Radio has no future." "X-rays are clearly a hoax". "The aeroplane is scientifically impossible.

Quaternions came from Hamilton after his really good work had been done, and though beautifully ingenious, have been an unmixed evil to those who have touched them in any way.

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

I can never satisfy myself until I can make a mechanical model of a thing. If I can make a mechanical model, I can understand it. As long as I cannot make a mechanical model all the way through I cannot understand.

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

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

Suppose that you could mark the molecules in a glass of water; then pour the contents of the glass into the ocean and stir the latter throughly so as to distribute the marked molecules uniformly throughout the seven seas; if then you took a glass of water anywhere out of the ocean, you would find in it about a hundred of your marked molecules.