Giving is the business of the rich.

There is no permanence in doubt; it incites the mind to closer inquiry and experiment, from which, if rightly managed, certainty proceeds, and in this alone can man find thorough satisfaction.

Time does not relinquish its rights, either over human beings or over mountains.

When ideas fail, words come in very handy.

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.

There are but few who have ideas and are, at the same time, capable of action. Ideas enlarge but stymie, action enlivens but confines.

By seeking and blundering we learn.