In an article published in the last June issue of the Journal of the Denki Gakkwai, Mr. M. Suzuki discussed at length the problem of economical constmction of transmission line. This article that deal with a part of the same subject is the outcome of the writer's effort to derive some standard value for the economical span, from the practical recults obtained in the construction of various transmission lines of the Daido Denryoku Kabushiki Kwaisha, during the past few years and its conclusions are as follows, -930ft. for 154, 000V. line, 730ft. for 77, 000V. line (suspension type insulator), and 690ft, for 77, 000V. line (pin type insulator)

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It is already well known that the theory of kenotron rectifier circuits becomes very much involved if the characteristic curve of the tube is to be rigorously accounted, and that the results will hardly allow of clear apprehension.
The circuits have been dealt with by Hull, van der Bijl, Fortescue and Duncan, generally with the aim of giving practical directions to circuit designers. They do not seem to pretend to have given any rigorous mathematical solution of the phenomena.
It may be more correctly treated by simply attributing to the kenotron the property of preventing any passage of reverse current, and assuming the internal resistance to be a constant quantity.
For half wave rectification, the D.C. voltage can be represented during the forced oscillation by the sum of exponential terms and a trigonometrical term, and during the free discharge of the condenser by exponential terms.
In the case of double wave rectification, the relations are similar to the above so long as no overlapping takes place. But if the currents through both kenotrons happen to overlap with each other, as is usually the case, the A.C. source becomes shortcircuited through kenotrons and the current through the load is again the sum of exponential terms and a sine term.
The factors relating to the suppression of ripples in D.C. voltage are discussed, the most efficient means being the use of larger condenser and higher frequency.
Kenotron rectifier circuit patented by M. Latour is finally described and is dealt with in a similar manner.

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The author has discussed the dielectric hysteresis loss in the fibrous insulating materials in his previous paper. As the fibres in the fibrous insulating materials are not complete insulator, we can consider that such incomplete fibres construct many numbers of "floating" leaky small condensers. From this consideration he reduced the following equation of dielectric hysteresis loss.
P=Σ 1/2 ω2CεEmax2/C0R(ω2+1/C02R2)
In this paper, he reduces the equation of power factor as shown below,
power factor=cosΦ=Cε/C1[C0Rω/1+C02R2ω2+Cε/C1]
In the last parts of this paper, he discusses the effects of froquency and temperature upon the Rower factor and the Dielectric hysteresis loss.

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It is disscussed in this paper that the condenser which connected to the relay contact of Tirrill-Regulator in parallel had an effect upon the exciting current and upon the spark which occurs at opening and closing of contact.
In the next place, in order to leirn the wave shapes and the instantaneous relations betwe n exciting current, induced E. M. F. and generator exciting current, many oscillograms and Broun-tube figures are taken.

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In a horizontal brass tube of length 17.8 ems. and internal diameter 1.6cm, a piece of calido wire, 0.4m.m. diameter, which was renewed for each test, was stretched with a slight but sufficient tension and a steady emf of dry cells was opplied between the two, with the negative terminal connected to the tube. If a heating current was sent through the wire, a positives ionic current began to flow from the wire to the tube electrode.
If the temperature of the wire and the applied voltage were kept constant, the current increased gradually at first and then more rapidly and began to decay after reaching a maximum. The higher the temperature within the range of the test-namely from 900 to 1260°C, or the higher the voltage from 40 to 223 volts, the shorter was the time required for the current to reach the maximum.
For a series of tests of constant voltage and different temperatures, the maximum current was the largest from the wire at about 1000°C and smaller at higher or lower temperatures. For lower temperatures say 970°C and 935°C, the current-time curves, however, accompanied another hump before reaching the larger maximum above mentioned.
For a test of constant temperature and different voltages, the maximum current was larger, the higher the voltage applied.
Characteristic curves thus obtained showed very regular forms and variations as compared with previously published results of platinum and other metals. The results were examined by pointing on. some particular features, although their explanations are not clear as is generally the case for positive emissions.

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