"The greatest discoveries are often made by slight and accidental observations."

"I have always been of the opinion, that the best way to arrive at truth, is to proceed by way of experiment and observation."

"I have always looked upon the study of nature as a kind of religious duty."

"I have often observed, that those who have a great esteem for their own opinions, are very apt to despise those of others."

"The air pump is a philosophical instrument, not a toy."