Atomic theory

First published on FB 09/04/2020

In 1808 John Dalton published ‘A New Theory of Chemical Philosophy’ in which he set out his atomic theory, the foundation stone of our modern understanding of matter. In order to represent the atoms of each element and show how they combine to make molecules and compounds, he devised a set of symbols, each consisting of a circle around a distinct motif or letter.

The drawback of Dalton’s symbols was that many were not easy to remember – why would a triangle represent silicon or a line represent nitrogen? Others were already using symbols based on the first letter of the element within a circle and this idea was developed further by Swedish chemist Jons Jacob Berzelius. He did away with the circles (which caused difficulties for printers) and introduced the letter system that we still use today, based on the Latin names for the elements.

Dalton’s symbols might represent something of a dead end in the development of element symbols, but nevertheless there is something charming about them. These patterns incorporate Dalton’s symbols for oxygen (an empty circle), nitrogen (a vertical line in a circle) and silicon (a small triangle in a circle).

See the originals at https://wellcomecollection.org/works/sx36f5am/items?canvas=1