Letter from Thomas Gold to Dr Joseph W Berg Jr., Division of Earth Sciences, National Research Council, 2101 Constitution Avenue, Washington DC In relatio to the requested advice by ONR on Communication through the Earth's Crust mentions in the Executive Committee Agenda, he is sending a description of a system that he and Donald Menzel worked on some years ago. It seems to have relevance to the problem. Asks for this to be handed over to whoever is now responsible for preparing this advice. 20 February 1971