In the present paper the authors describe the results of experiments on the effect of electric discharges upon the rate of growth of certain plants. The currents applied are of three kinds, viz. high-tension A. C., high-tension D. C. and high tension high-frequency current. The experiments were carried out, since 1921, in the Botanical Garden of the Tokyo Imperial University.
Field experiments on the electro-culture have hitherto given no consistent results, some workers reporting a considerable increase in crop production, while others stating no such effect. The authors conducted their experiments in a green house so as to keep culture conditions uniform for both the electrified and control plants. The electric current of very low intensity was induced in the plants by applying high voltage to a thin wire net-work suspended at a distance of 15-30cm above the plant. The determination of the result was done by estimating the dry weight of plants, grown as fully as possible under the conditions of experiments.
Preliminary tests with high-tension A. C. Several kinds of plants were treated with high-tension A. C. of 50 cycles and at 21, 000 volts. The electrified plants have shown mostly an accelerated growth. For instance, the two series of experiments with buckwheat showed the average increase of yield amounting to 9.8% and 8.0% respectively for the electrified.
High-frequency current experiments. High frequency voltage was produced by a set of three quenched spark-gaps in series. The fundamental frequency of the wave was about 130, 000 cycles and the E. M. F. measured with needle point, spark-gaps was about 13, 000 volts (crest value-spark distance being 1.5 -1.6cm.) The results obtained were not uniform, but in a recent experiment the electrified buckwheat gave the yield 12.6% greater than the control.
High-tension D. C. experiments. High-tension D. C. was obtained by rectifying 50-cycle A. C. by means of a kenotron. The aerial net work was kept as (-) pole while the plants (+) pole and the voltage was held unchanged in some cases, but in others controlled within 10, 000 and 15, 000 volts (effective, measured at A. C. side, ) so as to keep the current passing through the plant nearly same. The first few experiments did not show much differences in the growth between the electrified and control plants. But the effect upon tobacco plants was rather conspicuous, as may be seen from the picture shown below, the increase in dry weight being 21.70 of the control.
Experiments with the coleoptile of oat. Besides the culture experiments above mentioned, the authors have made more minute observations on the change of the growth rates of coleoptile of oats under the influence of electric discharges. The temperature of the dark chamber in a thermostat was kept constant within a range of 0.01°C. A charged point of platinum wire was fixed at a distance of 30mm just above the plant. The rate of growth was measured every 5 minutes with a horizontal microscope which was illuminated by weak red light only while taking the reading. The results of experiments are shown in curves 1-32. From these it may be concluded:
1. The control test shows that the normal growth rata of coleoptile is quite uniform. (See Curve 1.)
2. The three kinds of electric currents show the effect of almost the same nature, viz. "immediately after the discharge the growth rate diminishes, but after about 15 minutes tends to increase and attains a maximum in about 1/2-3/4 hour, often reverting to the original rate after 1-2 hours." The phenomena observed may be appropriately termed "the electro-growth reaction."
3. It seems that a certain voltage at a certain distance between the poles gives the maximal growth effect.
4. The observed change in growth rates is due solely to the electricity applied, although the authors are not yet certain whether it is caused only by weak electric current passing through the plant or by some ionic actions.

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The paper describes an arrangement for maintaining constant the value of a resistance (see Fig. 1) which forms an arm in a Wheatostone bridge supplied from a source of power cycle. The unbalanced voltage due to the change of the resistance appears in the galvanometer circuit of the bridge, this voltage controls the arrangement which in turn adjusts the current supply to the bridge. The author names the arrangement an a. c."polarised" relay since its action when the variation of the resistance is positive must be quite different from that when the same variation is negative. Various modes of obtraining a. c."polarised" relays are discussed. The method finally adopted is an follows. After two stage amplification, the unbalnced (input) voltage is applied to the grid of two detectors whose plates are supplied with a. c. voltage derived directly from the bridge source. The detectors are connected in "push-pull" and in their output oircuit is included a d. c. polarised relay. This relay controls in the usnal way the current supply to the bridge.

