In 1907 he wrote a short paper on the origin of spectra which argued against the classical theory and pointed the way towards the theory proposed by Niels Bohr six years later.
In 1907 he wrote isang maikling papel sa pinagmulan ng spectra na argued laban sa klasiko teorya at nakatutok ang mga paraan sa teorya sa pamamagitan ng mga iminungkahing Niels Bohr anim na taon na mamaya.