For the purpose of carrying out the colorimetric measurements of various light sources including flu orescent lamps, a tentative model of dispersion-type photo electric colorimeter combining the prismatic dispersion system and photo-electrisc cell, has been developed and built by the author as a unit using a physica I method other than visual photometry.
In the conventional type colorimeer using the fitter and photo-electric cell, there is an extrrme difficulty in making the sensitivity resulting from superposition of the prismatic characteristic of the filter over that of the photo electric cell accaraftly conform to tristimulus values specified by the C. I. E.
Under such circumstances, an approximate characteristic curve is available at best, making it impossible to perfectly convert results to the X, Y, Z system.
By the proposed system of dispersion, such defect can be eliminated and the measurement results will be more reliable than before, it has been confirmed.

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This is a part of the t-tudies of determining lines of the same colors on a ball. As wood is not so homogeneous as plaster, metal and galvanized surface, owing to its fibres, annual rings and pith strings, the following method has been adopted. The report is to reveal the result of an experiment made on the relation between the angle of incidence of radiating light and intensity of reflected light, with twelve kinds of timbers generally used in Japan, by gradually turning the wood surface, by means of the apparatus of photo electric tube. On a planed surface, the intensity of reflected light generally increases with the decrease of the angle of incidence, but when the direction of fibre is perpendicular co the axis of rotation, the plane takes an aspect of a quasi-polished surface, especially the trend is conspicuous when pith strings are exhibited as a plane. When the direction of the fibres is parallel to the axis of rotation, the intensity is high in case that the direction of the annual rings is perpendicular or parallel to the direction of radiating light. Diminution of the degree of lustre with the lapse of time makes the surface rough and coarse. The surface planed with emery-paper or a file tends to become a coarse surface, and through the Nicol's prism it also is learned to be allied to a surface of diffused reflection.

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