The Intensities of the Lines in the Spectrum of Mercury

Number of quanta emitted per atom.---The total radiation, measured with a thermocouple, in the spectral region 6000 to 2300A from a small quartz mercury lamp of known size filled with mercury vapor at a known pressure was 1.85×{}10^-10 ergs per atom per sec. From this and the intensities of the lines it came out that each atom on the average emitted each second 11.4, 8.9, 5.0, 2.3, etc., quanta of yellow, green, blue, violet, etc., light, respectively.The intensities of the lines.---The intensities of twenty-four lines of the spectrum were measured with a quartz spectrograph, a thermocouple and a photoelectric cell, all calibrated, and in some cases with a photographic densitometer. Plotting the logarithm of the intensity against the frequency for the lines of a series gave roughly straight lines of about the same slope for the sharp series (2³Pₙ-m³S₁) and for the diffuse series (2³Pₙ-m³D₁₂₃). The temperatures of the excited atoms derived from the slopes were 3900^∘{} and 2600^∘{} Kelvin for the sharp and diffuse series, respectively.