Two files, as follows:
1) Labelled Kasimir, contains correspondence with 'Lew' in Connecticut, 1966; figures, tables and graphs; and correspondence concerning the publication of a paper in Acta Crystallographica; also contains a subfile labelled 'Kasimir's calculations of lattice parameters';
2) Contains bundles of negatives, presumably the photographs referred to in Helen Megaw's file label [1966?].