For demonstration of transpiration rates and rates of water absorption by a cut shoot under various external conditions. A plant shoot is sealed into a stopper which f its the end tube, and the whole apparatus is filled with water, the open end of the capillary tube, which is graduated in mm dipping into beaker of water. The poisition of the air bubble may easily be adjusted byopening the glass stopcock to admit water from the central reservoir. The whole apparatus isVmounted on varnished wooden base by spring clips. Height to top of reservoir 170 mm Diameter of reservoir 20mm, Length overall 320mm.