Joseph John Thomson

“ The spectra produced when the positive rays strike salts of the alkali metals are very interesting. The salts give out the lines of the alkali; for example LiCI give out the red lithium line and sodium salts the D line. It is remarkable the lines due to the metal are more easily excited in the salts the than in the metal themselves. Thus if the liquid alloy of sodium and potassium is bombarded by positive rays the specks of oxide on the surface glow brightly with the sodium light while the clean surface remains quite dark. ”

“ When energy has to be transferred from a charged atom to a corpuscle, the latter only receives a very small fraction of the energy of the atom, thus a very small fraction of the energy of the positive rays may be transformed into a kind available for light production. ”