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.

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.

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.

The discovery of various phenomena has led to a recognition of the fact that the chemical atom is an individual which again is itself made up of several units into a selfcontained whole.

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

The question of the composition of perceptible objects is one which already occupied the mind of the ancient Greeks.

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