ELECTRIC BELLS, DEMONSTRATION MODELS : Electric Bells, Telegraph, Telephone, Reflecting Galvanometers and Accessories, Ammeters, Voltmeters, Galvanometers, Wheatstone Bridges, Meter Bridges, Potentiometers, Dial Type Potentiometers, Dial Type (Decade) Resistance Boxes and Capacitance Boxes, Electric Motors and Generator Models, Lamps, Lamp holders, Transformers, Induction Coils Etc VACUUM APPARATUS : Crooke's Tubes, Crooke's Radiometers, Geisseler's Tubes, cathode Ray Tubes for Demonstration of : Heating Effect, Deflection in Magnetic Field, Diffraction, Shadow and Stencil, Phosphorescence, Spectrum Tubes showing Discharge in Argon, Krypton Hydrogen, Cabon Dioxide, Mercury, Neon Etc Boyles law apparatus, barometer, clinostate, fly wheel, Newton colour disc, hooks law, optical bench, resonance apparatus, ripple tank, telescope, ticker tape timer, wave motion, wind vane,