"It is not often that a man has the opportunity to be useful to his fellow citizens without any personal risk."

"The human mind, like the human body, requires nourishment."

"I have been so lucky in life, that I have had nothing to do but to collect the fruits of the labours of others."

"The more I study, the more I am convinced of the existence of a superior intelligence."

"I shall be happy if my work contributes to the progress of the sciences, and to the well-being of mankind."