Again, the radii of the stable orbits for hydrogen are easily found from Bohr’s assumptions to take the mathematical form ([Appendix G])
In other words, since
is a whole number, the radii of these orbits bear the ratios 1, 4, 9, 16, 25. If normal hydrogen is assumed to be that in which the electron is in the inmost possible orbit, namely, that for which
, the diameter of the normal hydrogen atom, comes out
. The best determination for the diameter of the hydrogen molecule yields
