Letter from Thomas Gold to Professor G K Wehner, Department of Electrical Engineering, 139 Electrical Engineeering, University of Minnesota, Minneapolis, Minnesota States that his work on lunar sputtering is by no means forgotten, and apologises for failing to reference it in the recent Lunar Science paper, but it was referenced in a fuller paper on the same subject that was submitted to J.G.R. at the same time. Gold supposes they were more aware of the fact that they had also experiments on sputtering and darkening in '63, and their views and his were very similar - and evidently basically correct. 11 May 1976