"I have often thought that the greatest obstacle to the progress of knowledge is the obstinacy of men in adhering to their old opinions."

"I have always looked upon the study of nature as a means of glorifying God, and of promoting the welfare of mankind."

"Experiment, without reason, is blind; reason, without experiment, is lame."

"I have seen a piece of glowing wood continue to shine in a vacuum, proving that not all light requires air."

"I am persuaded that the knowledge of natural things is a great help to the knowledge of God."