This Paper has been presented on the First meeting of the Institute of Electrical Engineers of Japan held in November, 1925 and is described especially on the latest development of the carrier telephone system on telephone lines. The writer points out the merits and dimerits of the various carrier telephone systems of Western Electric Co. in America, Telefunken A. G. and Lorenz A. G in Germany. Moreover, this paper contains the elucidations about the necessary requirements on the conditions of the lines, in Which the carrier telephone system is to be applied, and also the test results on the Tokio-Osaka telephone line, in which the carrier telephone system will be recently provided with. At the end, the application of this system is discussed from the economical standpoints.

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Communicati u test on short waves across the Pacific was carried out in order to see what wave length should be used for Trans-Pacific communication and to find the wave length which gives the signal strength at a certain distance both at night and in the daytime.
The 500 watts short wave transmitter was installed on board S. S. Shinyo Maru for that purpose, while the short wave transmitters of the Training School of the Departmcnt of Communicatons, Shiba, Tokyo, of Iwatsuki Radio Station near Omiya and of Ottishi Radio Station near Nemuro were utilized for the transmission to S. S. Shinyo Maru.
The wave lengths of these stations were as follows;
Transmission was done two or three times a day by each station, so that we should be able to compare the daytime and night transmissions.
S. S. Shinyo Maru left Yokohama on Feb. 21 and arrived at San-Francisco via Honolulu on March 8th this year.During her voyage the stations concerned sent test signals as scheduled which were received by others every day. During her homeward voyage from the departure at San Francisco on March 17th to the arrival at Yokohama on April 2nd, We made the same test.
The signal strength measured every day were plotted against distances, from which we find the following facts;
(1) 40.5 meter wave may be used with fairly good result for the whole range up to 8400 kilometers at night.
(2) 21.5 meter wave is far better than 40.5 meter wave for daytime transmission.
3) Skip distance phenomena is remarkably shown by the audibility curves, and (i) The shorter the wave the more skip distance we have. (ii) The shorter wave skips more at night than in the daytime.
(4) For a certain distance there is one wave which gives the same signal strength both at night and in the daytime. From the curves we got 21.5 meter for 3100km., 30 meter for 1500km. and40.5 meter for 520km. A curve is drawn from these data showing a relation between the distance and the wave length, which is very valuable for choosing the wave length to be used for a certain distance. It must be noted that this curve is good only in this season(February 20 to April 2)of the year. Probably the curve will be lowered in summer and raised in winter, becau e the shorter wave is suitable in summer and the longer wave in winter, which fact was evidenced by our short wave test of more than one year.

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The auther succeeded in applying photo-electric cell for practical photometry.
A good screen was made by potassium bichromate, avoiding an error caused by color selectivity.
Illumination measurement seems hopeless, because it is very hard to get a component in any direction, for examples, horizontal illuminaton.

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Moll's thermopile of "small surface pattern" made by Cambridge Sci. Inst. Co. was tested in our laboratory. Its direction characteristics peculiarly deviate from cosine law, for active elements are arranged in straight line, not having point-symmetry against its window, and moreover conical reflector makes the sensibility more directive. Several test-results about reflector are also described.

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Assuming that the electrons by which the electrical conduction in dielectrics is carried out, are of thermionic origin, the number of these electrons in unit volume is given by Richardson's formula in the case of thermionic emission. Considering the recombination of electrons with the parent ionized atoms, we deduced the number of electrons which actually convey the electronic conduction, and thus obtained the expression for the electrical conductivity as a function of temperature and of material constants.
Comparing this expression with my former experimental results for quartz, a good coincidence between the theoretical and the experimental results were obtained, and thus, for quartz, the theoretical curves expressing the variation of the electrical conductivity due to temperature agrees satisfactorily with the experimental curves, up to a certain high temperature; and also reasonable values for the acting radius of the atoms in quartz and for the equivalent potentials for the emisson of an electron from the atom in quartz were deduced. Puttingφ=hv, we also deduced the natural frequencies and its wave lengths for quartz plates, one cut parallel and the other perpendicu_??_ar to the optical axis; these values fall also within the range of values actually observed by Listing and by H. Rubeus and Nichols.

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The equivalent network of the balanced polyphase induction motor has been discussed by many authors, but those of the unbalanced induction motors have never been discussed, except some special cases, as far as the author knows.
The author reduces the equivalent networks of the unbalanced induction motors of the following four cases.
1. Case of the unbalanced voltages impressed upon terminals of the poly phase induction motor.
In this case the primary current is the resultant of two current vectors, Which can be obtained by the equivalent circuits of two balanced induction motors respectively. The current locus of the primary current is not a circle, but becomes a hither algebraic curve called "Bicircular quartics".
2. Singh phase induction motor.
Single phase induction motor is a special case of the case 1., but the author treated separately & reduces the equivalent network The current locus becomes also, a curve of "Bicircular quartics", which in this case approximate1y becomes a circle.
3. Case of the unbalanced external resistauces added to the secondary phiase windings.
The author reduces the equivalent network & the current locus of the primary current by solving differential equations to this case.
The primary currents divided in two symmetrical components, both describe higher algebraic curves, the one has the same frequency with that of the supply voltage, & the other has a frequency of (28-1) times the frequency of the supply voltabe, where 8 is a slip.
4. Case of the polyphase induction motor with single phase secondary winding.
This is a special case of the case 3., & this is known as Görges' Phenomena.The auther reduces also the equivalent network & the current locus.

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