The removal of an electron from the surface of an atom - that is, the ionization of the atom - means a fundamental structural change in its surface layer.

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

In my view the structure of the whole atom was that of an individual, with all its parts interconnected, and the emission of a spectral line appeared to me to be the result of the coherence and co-operation of several electric quanta.

By allowing the positive ions to pass through an electric field and thus giving them a certain velocity, it is possible to distinguish them from the neutral, stationary atoms.

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

Moreover, the abundance of chemical compounds and their importance in daily life hindered the chemist from investigating the question, in what does the individuality of the atoms of different elements consist.

By recognizing that the chemical atom is composed of single separable electric quanta, humanity has taken a great step forward in the investigation of the natural world.