Linear Expansion Apparatus, Micrometer Screw Form

A 500 mm long metal rod is supported in a plated brass tube with three tubules for steam inlet, outlet and thermometer. The tube is mounted on a stand with an adjusting screw at one end and a micrometer screw reading to 0.01 mm on the other, with terminals for connecting a bell or galvanometer to indicate contact. With copper, brass and iron test rods but without thermometer.