hiː pˈʌblɪʃt ɐn ˈætləs ʌvðə spˈɛktɹə fɔːɹ lˈeɪttˈaɪp kˈɑːɹbən stˈɑːɹz, ænd ˈɔːlsoʊ dɪtˈɜːmɪnd ðə spˈɛktɹəl fˈiːtʃɚz ʌvðɪ ˈaɪsətˌoʊp kˈɑːɹbən θˈɜːtiːn.
He published an atlas of the spectra for late-type Carbon stars, and also determined the spectral features of the isotope carbon-13.