Crescograph

A crescograph is a device for measuring growth in plants. It was invented in the early 20th century by Sir Jagadish Chandra Bose, an Indian scientist.

The Bose crescograph uses a series of clockwork gears and a smoked glass plate to record the movement of the tip of a plant (or its roots) at magnifications of up to 10,000.

Marks are made on the plate at intervals of a few seconds, demonstrating how the rate of growth varies under varying stimuli. Bose experimented with temperature, chemicals, gasses and electricity.

A Bose inspired modern electronic Crescograph was designed and built by Randall Fontes to measure plant movement at Stanford Research Institute for which culminated in a report “Organic Biofield Sensor” by H. E. Puthoff and R. Fontes.

The Electronic Crescograph plant movement detector is capable of measurements as small as 1/1,000,000 of an inch. However, its normal operating range is from 1/1000 to 1/10,000 of an inch.

The component which actually measures the movement is a differential transformer. Its movable core is hinged between two points. A micrometer is used to adjust and calibrate the system. It could record plant growth magnifying a small movements such as 10,000,000 times.