Paschen in 1896 identified an unmistakable oxygen triplet in the infra-red, which is shown terrestrially only in the vacuum tube, where the spectrum is very different from that of atmospheric absorptions.
Paschen in 1896 identified an unmistakable oxygen triplet in the infra-red, which is shown terrestrially only in the vacuum tube, where the spectrum is very different from that of atmospheric absorptions.