and temperature, and that the emanation was produced from 1 gram of radium at the rate of 3 × 10^{-6} c. mm. per second. This amount is in very good agreement with the calculated value, and is a strong indication of the general correctness of the theory on which the calculations are based.
173. Spectrum of the emanation. After the separation
of the emanation and the determination of its volume, Ramsay
and Soddy made numerous attempts to obtain its spectrum. In
some of the earlier experiments several bright lines were seen for a
short time, but these lines were soon masked by the appearance
of the hydrogen lines. In later experiments Ramsay and Collie[1]
succeeded in obtaining a spectrum of the emanation, which persisted
for a short time, during which a rapid determination of the
wave-lengths was made. They state that the spectrum was very
brilliant, consisting of very bright lines, the spaces between being
perfectly dark. The spectrum bore a striking resemblance in
general character to the spectrum of the gases of the argon
family.
The spectrum soon faded, and the spectrum of hydrogen began to appear. The following table shows the wave-length of the lines observed in the spectrum. The degree of coincidence of the lines of known wave-lengths shows that the error is probably less than five Ångström units.
Wave-length Remarks
6567 Hydrogen C; true wave-length, 6563; observed each time.
6307 Observed only at first; evanescent.
5975 " " "
5955 " " "
5805 Observed each time; persistent.
5790 Mercury; true wave-length, 5790.
5768 " " 5769.
5725 Observed only at first; evanescent.
5595 Observed each time; persistent and strong.
5465 Mercury; true wave-length, 5461.
5105 Not observed at first; appeared after some seconds; persisted
and was visible during the second examination.
4985 Observed each time; persistent and strong.
4865 Hydrogen F; true wave-length, 4861.
4690 Observed only at first.
4650 Not observed when the emanation was examined again.
4630 " " "
4360 Mercury: true wave-length, 4359.
- ↑ Proc. Roy. Soc. 73, No. 495, p. 470, 1904.
