A plant may look still, but beneath its leaves and stems, it is constantly changing. Roots are extending through the soil, stems are growing towards light, and cells are responding to changes in their surroundings.

The problem, more than a century ago, was that these movements were simply too slow for the human eye to observe.

That is where Indian scientist Jagadish Chandra Bose stepped in.

In the early 20th century, Bose developed the crescograph, an ingenious instrument that could magnify the growth of a plant thousands of times and record movements that were otherwise almost impossible to see. His work opened up a new way of studying plants, allowing scientists to investigate how they responded to light, temperature, chemicals and other stimuli.

How do you record a movement this tiny? 

Plant growth is deceptively slow. In his later work, Bose noted that the average rate of growth could be as little as about 1/100,000 of an inch per second.

At ordinary magnification, researchers could therefore wait for hours before a measurable change became apparent. But over such long periods, factors such as temperature and light could also change, making experiments harder to control.

Bose wanted a way to shorten this observation period.

His answer was the crescograph, a name derived from crescere, meaning “to grow”. The instrument used delicate mechanical and optical arrangements to amplify tiny movements at the growing tip of a plant.

In his high-magnification version, one lever magnified the movement 100 times, while a second lever........

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