Co-operative investigations of quantometric determination of trace impurities and alloying elements in Pb-Sb-Cu alloy have been carried out by Furukawa Electric Co., Yokohama Works and the Kawasaki Branch of Industrial Research Institute of Kanagawa Prefecture, by means of ARL's Industrial Research Quantometer. Point-to-plane methods have been developed for the determination of Ni, As, Sn, Bi, Ag, Cu, and Sb with an accuracy of the order of 3 per cent. High sensitivity and good precision are obtained with overdamped discharge (L 440μH, C 20μF, R 50Ω, V 1, 000V). It is found that briquette samples are very suitable to eliminate possible segregation and make possible to analyse samples of various shapes and sizes.

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Pneumatic cells of Golay type have been constructed to investigate their properties and performances to supplement the data on this infra-red detector.
The construction of the cell is almost the same as that described in Golay's paper in 1949 but with slight modifications.
The heat-absorbing film is made by evaporating antimony on a collodion membrane, because some difficulties were met with in aluminizing it.
The most essential part of the pneumatic cell is the flexible mirror. Unless this mirror is perfectly flat, the image of the line grid becomes indistinct and the amplification of the optical amplifier is considerably reduced. As the collodion membrane of a small area such as used in this cell is very liable to be irregular, some precautions are necessary to prepare the mirror. Namely, the base plate on which the membrane is stuck must be also perfectly flat, the circumference of the cavity must be precisely round, and its edge must be sharply cut.
Another important element of the detector is the line grid. The edge of the grid must be sharp and straight, and the distance between grids must be equal to the width of the grid. As a method to prepare such an ideal line grid could not be found, it was made by the photographic reduction process.Though the grid made in this way gives fairly satisfactory results, the performance would be improved if a better means is available.
To carry out the measurement of frequency characteristics of the cell, the light from the source is chopped by a rotating sector so that the rectangularly modurated beam is generated. The response for the incident light chopped with low frequency decreased with increase of the pneumatic leak, while the high frequency characteristics remained almost unchanged. The leak is made by cutting narrow grooves and the amount of leak was adjusted by the number of grooves .
These cells were used actually as detectors for infra-red spectrometer with LiF prism to test their performance. Fine structures of atmospheric absorption at 2.7μ and absorption of methane at 3.3μ were clearly resolved. Thus it is ascertained that the cell is quite useful for the measurement of weak infra-red radiation.
Ultimate sensitivity of the cell is considered on the basis of the theory due to Golay or Smith and others. The data for various infra-red detectors are compared and it is concluded that this cell will be of great use in the study of far infra-red spectroscopy and in the investigation of fine structure of spectrum for which however large slits and consequently large receiving area are necessary .

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