. Carnegie Institution of Washington publication. DISTRIBUTION OF ENERGY IN FLUORESCENCE SPECTRA. 181 was placed in front of slit b. In the figure, A is the comparison flame; si and s2 are screens to prevent stray light from entering slit a; f is the cell of fluorescent liquid, and C. II. is the Cooper-Hewitt mercury arc lamp. The procedure was as follows: vSlits a and b were set at equal widths of 50 divisions = cm. The comparison flame was then moved up to a point on the track just in front of the aperture in screen s2- The observing telescope was set for that region of the spectrum corr
. Carnegie Institution of Washington publication. DISTRIBUTION OF ENERGY IN FLUORESCENCE SPECTRA. 181 was placed in front of slit b. In the figure, A is the comparison flame; si and s2 are screens to prevent stray light from entering slit a; f is the cell of fluorescent liquid, and C. II. is the Cooper-Hewitt mercury arc lamp. The procedure was as follows: vSlits a and b were set at equal widths of 50 divisions = cm. The comparison flame was then moved up to a point on the track just in front of the aperture in screen s2- The observing telescope was set for that region of the spectrum corresponding with the maximum of the fluorescence band to be measured. The fluorescent solution in cell / was diluted until its spectrum for that region was slightly stronger than the corresponding region in the spectrum of the comparison flame. By slightly shifting the. 63y& Fig. 176.—Eosin (to left) and resorufin. The observed points are marked by circles. .S4 S6A Fig. 177.—Fluorescein. The observed points are marked by circles. observing telescope in either direction two places could now be found, lying a short distance from the crest of the fluorescence band, at which the two spectra were of equal brightness. The circle readings of these positions were noted, and the position of the comparison flame was read upon the scale of the photometer track. The flame was then moved to a slightly greater distance from slit a, and two new positions were found for the observ- ing telescope, corresponding to points of equal brightness of the band farther from the crest. In this way the entire band was explored several times, and from these sets of readings the intensity of the band at various wave-lengths was computed in terms of the corresponding intensities of the spectrum of the acetylene Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perf
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