It is more likely that more than a century will pass before we know the structure of the chemical atoms as thoroughly as we do our solar system.

The emitters of the spectral series are without exception single atoms, not compounds of atoms.

We have learnt through experience that when an electrical ray strikes the surface of an atom, an electron, and in some circumstances a second and even a third electron, can be detached.

The movement of the emitters of the spectral lines may be deduced on the basis of the Doppler principle.

A beam of luminous hydrogen canal rays has, owing to its velocity, exactly the same direction as that of the electric field in which it may be made to move.

If the experimental physicist has already done a great deal of work in this field, nevertheless the theoretical physicist has still hardly begun to evaluate the experimental material which may lead him to conclusions about the structure of the atom.

Along a series of lines running from longer to shorter wavelengths the effect of the electric field becomes greater as the serial numbers increase - that is, as the wavelength decreases.