A 3. 5-meter integrating sphere has been investigated concerning the effect of the length of a fluorescent lamp, the difference in the spatial light distribution of lamps compared, and the difference in the light absorption by lamps themselves. With regard to heterochromatic photometry a monochromatic comparison between the flux emitted by a fluorescent lamp and that given by a standard tungsten lamp is made in the integrating sphere, to avoid the difficulty of correcting the physical photometer so that it may have the same spectral response as the average eye. In this method, the correction of the errors caused by the slit-width of a monochromator is discussed.
Though it is recommended that measurements on fluorescent lamps should be carried out at a fixed ambient temperature, the means of exactly specifying the ambient temperature conditions have not yet been developed. Therefore the temperature distribution in the integrating sphere has been measured.

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The color rendering of a light source is assessed by means of color shifts of representative surface colors under the test light. This paper describes a photoelectric instrument which enables us to read directly specification of the surface color illuminated by any light source.
The measured values of x, y and Y are converted into the Munsell renotations, then the color distortion or the color shift can be calculated. The evaluation of the color rendering properties of fluorescent lamps thus obtained is equivalent to the results of the tiresome calculation mentioned in the previous paper.

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