With a micrometer screw, the investigation of the rod is measured. The dimension of the brass tube is 50cms x 2.5cm C.P. & it is found with outlet tubes and inlet tubes for steam and open for the reading of the thermometer from 1°C to 110°C. To indicate the exact point of contact of the screw, the binding posts are provided for joining either a buzzer, bell or galvanometer. Three rods of aluminium, brass and iron are also provided without any bell and battery.