The distance between the particles of matter is greater in liquids than in solids, and greatest in gases and vapours. It is highly probable that all bodies, even the densest metals, contain more space than matter—in other words, that the atoms are much smaller than the spaces which separate them. Some of our greatest philosophers have held the atoms of matter to be immeasurably small, compared with their surrounding spaces.
Newton thought that the whole material world might be compressed into the space of a single cubic inch, provided that its particles could be brought into actual contact.
Sir John Herschel compares a ray of light penetrating glass, to a bird threading the mazes of a forest; and says that there is no absurdity in imagining the atoms of a solid to be as thinly distributed through the space it occupies as the stars that compose a nebula.
We need scarcely say that these hidden truths do not fall within the sphere of scientific inquiry, but can only be subjects for the exercise of speculation. All our instruments are far too clumsy to help us to a knowledge of atomic magnitudes; the compasses that can measure the interval that separates particle from particle, and the scale that will turn with the weight of an atom, do not belong to man, though the imagination may picture such delicate contrivances in the laboratory of a scientific fairy.
These considerations lead us to a subject about
