Records growth of a plant as a series of horizontal traces, the gap between which represents one hour’s growth. The recording lever has 3 notches giving x5, x7 and x10 magnifications and is mounted on an adjustable pillar to adjust its height and pressure on the pencil tip. The recording drum has a pull-through vertical slot which enables the lever to take up the slack in its thread and then draw a new trace at a lower level, on base. Lever is 680 mm and drum is 300 x 150 mm, circumference x-height. With paper strips, pencil, motor for drum, working on 220 / 240 V AC.