“What is not started today is never finished tomorrow.”

“Whether one show one's self a man of genius in science or compose a song, the only point is, whether the thought, the discovery, the deed, is living and can live on.”

“A person hears only what they understand.”

“Duty is the demand of the hour.”

“He who cannot draw on three thousand years is living from hand to mouth.”

“All life is an experiment. The more experiments you make the better.”

“The Good Spirit never cared for the colleges, and though all men and boys were now drilled in Greek, Latin, and Mathematics, it had quite left these shells high on the beach, and was creating and feeding other matters [science] at other ends of the world.”

“Nature is a rag-merchant, who works up every shred and ort and end into new creations; like a good chemist, whom I found, the other day, in his laboratory, converting his old shirts into pure white sugar.”