Large increases in cost with questionable increases in performance can be tolerated only in race horses and women.

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 fact that mathematics does such a good job of describing the Universe is a mystery that we don’t understand. And a debt that we will probably never be able to repay.

The only census of the senses, so far as I am aware, that ever before made them more than five, was the Irishman’s reckoning of seven senses. I presume the Irishman’s seventh sense was common sense; and I believe that the possession of that virtue by my countrymen-I speak as an Irishman.

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.

Fourier’s theorem is not only one of the most beautiful results of modern analysis, but it may be said to furnish an indispensable instrument in the treatment of nearly every recondite question in modern physics.

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

Heavier-than-air flying machines are impossible.

If you can not measure it, you can not improve it.

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.