A man who is certain he is right is almost sure to be wrong.

Work, finish, publish.

I cannot conceive curved lines of force without the conditions of a physical existence in that intermediate space.

Lectures which really teach will never be popular; lectures which are popular will never really teach.

I will simply express my strong belief, that that point of self-education which consists in teaching the mind to resist its desires and inclinations, until they are proved to be right, is the most important of all, not only in things of natural philosophy, but in every department of dally life.

The world little knows how many of the thoughts and theories which have passed through the mind of a scientific investigator, have been crushed in silence and secrecy by his own severe criticism and adverse examination!

Nothing is ever too good to be true.