Grayson Diffraction Grating

Contained in brown cardboard box: Label on top - "Grayson Diffraction Grating, Quartz wedge, Maltwood Finder. From: The Royal Microscopical Society Tavistock House South, Tavistock Square, London, W.C.1." Envelope (empty) with writing "98.10.19.1 DIFFRACTION PLATE Given by H. J. Grayson made by H. J. Grayson RMS nn, Curner(?) 435". Five glass slides - (1) plain (2) with yellowed glass section added (3) greenish colour with inscription "Sel ... wedge ..." (4) black ceramic(?) slide with glass circle in the centre (5) slide with covered square in centre, stickers "OC 48" "Royal Micro. Society", inscription "Maltwood Finder <--<<< Stop R & J Beck London" Envelope "cat. 435 Grayson containing one glass slide.