The collection consists of eight series. The attempt has been made to maintain the original order as much as possible, and particularly in the correspondence and scientific data series. Much of the material, however, was transmitted and accessioned in small portions in the years 1963-1966, and in some cases items were placed on display in the Library before being arranged in series. The microfilming, moreover, was carried out before the final arrangement and analysis of the collection could be made; somewhat premature filming decisions have, therefore, affected the final arrangement that is presented here and some items are missing or poorly described on the film.