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.

The vortex theory [of the atom] is only a dream. Itself unproven, it can prove nothing, and any speculations founded upon it are mere dreams about dreams.

The more thoroughly I conduct scientific research, the more I believe that science excludes atheism.

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

Do not imagine that mathematics is hard and crabbed, and repulsive to common sense. It is merely the etherealization of common sense.

I have no satisfaction in formulas unless I feel their numerical magnitude.

At what time does the dissipation of energy begin?