The Four Elements and Properties /(Adapted from: Read, 1995)
Recently, during an interaction with one of my colleague who does not hail from science background at tertiary level but pursued education not related to science stream after schooling. I got to know his knowledge about what human are made of? Same view got echoed from another person, who was even in the past was a registered medical practitioner in my village, which of course linked to practice modern science. Perhaps it does not make any difference most of the time, belief developed as practiced in society for long of period of time. And I believe quite big chunk of population even being literate to date have the same belief: life is made of four basic elements – fire, air, earth, water.
Ancient Greek philosophers believed in the existence of five classical elements – fire, air, earth, water and ether. Ancient Hindu scriptures also refer to panchabhuta or the existence of these five classical elements – kshiti, ap, tej, marut, byom (earth, water, fire, air and ether). Modern day literature of Angels and Demons by Dan Brown, Harry Potter series of J K Rowling etc. also refers to this idea of four elements. Even several artists (Giorgio Vasari, Giuseppe Arcimboldo, Jan Lievens) of all ages explored the existence of these four or five basic elements through their paintings or sculptures (1).
But two of those interactions intrigued me to clear some of the misconceptions on “what are we made of?” as prevailed in our society even today. Let us go back to the history of around 450 BC where actually this belief had prevailed and was called as “Alchemy Period”. Even stalwart philosopher like Aristotle used to subscribe to this notion. Aristotle suggested for an additional special element, ether. This addition of ether as special element was because of the hesitation to accept that how heavenly bodies like stars presumably so hot and to be on fire all the time would be composed of same earthly elements? There has to be something special for heavenly bodies as our common perception. The contribution of these four elements were also linked to human temperament and behavior.
In addition to the belief of these four/five elements, an additional substance named as phlogiston developed by German Alchemist (Johann Joachim Becher) and further nurtured by another Alchemist Georg Ernst Stahl was dominant at that age. Stahl believed that every combustible substance contained a universal component of fire, which he named phlogiston, from the Greek word meaning inflammable. It was reasoned that combustible substance like charcoal lose weight on burning because of the loss of phlogiston component of the air. Apart from Charcoal, metals are also combustible by this theory and when metals are heated (Calcination) in air, the products obtained are termed as Calx.
Metal Heat Metal calx + phlogiston
The calx or ash is ‘lighter’ (less dense) than the metal because it has lost phlogiston. But true science is always measurable and quantitative. And in this case quantitative experiments revealed exception to the phlogiston theory with the fact that some metals gained mass and become heavier when they burned, even though they were supposed to have lost phlogiston and become lighter (2). Becher and Stahl knew that after heating a metal, although a calx may be ‘lighter’ with regards to density, its weight is actually heavier than the original metal. This had been earlier proved by Jean Rey in 1630 and confirmed by Robert Boyle in 1673 (3).
So there was a contradiction between the concept or hypothesis and experimental observation, which is absolutely not acceptable in Science. The concept that these four elements made up all matter was the cornerstone of philosophy, science, and medicine for about two thousand years. It was a deep rooted belief that even Joseph Priestley who discovered oxygen in 1774 called it ‘dephlogisticated air’. He heated mercuric oxide (or calx) with sunlight and the colorless, odorless, and tasteless gas emitted from the lump caused a flame to burn intensely and kept a mouse alive about four times as long as a similar quantity of air. Priestley called the substance "dephlogisticated air" on the theory that it supported combustion so well because it had no phlogiston in it. Hence it could absorb the maximum amount during burning (3).
Then what happens? In the next post.
1. Ipseand ~ Welcome to My Playground! (https://ipseand.wordpress.com/2013/09/21/fire-air-earth-water-and-art/)
3. Education Chemistry (Royal Society of Chemistry), https://edu.rsc.org/feature/the-logic-of- phlogiston/2000126.article
Dr. Susanta Pahari is a Professor of Biochemistry in Skyline University Nigeria. He has a PhD in Biochemistry from University of Calcutta, India.