Letter from Thomas Gold to Sir Bernard Lovell, Jodrell Bank Experimental Station, Lower Withington, Macclesfield, Cheshire, England Says that 'I did not mean to imply that in any joint Arecibo-Jodrell Bank interferometer observation we should tackle the geophysical problems or the problems requiring ultra-precise positional measurements. It is only for those that the superior clocks would be needed'. Goes on to give the reason for this. 13 December 1967