Drawing. The Karnak Clepsydra - [Amenophis III : circa 1400 B.C] - Celestial diagram on exterior surface - Small restorations, from tomb of Senmut [1500 BC] & Ramesseum [1300B.C] / Herbert Chatley DSc, MInst CE. - n.d. [original, with Chatley's letterings, 2-12 February 1939, no trace; this is a second one, copy made by Chatley for Science Museum to letter for display, April 1939]. - Black ink, some pencil, with red ink text inscriptions (lettering by Science Museum Drawing Office, April 1939); diagram shaped like layout of truncated cone of vessel, lined off to 43x93cm on sheet 48.5x98cm laid on card 70x106.5cm. - Signed br. - With overlay mount 70x106.5cm; its aperture cut to follow truncated cone shape of image beneath, 39x91.5cm. - No scale marked. - Main diagram shows hieroglyphics on side of clepsydra or early Egyptian water clock from Karnak Temple [taken from photographs of cast in Science Museum, inv.1923-48]. Overlay mount, marked in red ink with dekans and meta dekans, is by Science Museum Drawing Office, April 1939; the whole, as prepared for display in Astronomy Gallery