in the precipitator, that is, the length of the precipitator and the velocity of the gas in it are chosed as such magnitudes as to protect the precipitating action of the charged particles during their passage through the precipitator, and the decrease of discharge-current caused by the introduction of dust par ticles into the precipitator is measured for various discharge voltage, particle density, electrodes-size, and time of charging. The results clarified the nature of charging process as shown by the theoretical considerations.
Some other experimental results are also given to show the effect of such nature of charging process upon the actual precipitation phenomena according to the particle size and to obtain some means for improvements on precipita tor design.

View full abstract

In this paper, a direct and absolute method of measurement of so-called electro-acoustic pressure ratio of the electro-acoustic instrument is described In this method, the sound pressure acting on the mouth of the instrument and E. M. F. induced in it are measured respectively by a vibrometer provided with a specially prepared diaphragm and a vacuum tube voltmeter

View full abstract

The present paper describes about the principle and actual construction of a special potentiometer which enables us to read off directly the pH value of a liquid under test, without any calculation, at any temperature between 10°C-30°C.
A special double slide resistance S₁S₂ is inserted between the measuring part Q and the parallel resistance P of the measuring part, so constructed that toward Q, S₁S₂ operates as a double slide and toward P, it operates as a single slide S₁ only, The values of S₁ and S₂ are so chosen that the total current i of the potentiometer circuit does not change, though we can change the current i₂ of the measuring part continuously or discontinuously, i. e. in any way, according to the room temperature t between the range above described.
The principle seems to be useful in a wider field of electrical technics than in the limited of the measuring instruments.
The actual construction is explained in some details. The instrument will be of use also in the following departments of science-electro-chemistry, physiology, etc.

View full abstract