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.
