The apparatus consists of a horizontal corning glass tube open at both ends. The heating element is a coil about 40cm long of Ni- chrome wire and is wound spirally inside the axis of the glass tube. The element is easily detachable and is encased in a wooden case lined with felt and provided with a hinged cover. Terminals are brought at each end of the tube for the electrical supply. The horizontal tube is connected either by rubber tube or rubber cork to the inlet and the outlet system, each having a short vertical extension to accommodate a thermometer. The complete apparatus is mounted on a polished wooden base board. Supplied with constant level tank fitted on stand but without thermometer & transformer.