Ventilation Apparatus (Convection Apparatus)
A rectangular metal box 220 x 75 x 75 mm (L x W x H), with sliding glass front and two openings on top to place glass chimneys. A candle holder fitted to base of box beneath the one chimney. Supplied without candle. Convection may be demonstrated by use of smoke from a string held close to the top of unheated chimney..