Letter from Thomas Gold to Dr J T Wasson, Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California Explains their intetrest in problems of the derivation of the lunar soil and in the course of which have been led to the question of composition a s a function of size fraction. It seems especially important to them to disdcover whether the smallest size fraction has in substantial part a different derivation from that of the ret of the material. This is a type of investigation that should be done anyway. Describes the current position of research into this. 29 July 1974