From the 1968 lecture programme:
In the lectures we have seen how strongly size determines those laws of physics any system will display. The physicist has learned that size is still more fundamental; by working with small objects and with large he has come to realise that the laws of mechanics and electrcitiy are not the only laws of physics. Atoms are in restless motion, which we recognise as temperature; atomic structure itself displays a still more subtle internal motion; and turning to truly giant scale, large enough masses follow the pull of remote bodies in space no matter how we try to hold them still. We enter new physics by treating one single sort of device, a simple vibrator, at every possible scale. Our voyages of scale travel far beyond where Gulliver's ship could sail or modern rockets fly.
Disclaimer: The Ri has replaced the footage of the Tacoma Bridge Collapse with an alternate video of the same event as the original copyright could not be cleared.