In his optical researches, Optiska Undersökningar, presented to the Royal Swedish Academy of Sciences in 1853, he not only pointed out that the electric spark yields two superposed spectra, one from the metal of the electrode and the other from the gas in which it passes, but deduced from Leonhard Euler's theory of resonance that an incandescent gas emits luminous rays of the same refrangibility as those it can absorb.
No seu traballo sobre óptica Optiska Undersökningar, presentado diante a Real Academia das Ciencias de Suecia en 1853, non só indicou que unha faísca eléctrica produce dous espectros superpostos, un do metal do eléctrodo e outro polo gas no que ocorre, senón que deduciu a partir da teoría da resonancia de Leonhard Euler que un gas incandescente emite raios luminosos coa mesma capacidade refracción que os que pode absorber.