Letter from Thomas Gold to Professor W H McCrea FRS, Astronomy Centre, School of Mathematical and Physical Sciences, University of Sussex, Falmer, Sussex, Brighton, UK Has just sent the enclosed to 'The Observatory'. Discusses some doubts McCrea had at the time it was presented. He expects McCrea has seen some of the backwash form his London lecture on methane from the deep Earth. States that by now there is a large amount of interest and major research programs are under way. 8 August 1978