Abstract
A REGISTERING MICROPHOTOMETER.—In 1912 Dr P. Paul Koch described a registering microphotometer designed by himself; the apparatus records photographically the varying intensities of a series of objects such as the lines in a spectrum or a set of interference rings and show their distance apart. The principle-involved is to move the negative to be measured slowly in front of an opening through which a beam of light from a constant source is passed, and the resulting changes in the intensity of this light are recorded on a moving photographic plate. Dr. Koch now describes (Contributions from the Mount Wilson Solar Observatory, No. 77) an application of this instrument to the study of certain types of laboratory spectra, and displays in diagrams the resulting curves obtained. Thus, there are types of curves for furnace lines for different temperatures, for lines displaced by pressure, reversed lines, tube-arc lines, etc. While the observations described are stated to be only preliminary and very limited in scope, they are sufficient to indicate the usefulness of the instrument in those branches of spectroscopy in which it is desired to investigate quantitatively measures of line-intensity and structure.
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Our Astronomical Column . Nature 93, 278 (1914). https://doi.org/10.1038/093278a0
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DOI: https://doi.org/10.1038/093278a0