This apparatus is used to find the thermal conductivity of good conductors. Its importance in the field of thermodynamics cannot be understated, hence is a firm fixture in most laboratories. Consisting of copper bar of 300mm long 25 mm in diameter with its one end of the rod is surrounded by a steam jacket, for heating the rod using a boiler, and the other end is kept cool using a spiral tube through which a constant stream of water is made to flow. The copper pipe has tubes for inserting thermometers. fitted in wooden case lined with felt for thermal insulation. The front portion of the case is hinged which can be opened for demonstration. Supplied without steam boiler and thermometer.