Abstract
The radiometric observation of infrared atomic spectra during the past half-century may be divided into three periods. During the first, relatively short period of point-by-point observation, associated with Paschen, the thermal detector and astatic galvanometer were brought to a high state of perfection. The infrared spectra of alkalis and alkaline earths were explored in this manner. The following 35 years were unproductive in this field of research. A few excellent investigations took advantage of improved devices such as the thermal relay and automatic recording. During the 10 years of the modern period, photoconductive detectors have been incorporated into scanning spectrometers to permit high-resolution observations in the region beyond the limit of photographic response. This article gives an account of new work since 1956. Details of earlier work are covered in previous reports. The status of infrared observations is summarized and completely referenced. An account of current programs for establishment of standards is included.
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