The Number of Radiating Atoms in a Hydrogen Discharge Tube

About 90% of the energy radiated from a long hydrogen tube filled with moist hydrogen at a pressure of 0.54 mm of mercury and absorbing 400 watts was found to be carried by the first three lines of the Balmer series. From the measured values of this energy and of the relative intensities of $\mathrm{H}\alpha$, $\mathrm{H}\beta$ and $\mathrm{H}\gamma$, the number of quanta of these lines emitted per atom per second was calculated to be 2.84, 0.43 and 0.10, respectively.