Letter from Thomas Gold to Dr Michael Duke, Curator, Lunar Samples, Johnson Space Center, Houston, Texas Concerning the particle size separator which they designed there in the course of last year and which is sitting on Gold's shelf in working order. Since the termination of their sample contract they have no funds for using it, and he has had to dismiss the technician who built it. It is a fine instrument, and it would be most important to use it. Duke may know that Mr Maurette has demonstrated that the finest size fraction has in some instances a different composition from the slightly larger fraction. If this is frequently so it totally undermines the whole picture that the soil is largely derived by a local grinding process. Gold finds it hard to understand why this aspect of the investigation does not receive first rate attention. He can do nothing about it in the present circumstances other than to make sure that it is known that a good instrument has been developed for the purpose and is ready to be used. 22 August 1973