"The physical properties of fluid media, as regards change of state, and as regards capillary phenomena, have been closely illustrated in theory by consideration of a model medium, subject to internal expansive pressure, of kinetic or other origin, which is counteracted by the contractive effect of mutual attraction between its molecules—the latter force extending through much the greater, though for ordinary purposes still insensible, range. For liquids, the difference between these two much larger quantities, of different types, constitutes the transmitted hydrostatic pressure."

“The evidence is closing in more and more rigorously that the medium which transmits electrical and radiant effects must either completely accompany matter in bulk in its movements or else be entirely independent of such movements.”

“A very large number of optical phenomena have been examined by various experimenters with a view to detecting an influence on them of the Earth's velocity of translation. The only such influence that has been announced is that found by Fizeau on the displacement of the plane of polarization of light, produced by transmission through a pile of glass plates: according to Fizeau's own view the experiment was uncertain owing to the numerous disturbing causes that had to be guarded against; and this doubt as to the feasibility of the observations has been fully shared by Maxwell and most authorities who have considered the matter.”

“From remote ages the great question with which, since Newton's time, we have been familiar under the somewhat misleading antithesis of contact versus distance, has engaged speculation,—how is that portions of matter can interact on each other which seem to have no means of connexion between them. Can a body act where it is not?”

“The direct knowledge of matter that mankind can acquire is a knowledge of the average behaviour and relations of the crowd of molecules.”