Filings coherer, glass tube formed into T-shape at one end and bent round into U-shape at other end with bulb, 1899 1899
Engraving: Watt's first experiment. Marcus Stone ARA pinxt; Herbert Bourne sculpt; published by Appleton & Co 1879
Model of Robert Duncan's screw propeller, with stern frame and rudder, as fitted to the Egyptian government yacht 'Sareea 1886-1887