It will be seen that the correlation is very marked, and that it appears to furnish good evidence that the theory of thermal ionization predicts correctly the relative tendencies of the atoms to absorb the different frequencies. The fractional concentrations are of course not absolute values, as the number of atoms in a state of high excitation is a definite fraction, not of the whole number of atoms, but of the number left over from the lower excitations. Neither are the intensities given by Rowland absolute, and therefore the comparison appears sufficient to show the strong correlation between excitation potential and solar intensity.
FOOTNOTES:
[370] Proc. Roy. Soc., 99A, 136, 1921.
[371] M. N. R. A. S., 83, 403, 1923; ibid., 84, 499, 1924.
[372] M. N. R. A. S., 83, 403, 1923.
[373] M. N. R. A. S., 84, 499, 1924.
[374] R. H. Fowler, Phil. Mag., 45, 1, 1923.
[375] Bohr, Mem. Ac. Roy. Den., 4, 2, 76, 1922.
[376] Ap. J., 59, 1, 1924.