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The following paper describes the results of experiments carried out by the author as an application of the electroscope method introduced by Prof. A. Schwaiger for measuring electric field and elucidates the results as applied to a model of a three-phase cable to show that the method is quite practical and accurate for the purpose of measuring electric field in general and at the same time the author intends to illustrate the configuration of the lectric field in the three-phase cable and tries to find out simple mathematical expressions for maximum electric stress, especially for the tangential stress, possible to occur in the dielectric of a three-phase paper cable.
Important results obtained from the research are as follows:-
1. The Schwaiger's "Electroscope Method" is a suitable one for the experimental solution of determining the distribution of lines of force in a complicated electrostatic field and gives accurate results (the experimental error can generally be expected to be less than 1%).
2. From experiments it is established:-
The maximum normal stress in the paper insulation of a three-phase paper cable is given by the formula (A) while the maximum tangential stress will be given by the formula (B). Therefore, the ratio between the two stresses is expressed by the formula (C),
where Vmax=the maximum potential of a conductor against the earth.
r=the radius of the conductor
m=ratio thickness of insulation/diameter of the conductor.
Thus the smaller the ratio, thickness of insulation around the conductor to its diameter, the more necessary it is to take the tangential stress into account in designing the cable insulation. Further the value of k given by the formula (C) is such that it should always be taken into account, because the tangential dielectric strength is far inferior to the normal dielectric str ngth of the paper insulation of the cable.

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In this paper the author describes a new type of low voltage electrostatic oscillograph which enables to record oscillogram of sufficient amplitude of A. C. voltage about 100 volts or less supplying D.C. voltage less than 300 volts.
This oscillograph is a modification of the Ho's electrostatic oacillograph, and in order to increase its sensitivity the distance between plates is made very short using solid insulating materials attached to the insides of both plates.
Further, he explains the connection of the vibrator to obtain correct wave form and the means to minimize errors due to unsyminetrical arrangements of the vibrator.

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This instrument has been devised for the purpose of reeording the relation between two given varying currents, as a two-dimensional figure. With respect to its principle, it is an electromagnetic oscillograph of a moving coil type. It has two single loops of four conducting strips being stretched between two guide pieces of ivory with peculiar grooves, in a strong magnetic field. Very thin and flexible cross fibres are bridged over the strips of both loops midway between the guide pieces, and a very small and circular mirroris cemented at the centre of the cross fibres. The mirror will be caused to vibrate around two rectangular axes simultaneously, by currents passing around the both loops. The current sensibilities of some vibrators recently constructed are in the range of O.2-2m.A. per mm. of deflection at one meter scale distance, and the natural frequency is about 2000 cycles per sec. For some fundamental loads, loci and areas of their cyclograms in relation to power or reactive power lost in the loads have been discussed, and finally many actual examples of cyclograms explained.

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When an electric motor is started from standstill at no-load the torque developed is consumed mainly by the inertia of its rotating parts and the angular acceleration is approximately proportional to the developed torque. The authors connect a moving-coil galvanometer through a series resistance to the terminals of under test, thus obtain deflections proportional to the speed.
Another galvanometer of the same type connected to the dynamo through a suitable condenser gives deflections proportional to the torque. By combining these two deflections together at right angles, a spot of light falling on a photographic plate describes a curve which is similar to the torque-speed curve.
The output-speed curve is obtained by replacing the second galvanometer with an electrodynamometer, the fixed coil of which is connected through a series resistance, while its moving coil, through a condenser, to the dynamo; thus the turning moment of the electrodynamometer being proportional to the speed times angular acceleration. Input-speed and current-speed curves are obtained by combining a reflecting wattmeter and ammeter resectively, connected as usual to the supply main, with the reflecting galvanometer which indicates speed. The curves given have been obtained by experiments carried out on a 71/2H.P. 3-phase induction motor with squirrel cage rotor, provisional instruments critically damped being used throughout.

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