Absolute intensities in the spectrum of quartz mercury arcs and their variation with temperature-changes of the surrounding air

Variations in intensity of the more important lines in the mercury are spectrum are investigated as the temperature of the air surrounding the burner is increased. The intensity and arc watts reach maxima but not quite together. Empirical relations are found connecting intensity and electrical input. Absolute intensities of some thirty lines between 7000 and 2300 A emitted by commercial quartz mercury-vapour burners are tabulated and some theoretical aspects of the results are discussed.