Although mechanical energy is indestructible, there is a universal tendency to its dissipation, which produces throughout the system a gradual augmentation and diffusion of heat, cessation of motion and exhaustion of the potential energy of the material Universe

I have not had a moment's peace or happiness in respect to electromagnetic theory since November 28, 1846. All this time I have been liable to fits of ether dipsomania, kept away at intervals only by rigorous abstention from thought on the subject.

Science is bound, by the everlasting vow of honour, to face fearlessly every problem which can be fairly presented to it.

We all confidently believe that there are at present, and have been from time immemorial, many worlds of life besides our own. . . . [This] may seem wild, and visionary; all I maintain is that it is not unscientific.

When you are face to face with a difficulty, you are up against a discovery.

If we can't express what we know in the form of numbers, we really don't know much about it.

You know only insofar as you can measure.