How did the proton get its name?

On the 15th January 1785, William Prout was born in a tiny village in Gloucestershire. He was the son of a farmer and like most of his generation didn’t have any formal education. At 17 years of age he realised his lack of learning and decided to do something about it resulting in him eventually graduating as a Doctor from Edinburgh University in 1811; no mean feat for a farmer’s son!

Although his main career was in medicine his passion was for Chemistry and he spent any spare time he had researching new ideas and finding links between medical and chemical science. He was the first person to isolate Hydrochloric acid from gastric juices and he also started the classification of food types we use today such as sugars, starches and oils.

However, his main contribution to the world of Chemistry was a theory he put forward anonymously, later known as Prout’s hypothesis. He used the atomic weights available at the time for some of the known elements and came up with the idea that all these weights were multiples of the atomic weight of the Hydrogen atom. He called this unit of weight a ‘protyle’ and theorised that the Hydrogen atom was the only fundamental particle. Now, obviously this was later proved to be not quite true due to the binding energy involved between nucleons but at the time this was seen as a plausible idea. So much so that when Ernest Rutherford discovered the existence of the positive particle in the nucleus in 1920 he called it the ‘proton’ in recognition of Prout’s contribution. The proton is considered by Chemists as a fundamental particle and is the main component of the Hydrogen atom. He also had the SI unit of energy involved in nuclear binding, the Prout named after him.