Abstract

<h2>Acta Crystallographica Section A</h2><h3>Crystal Physics, Diffraction, Theoretical and General Crystallography</h3><h3>0567-7394</h3> <h2>book reviews</h2> Volume 27 Part 5 Page 508 September 1971 <h2> Crystal geometry. A set of tranparencies for an overhead projector with notes for lecturers </h2> P. Main Crystal geometry. A set of transparencies for an overhead projector with notes for lecturers. Lon- don: ITL. Vufoils Ltd., 1970. Price Unit HI: 5 foils £2.75; Unit CI: 9 foils £3.90; Unit 2:3 foils £1.65; Unit 3:3 foils £1"60; Unit 4:5 foils £2.25; Units 5: 9 foils £3.63. ITL Vufoils are diagrams related to a variety of topics, produced on transparent plastic, which can be used with an overhead projector. Several complete sets are available from the manufacturers or individual frame units may be purchased if so desired. Only the set of diagrams on crystal geometry will be reviewed here. The diagrams are well produced on flexible, transparent plastic sheets, set in a more rigid frame for easy handling. There are several diagrams in each frame, arranged in such a way that only one may be viewed or any combination of them used as overlays and projected simultaneously as a composite diagram. The location of each overlay is quite positive