"My father was a director of the local gymnasium, and my mother was a woman of strong character and great intelligence."

"Why do they [Americans] quarrel, why do they hate Negroes, Indians, even Germans, why do they not have science and poetry commensurate with themselves, why are there so many frauds and so much nonsens…"

"In science we must all submit not to what seems to us attractive from one point of view or another, but to what represents an agreement between theory and experiment."

"The knowledge of the properties of the elements is the foundation of all chemistry."

"Refrain from illusions, insist on work, and not on words, patiently search divine and scientific truth."