As the study of the subject, various methods such as Russau Diagram, Russel angle method. etc. are well known.
The diagram method is generally used as a standard, and the measuring of the distributed flux of the incandescent lamp, etc. is commonly tried by the use of a bench photometer. In this method. fixing a polnt between the test lamp and the standard one, where the illumination is equal and thus determining the distances, among them, we can calculate the mean spherical candle-power under inverse square law by using a planimeter or other instruments.
But in this paper, the author tried to introduce a new method to estimate the mean spherical candle-power. That is, in this method, if the ratio of the above two distances is kθ, the angular relation are a=(1-cosθ)·π/2 (θ is inclination angle from the perpendicular axis), and the point kθ are put on the α line as the polar co-ordinate, the area of envelope of curve, which consists of these points is proportional to the total flux of the light source or the mean spherical candle-power. Moreover, we made the approximate formula and angle transformation table.
This method depends only upon the ratio of distances. Moreover, it is superior to the convention one in accuracy but easier to do.

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Although in the precise measurements, a fluorescent lamp should be controled at a rated lamp wattage, it has also some advantages to control it at a rated lamp current in the practical measurements.
The authors compared these methods on the following factors:
1. Measuring instruments to be used,
2. difficulties of the measurments,
3, effects of the impedance drop at the rated lamp current, and of the material and saturation characteristics of the used choke coil,
4. effects of the frequency and the voltage wave form of the power source,
5. the relation between the percent variation of the luminous flux and that of the lamp wattage or amp current.
From these experiments the authors recommend to control the lamp combined with a proper choke coil at a rated lamp current for the practical measurments, and propose a specification on the power source and conditions for the measuring circuit, in order to obtain the unified luminous flux and electrical pararneters on fluorescent lamps among the industrial laboratories. Deformation of the wave form in each parlf of the measuring circuit due to the characteristics of the used choke coil is also discussed.

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The Electroluminescent layer is made by the dispersion of phosphors into the layer of dielectrics. It is essential in produing the EL panel to find the adequate thickness of the EL layer and the phosphorous concentration. Our research is limited only to the problem of the brightness of the EL panel. The change of the brightness caused by the change of the thickness and phosphorous concentration is measured and theoretical considerations lead us to series of equations explaining the phenomena.
Results thus obtained are:
(1) From the reflection and absorption of light caused by the EL layer we can obtain equations connecting the brightness with the layer thickness.
(2) The change of the phosphorous concentration causes the change of the internal electric field of the phosphors: This consideration leads us to the equations connecting the brightness with the phosphorous concentration.
These results coincide with those of the measurements.

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Hue discrimination steps of spectral colors were determined. Determinations were made (1) varying dominant wave-length at several degrees of constant purity and (2) varying purity at several dominant wave-lengths. The apparatus used was the one reported in previous report which was slightly modified to meet this purpose. The white light mixed up with spectrum light was approximately at 2700°KK or 5100°KK.
Hue discrimination curves hue discrimination steps versus dominant wave-length charachterizecl by two minima, which became smoother with the diminution of purity.
Generally speaking, discrimination steps increasaed with decrease of purity, but the enhancement was not uniform; for some dominant wave-length, 450 nm, for instance, they showed apparent minimum at low purity.
The numbers of corlors discriminated at low purities were also calculated and reported.

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