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.

I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind.

[Of the ether] it is no greater mystery at all events than the shoemakers' wax.

Vortices of pure energy can exist and, if my theories are right, can compose the bodily form of an intelligent species.

Overwhelmingly strong proofs of intelligent and benevolent design lie around us... the atheistic idea is so nonsensical that I cannot put it into words.

You know only insofar as you can measure.

Questions of personal priority, however interesting they may be to the persons concerned, sink into insignificance in the prospect of any gain of deeper insight into the secrets of nature.