“On a New Chemistry Theory” of Archibald Couper

by Roberto Poeti
                              Introduction to the Essay “On a New Chemistry Theory” of Archibald Couper

Archibald Scott Couper wrote in 1857 a note about his new chemical theory that was presented by Jean Baptiste Dumas at the French Academy and published in Comptes rendus. His presentation was followed by the publication of an essay entitled “Sur Une Nouvelle Theorie Chimique” in Annales de chimie et de physique. The article appeared soon after in the British magazine Philosophical Magazine entitled “On a New Chemical Theory” which contained some important changes from the version French. Almost simultaneously, Friedrich August Kekulé’s article “The Constitution and Metamorphoses of Chemical Compound and the Chemical Nature of Carbon” appeared in Annalen der Chemie und Pharmacie, in which he came to the same conclusions as Couper.

Couper’s Disappearance

In another article on my blog I described the human and scientific events that made A.S.Couper so extraordinary and interesting.  I reserved the precedence of Couper over Kekulè because he appears in this scientific story the most unlucky character, but also more brilliant. After writing his revolutionary essay Couper will soon disappear from the scientific life overwhelmed by his problems. We will no longer remember him. Only Kekulè, on the other hand, will take credit for the discoveries made, and even then famous, it will later become one of the greatest chemists of the nineteenth century.

The Rediscovery of Couper

Ironically, it will be a pupil and successor to Kekulè at the Bonn Chemistry Chair Richard Anschutz who, preparing a biography of his mentor, will come across Couper. It was 1909 when he published “Life and Chemical Work of Archibald Scott Couper”. He will rediscover the greatness of this chemist and tell of his tragedy. Sixty years had passed since Couper’s discoveries of the properties of the carbon atom.

A new vision

What marvels at Couper’s vision is his great freedom and autonomy of thought. After a little more than two years that he began to take an interest in chemistry, having previously done only philosophical studies, at the age of twenty-seven he lays the foundations for a new vision of organic chemistry and the structure of molecules. Its formulas of structure of organic molecules are so similar to our own and so far from the common representations of its time that they formed a fracture in the dominant paradigm of that time. A new vision that will spark criticism and misunderstanding from the chemists community.

A weak spot

While Couper’s thinking is projected forward, in some respects he remains anchored in conceptions that we might say of rearguard.  I am referring to his conception of acids and bases and the formation of salts. The passage of the essay on this topic is frankly difficult to read, unlike the rest of the content where the exposure is clear and effective.

The material at your disposal in PDF

 Archibald Couper’s essay “On a New Chemistry Theory

The book of Richard Anschutz “Life and Chemical Work of Archibald Scott Couper

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