GAS CONVECTION APPARATUS (VENTILATION APPARATUS, CONVECTION BOX) For demonstrating the phenomenon of convection in air and the principle of room ventilation. Consists of an enamelled metal box (l x w x h), 20 x 10 x 10cm, having a sliding glass door and two glass chimneys. When a candle in a socket is placed under one chimney and a smouldering tape or touce paper is placed underneath the other chimney, the flow pattern of smoke dramatically illustrates the formation of convection currents. Candle, socket, tape or touce paper are not supplied. Qty :