Quenching of mercury resonance radiation and its relation to reactions sensitized by excited mercury atoms

Abstract

1. 1. The purpose of the present paper is to estimate the extent of bright surroundings necessary to abolish the known, adverse effect of dark surroundings upon vision on a small, bright, working field. 2. 2. The test of vision used was the accuracy with which the subject could keep a manually operated stylus in opposition with another, slowly and irregularly moving, mechanically operated stylus. Both of these were seen in silhouette upon a small, bright field. 3. 3. The results here stated are derived from a total of 390,000 measurements. 4. 4. The precision with which the subjects could follow the moving stylus in general was highest with the largest extent of bright surroundings, lowest with the smallest. Although represented by some 65,000 measurements for each of the six sizes of surrounding field used, the results were still somewhat irregular. 5. 5. The extreme difference in precision was from 4.3 to 7.7 per cent. A large part of this difference, 2.8 to 5.6 per cent., occurred when the border of the bright surroundings was pushed outward from 8° to as far as 16° from the visual line. The plotted results would indicate that there is no advantage to be gained by extending the bright surroundings beyond this.