“Is the Airship Possible? That depends, first of all, on whether we are to make the requisite scientific discoveries… the construction of an aerial vehicle … which could carry even a single man from place-to-place at pleasure requires the discovery of some new metal or some new force.”

in his Nobel lecture http://nobelprize.org/nobel_prizes/chemistry/laureates/1987/pedersen-lecture.html, December 8, 1987.

With No Apologies (1979)
Context: My faith in the future rests squarely on the belief that man, if he doesn't first destroy himself, will find new answers in the universe, new technologies, new disciplines, which will contribute to a vastly different and better world in the twenty-first century. Recalling what has happened in my short lifetime in the fields of communication and transportation and the life sciences, I marvel at the pessimists who tell us that we have reached the end of our productive capacity, who project a future of primarily dividing up what we now have and making do with less. To my mind the single essential element on which all discoveries will be dependent is human freedom.

‘Hypothesis and Imagination’ in The Art of the Soluble, 1967.
1960s

I Am A Dancer (1952)

A modern public university, Nature Materials 6, 465 - 467 (01 Jul 2007), doi: 10.1038/nmat1935, Commentary.

Session 82, Page 314
The Early Sessions: Sessions 1-42, 1997, The Early Sessions: Book 2

reported by Lance Dixon http://www.preposterousuniverse.com/blog/2013/10/03/guest-post-lance-dixon-on-calculating-amplitudes/

On the Agriculture of England (1840)