"The mind of man is like a mirror, which reflects the images of things, but does not always reflect them truly."

"It is an unscientific habit to give names to things before we know what they are."

"I have been battering away at Saturn, returning to the charge every now and then. I have effected several breaches in the solid ring, and now I am splash into the fluid one, amid a clash of symbols tr…"

"The only laws of matter are those which our minds must fabricate, and the only laws of mind are fabricated for it by matter."

"The mathematical difficulties of the subject are so enormous that it is only by great patience and perseverance that we can hope to overcome them."