Cylinderical copper rod about 300 mm length 25 mm diameter, one end containing a steam chamber connected to inlet and outlet tubes, other end of copper rod has cavity connected via thermometer pockets to water inlet and outlet tubes. Through two thermometers supports tubes 75 mm apart are inserted in the rod for finding the temperature at two points. Fitted in teakwood polished case packed with felt with removable front, without thermometers.
