Heterochromatic brightness of colored samples is measured with Munsell value scale standards. The samples are divided into two groups: one is of medium luminous reflectance and the other of high luminous reflectance. Contour lines of the ratios of observed heterochromatic brightness L to luminous reflectance Y are drawn on C. I. E. (x-y) chromaticity diagrams by inter-and extra-polation methods. The differences between the observed data and the data obtained in previous investigations are found very small in the direction of -β axis. This is considered explainable on the one hand by the displacement of luminosity curve and on the other by the theory of color vision that the sensitivity of three receptors are non-linear in color perception.
In the preceding paper, starting from the Herzberger-Focke's fifth order aberration theory, the author has defined the new practical aberration coefficients, which correspond to the Berek's coefficients in the region of the third order. In this paper, the various formulas of the aberration coefficients are considered. The contents are: Relation between the aberration coefficients of image and those of pupil; shifting of pupil and object; curvatures of object, image and pupil surfaces; relations between the intrinsic and the total aberration coefficients; and the aberration coefficients based upon the exit pupil coordinates. Most of the formulas are derived from the Herzberger's theory, but some of them are supplied by the author. Every transformation formula may be applied to both the intrinsic and the total aberration coefficients of any rotationally symmetrical system.
In Part I1), one of the authors showed that the homogeneity of optical glass could be tested by measuring the astigmatism by Ronchi test. In this report, examples of testing are given for which the following types of glass are selected and tested. Normal astigmatism is assumed and inclination of central line caused by defocussing is measured :and the results are used to calibrate the astigmatism. Anomaly of refractive index is detected by the local change of fringe width. With a large mass of glass, numbers of local defects prevent the detection of normal astigmatism, yet in one instance, glass of almost normal astigmatism was found among the samples for the use of Schmidt plate. Decrease of 4.3•10-8 in astigmatism was observed by careful annealing. A test on a large plate of flint glass manufactured by casting-clearly revealed the traces left by streaming of glass.
A self-recording glossmeter of rotating specimen type is devised. The angle between the illuminator and receptor axes is set at 90° which is adjustable to any given value from 45° to 180° and the specimen is rotated. The aperture angles are about 21'×°330' (adjustable) for the illuminator, 32'×°30' for the receptor and the illuminating field has the section of 1cm×1cm. Photomultiplier is used in the receptor and a recording mV-meter as the recorder, its sensitivity being 1 mV/cm. The spectral sensitivity of the receptor is approximated to that of the normal eye by using a correcting color filter, while the light source is a 40W tungsten lamp. The sensitivity for recording can be varied at six steps by a potential divider in the output circuit of 931A. At present the ratio of the maximum sensitivity to the minimum is 200 : 1 and at the maximum sensitivity the recorder gives the deflection of about S cm for white matt surfaces under 45°-45° condition of illumination and viewing, Curves recorded for various types of specimens are shown.
The dark current in photomultiplier tubes has recently come into question in want of larger electron multiplication, and thus it is necessary to develop a new photoemitter with less dark current. Sb-Cs photoemitter is being used extensively as the photocathode of photomultiplier tubes but the dark current of the order of 10-15A/cm2 therein produced is not to be overlooked. For reducing the dark current, photoelectric and optical characteristics of Sb-Cs photoemitter and Sb (Mg)-Cs photoemitter (reported by N. Schaetti) are studied and the mechanism of dark current reduction may be suggested. The reduction may be considered due to the increase of the acceptor density by the addition of Mg but not due to the lowering of Fermi level by the addition of other elements as W. E. Spicer postulated. Further study is needed for final conclusion.
Observation is made on the time required for pure copper wires to fracture under a given tensile load. In general, the probability of occurrence of fracture increases from zero to a certain value with time. This probability-time curve is assumed to be composed of two lines: the one with the probability being zero up to a critical time and the other a constant thereafter. Then this critical time is interpleted as the mean minimum time for the fracture. The mean fracture time and the mean minimum fracture time are very sensitively affected by surface conditions, but the probability of fracture occurrence remains relatively unaffected. Electrolytical polishing then heating and dipping in 3% HgCl2 solution weaken the specimen extremely, but electroplating and diffusion of the deposited metal over the surface layer strengthen the specimen. Raising the annealing temperature is another cause of weakening. The specimen, annealed in air, is weaker than the one annealed in vacuum. From these experimental results, it is inferred that cracks originating from microcracks on the surface of the specimen grow rapidly with the deformation of the specimen and end in complete fracture.
Gradient of magnetic field (6×105 gauss/cm) is measured on the surface of a ferromagnetic iron catalyst by means of electron diffraction. The value here measured is not relative, but absolute. The Hedvall effect in catalysis is reviewed as the effect of a steep magnetic gradient found on the catalyst surface.