Letter from Thomas Gold to Donald Friedman, General Motors Corporation, Defense Systems Division, Goleta, California Thinks that Mr Friedman might be interested in the enclosed correspondence [not included with this letter]. Says that 'I think you will find the moon very much in accord with the descriptions I have given you in the past and the best recipe for making a material of similar mechanical properties is still the slightly congealed cement powder. Very few people can now maintain that the surface is composed of congealed lava. A loading that may turn out to be as low as two or three pounds per square inch at impact seems to have pushed down about five inches. It is about the consistency of a medium stiffness of snow and much softer than almost any terrestrial undisturbed deposit. It is not there [sic] dangerously soft, but on the other hand I am not yet persuaded that this makes it completely safe. If I walked around there I would still prefer to be on a line in case I broke in somewhere'. 9 June 1966