Written in 1966 and no doubt completely unintelligible to me - if not a few clever clogses here it is now available to download from Cambridge University. The demand was so great this morning that the site crashed. It is all about what happens when the universe expands and you can find it here:
https://www.repository.cam.ac.uk/handle/1810/251038
(just tried and it is 'down for maintenance)