A leaf out of Newton’s notebook
Sometime between 1661 and 1665, an undergraduate Isaac Newton took an unlikely academic diversion from his pursuits of mathematics, optics and physics. A neat black-ink notebook jotting, sourced back to his Cambridge University days, reveals that Newton in fact briefly pondered plants too.
Titled quite simply ‘Vegetables’ (and entered between his notes on ‘Philosophy’ and ‘Attraction Electricall & Filtration’) Newton hypothesizes how plants transpire — or how water rises from roots to leaves — against the pull of gravity. Most intriguingly, “His ideas came over 200 years before botanists suggested an extraordinary and now widely accepted theory that explains how plants, from herbs and grasses to the Earth’s tallest trees, transport water from roots to leaves,” says a comment in the latest edition of the journal Nature Plants.
In distinct Early Modern English, Newton describes the process by which fluid matter “continually arise up from the roots of trees upward leaving dreggs in the pores.” This “makes the plant bigger untill the pores are too narow for the juice to arise through the pores & then the plant ceaseth to grow any more.”
What appears to be described here “is the evaporative escape of water from a shoot — transpiration — driven by energy from the Sun,” says the Comment.
It does indeed come as a surprise that Newton dwelt on plant physiology in the middle of his math pursuits at Trinity, author of the Comment David Beerling FRS, Sorby Professor of Natural Sciences, University of Sheffield, told this Correspondent by email.
While there is very little known about the context of his jottings on plant fluids, it could be that he had the note book with him when he retreated from Cambridge to Woolsthorpe Manor (Lincolnshire) in the summer of 1665 to avoid the plague. “Conceivably, it may have been his sojourn in the English countryside that inspired it. But really this is pure speculation.”
The notebook was first judged “not fit to be printed” by Newton’s executor, but later in 1872, it was later presented to Cambridge University Library by the fifth Earl of Portsmouth.
“In the minds of most, Newton’s association with plants begins and ends with the famous apple falling incident and his discovery of gravity. But notes buried within one of Newton’s undergraduate notebooks suggest otherwise,” says the Comment.
