Authors, both engineers of the Inawashiro Hydro-Electric Power Company, describe some notable results of Seven years' operation and maintenance of their companys' transmission line. The line which is double circiut, 115 K. V., 140 miles in length, is the pioneer of high voltage and long distance transmission in Japan. It has been successfully in service since the end of 1914.
The max. power delivered at the receiving end amounted to 51, 000 K.W. by the aid of two 7, 500 K. V. A. synchronous condensers installed at Tabata Receiving Station Tokyo.
The telephone lines are run on separate wood poles along the main line.
Along the transmission line there ara 23 patrolman stations about 6 miles apart with each other and a telephone booth between every two stations. Each station is equipped with a small warehouse and stationed by two patrolmen who patrol the line everyday.
In regard to line troubles, a complete table is given classified according to their causes such as error in operation, insulator failure and defective material etc. The insulator fialure is the predominant cause of line trouble. In early part of the operation the insulator failed to direct puncture. but now a day there are only few flash overs.
A study was made on result of lightning observations made at different points of the line and opeiating record of lightning arrester. Authors show that tlrre is a certain relation between insulator trouble, air temperature and lightning.
Informations as to testing the insulator and replacing weak insulators are shown in detail, A crew consisting of one foreman one megger man and two linemen, goes over the whole transmission line twice every year, The crew can test 900 to 1, 100 units daily and the expence is about 1cent per uint. The description is made also about the work of the insulator replacing crew. The Company make use of cap and pin of defective insulator over again. The paper treats with the method of cementing, testing and packing etc of insulator.
It has also been noticed that galvanization of groundwire and such tower materials as forged members and bolts is remarkably attacked especially near Tokyo, where smoke from various chemical industries is abundant.
In conclusion dscription is given on the expence of every details of line maintenance. The total maintenance cost averages nearly $ 600 per mile per year or one tenth of cent per K.W.H.

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The author treated the sensitiveness of Thomson's method for the measurement of galvanometer Resistance. And it was concluded that the best condition can be obtained when
(a) Q: S is as small as possible,
(b) P: Q is as large as possible,
the resistance of the battery circuit being independent on the sensitiveness. (See: -Figure 3)
And the method was compared with Wheatstone Bridge Method, which, if the current thro' the galvanometer under test be limited as well as the former, is not always superior to the former.

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In this report, the writer poposes a new methol of delineating the wave forms of radio frequency currents in an oscillation circuit by means of a Braun tube, the cathode-ray oscillograph.
The method of wave form analysis with what is called "cyclic current diagram" was originally invented by Prof. H. Yagi in 1916, and has been used for the purpose of obtaining the wave form of high frequency current by taking the diagram which is described on the fluorescent screen by the cathode-ray beam under the deflecting actions of the current i and the terminal voltage of an inductance or L di/dt in the orthogonal directions to each other. This method is, however, insufficient for the exact delineation particularly for the interval when no current, variation takes plaee or di/dt=0.
Besides cyclic current diagram, the new method requires what the writer will call "integral current diagram", which is obtained by the combined actions of current i and the terminal voltage of the condenser or 1/C∫idt.
Although this method is a little more tedious and is applicable only to high frequency currents in condenser circuits, it is very exact and when the apacity of the condenser is known, we can determine not only the wave form, but also the time intervals exactly, and consequently we can calculate out the frequency of the current.
As an example of this method of deliueation, are oscillations are studied experimentally for the special case where the oscillation circuit has no resistance. In this case, the are hysteresis can be obtained indirectly from these two diagrams.
This report includes the following topies;
I. Introduction-Cathode-ray oscillograph
II. "Integral current diagram"
III. Are oscillations
(a) wave forms of oscillating currents
(b) dynamic characteristics of the oscillating arcs
IV. Conclusions Literatures.

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TLe construction of an artificial three phase power transmission line 400 kilometer long is planned at Electrotechnical Laboratory to study the transmission line phenomena. To perform the special study of the pheno mena of arcing ground, the operating voltage is decided at 3, 000 volts Yor 5, 200 volts between lines.
The condensers, which are the most important part of the artificial line, are all constructed at the Laboratory. This paper describes the process of manufacture of the condensers and the test date.
For the dielectric of the condenser, ordinary plane window glass (thickness average 0.2 cm) free from air bubble is used. We used the electrolytic copper plate 4 mils thick as the coating, and the whole mass of the conde- nser proper is impregnated with commercially pure paraffin.
All of the condensers are tested with 10, 000 volts 50 cycle alternating current for one minute. When the insulation resistance between the terminals and between the coating and the case is tested with a 1, 000 volt meggar, insulation more than 2, 000 megohms are shown for all.
The total number of condensers constructed is 1, 010, by measurement with 50 cycles the valuos of capacity ranging from 0.01300μ.F. maximum to 0.00950μ.F. minimum and 0.01110μ.F. average are obtained.
The discrepancy of magnitude of the capacity is presented in the form of the probability curve.
Puncture voltage tested for the giass plate was made upon 10 speeimens using the electrode of circular disc of diameter 3 cm., thickness 1 cm.
The results of measurement are 58, 000 volts for the maximum value, 34, 600 volts minimum and 43, 800 volts average.
After the completion of foregoing test, two of some condensers, when they are tested under 50 cycles alternating current pressure give puncture voltage of 32, 000 and 26, 000 volts.

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